Manual

1.        Dirk's Accordion Tuner

This tuner is developed for tuning of accordions and similar `free-reed' instruments such as the diatonic harmonica, the concertina, the bandoneón, the melodica and the reed organ. Dirk's Tuner is developed for professional experienced tuners, but because it gives good insights in the tuning process, it is very suitable for beginning tuners as well.

The unique possibilities of this tuner simplify and accelerate the tuning process considerably. The tuner has a large range from E0 up to C9, a very high accuracy of less than 0.05 Hz (waves of longer than 20 seconds) and can measure to three reeds at the same time. Because of this the tuning of the accordion can be measured without disabling reeds before opening the case. The real frequencies of the reeds which are influenced by each other and by the case can be measured now. This way it is considerably simpler and quicker to select the reed that deviates and needs attention. The tuner measures beatings that arise because the reeds sound together and shows these in Cent or Hertz. Beatings cannot be measured accurately enough by measuring the reeds separately, but by measuring them at the same time it is accurate enough. See chapter 27 for an explanation concerning the accuracy of the tuner. The measured beatings are compared to the beating list of the accordion concerned which indicates the desired beating for each note. This beating list can be produced rapidly and simply using a graph in the tuner.

The tuner can be extended with a module that can record and save all notes of the accordion quickly and create a report afterwards. This report gives the error of each reed in an easy to read table. After opening the accordion, the reeds which deviate too much can be corrected on the tuning table using the values from the report. The reeds (that have a deviated frequency outside the case) will get the correct frequency after being put back in the accordion. The report can be printed again afterwards and join the accordion as a tuning report.

Also chords (three reeds) and octaves (two or three reeds in several octaves) can be measured by the tuner, so the case does not need to be opened for these as well.

Beside the mentioned basic functions, the tuner has a lot of additional functions such as:

-          increase the tuner to a full screen for a clear overview.

-          freeze the screen to be able to examine the numbers and graphs well.

-          play notes using the sound card.

-          automatically or manually select the notes to measure.

-          automatic correction of possible errors in the accuracy of the sound card.

-          automatic reduction of undesirable context sounds and disturbances.

The tuner runs on a pc or laptop with a Windows operating system and works with both built in and externally connected microphones.

Table of contents

1.         Dirk's Accordion Tuner 2

2.         The trial version. 4

3.         Extension modules. 4

4.         A number of important terms. 5

5.         Installation. 7

6.         De-installation. 11

7.         Choice and placement of the microphone. 13

8.         The first use. 15

9.         Tuning. 17

10.        The input signal 22

11.        The equalizer 22

12.        The detected note. 22

13.        The frequency spectrum of the detected note. 23

14.        The errors of the reeds. 23

15.        Manual selection of the note to tune. 24

16.        Measuring long lasting notes. 24

17.        Playing notes. 25

18.        Transpose. 25

19.        Configure the frequency of the A₄ 25

20.        Measuring chords. 26

21.        Measuring octaves. 27

22.        Settings. 29

23.        Beating lists. 32

24.        Tuning accordions. 39

25.        Tuning accordions with the module 'record and report' 40

26.        Noise reduction and accuracy. 47

27.        The accuracy of the tuner 48

28.        Hertz and Cent 49

29.        Beating. 50

30.        The equal temperament 51

31.        An overview of the screens. 52

32.        An overview of the buttons. 53

33.        Shortcut keys and clicks. 54

34.        Frequency table of the notes. 55

35.        System requirements. 58

2.        The trial version

The trial version is meant for getting a good idea of the possibilities of the tuner. Only part of the notes from the scale can be measured with this version. The following notes are supported: E0 F0 G#0 A0 C1 C#1 E1 F1 G#1 A1 C2 C#2 E2 F2 G#2 A2 C3 C#3 E3 F3 G#3 A3 C4 C#4 E4 F4 G#4 A4 C5 C#5 E5 F5 G#5 A5 C6 C#6 E6 F6 G#6 A6 C7 C#7 E7 F7 G#7 A7 C8 C#8 E8 F8 G#8 A8 C9

3.        Extension modules

The tuner can be extended with modules. These extension modules add extra functionality. At this moment there is one extension module available. This module adds the possibility to record and save all tones of the accordion quickly and generate a report. Check the Internet site for new extension modules: http://www.dirksprojects.nl

4.        A number of important terms

•  Frequency
the number of waves per second of a tone (pitch).

•  Sound
the range of waves that can be observed by the human ear.

•  Tone
sound with a fixed pitch.

•  Note
notation for a tone with a specific pitch and length.

•  Scale
increasing or decreasing sequence of tones in a fixed order.

•  Pitch
the perceived frequency of a tone. This is the fundamental frequency.

•  Fundamental tone
the perceived pitch of a sound is that of the fundamental. The fundamental is the lowest tone of the tones from which the sound has been built.

•  Overtone
a tone in a sound with a higher frequency then the fundamental. The overtones of a sound are multiples of the fundamental.

•  Beating
the beating in sound which occurs when two tones with a small difference in pitch sound at the same time.

•  Interval
The difference in pitch between two notes.

•  Semitone
the smallest musical interval that is used in western music. An octave exists out of twelve semitones. In an equal temperament all semitones are equally large.  a piano the interval between two successive white keys is one semitone if there is no black key in between. If there is a black key in between the white keys, then the interval between the two white keys is two semitones. The interval between the white keys and the black one is then one semitone. The interval between a note and the same sharp note (for example C and C^#) is always one semitone.

•  Octave
the difference between two tones of which the frequency of the second tone is twice as high as that of the first.
1 Octave = 12 Semitones.

•  Tuning or temperament
the way the frequencies of the notes are chosen. In Western music the equal temperament is most popular. Other temperaments are for example: the just intonation, the Pythagorean tuning, the mean tone temperament, the well temperament and the 31 equal temperament.

•  Chromatic scale
a chromatic scale is a scale that contains all twelve semitones of the octave:
c – c^# – d – d^# – e – f – f^# – g – g^# – a – a^# – b (the white and black keys of a piano)

•  Half-tone and whole-tone steps
a half tone step is equal to an interval of one semitone such as the interval between two successive white keys on a piano without a black key in between. A complete tone step is equal to an interval of two semitones such as the interval between two successive white keys on a piano that do have a black key in between.

•  Diatonic scale
a diatonic scale is a scale with half and whole-tone steps:
C major: c – d – e – f – g – a – b (the white keys on a piano or the buttons on a diatonic harmonica)
C minor: c – d – e^b – f – g – a^b – b^b

•  Bisonoric
the term 'bisonoric' is used to indicate to that a key of an accordion-like instrument generates a different tone when closing or opening the bellows. Examples: bandoneón, squeeze box, harmonica.

•  Hertz
unit for frequency.
1 Hz = 1 wave per second.

•  Cent
logarithmic unit for the difference in pitch with respect to a tone in the scale.
1200 Cent = 1 Octave.
100 Cent = the distance between 2 successive semitones in an equal temperament.

•  Frequency spectrum
all frequencies that occur in a sound. The frequency spectrum can be presented in the form of a graph.

•  Tuning table
a work table with all kinds of supplies for tuning the reeds of an accordion.

5.        Installation

The tuner exists out of one installation file: an .exe file. During downloading of this file you get the following questions:

In the screen above you can choose 'Run' or 'Save'. By choosing 'Run' the installation file is downloaded and started directly. By choosing 'Save' the installation file is stored on your computer before it is started. By choosing this option you can write the tuner (for example) on a CD afterwards so that you can install it again later.

The screen above is shown after downloading. By choosing 'Run' on this screen the installation file is started. You can always start the stored installation file again later to install the tuner.

Because the Internet Browser does not recognize the tuner, the screen above warns for starting an unknown file. By choosing 'Run', the installation file is actually started.

With the installation program above, the tuner can be installed and possibly de-installed later. By choosing 'Install' the tuner is installed. The files of the tuner are installed in the folder where Windows installs new programs by default. The selected installation folder is shown at the bottom of the screen after 'Program files'. By removing the check mark 'Place icons on your computer's desktop', no icons will be placed on your desktop. By removing the check mark 'Start the application after installation', the tuner will not be started after installation. Generally both check marks should be set.

The screen above shows that the tuner is installed successfully and that it will be started. To be able to start the tuner later on, an icon is placed on the desktop of your computer. This same icon is also placed in the start menu of Windows under 'Dirk's Accordion Tuner Pro V2.2.

The disclaimer

At the first tuner start the so-called 'disclaimer' is shown. This screen states that the author is in absolutely no way responsible for possible direct or indirect damage as a result of the use or inability to use this software. To start the Tuner you must accept this disclaimer by choosing 'Accept'. You can not-accept the disclaimer by clicking on the red cross. The tuner will be closed then.

Activation.

In the activation screen above you can pass on your name, address and e-mail. This data is used to inform you concerning modifications, updates etc. This data is not passed on to third parties. It is not mandatory to fill in this data. You can set the check mark to indicate that you wish not to pass on your name and e-mail address. To continue, choose 'Activate'.

6.        De-installation

With the installation program above, the tuner can be installed and possibly de-installed later. By choosing 'Uninstall', the tuner is de-installed. All files, installed during installation, are removed from your computer. The installation program can be started from the start menu of Windows under 'Dirk's Accordion Tuner Pro V2.2'.

The tuner can also be de-installed by means of the icon 'Software' in the configuration screen of Windows.

7.        Choice and placement of the microphone

The accuracy of the microphone

For the tuner only the frequency of the measured sound is important. The sound volume does not matter. The frequency range of the microphone must run from 20 Hz to 10 kHz at least. The accuracy of the sensitivity of the microphone is not important. The accuracy of the measured frequency is important. This is however easily sufficient in any microphone.

Externally connected or built in

A built in microphone such as those present in the most laptops, is well usable, but catches more surrounding noise than an externally to the sound card connected microphone. The case of the laptop catches up sounds and vibrations and passes them on to the microphone. The cooling fan of the laptop is an important source of surrounding noise. The majority of this noise is suppressed by the tuner as a result of which the built in microphone works nevertheless well. Another, much larger, disadvantage of the built in microphone is that it is impossible (or difficult) to position it right with respect to the accordion. An external microphone, which is connected with a wire to the sound card, can simply be placed on the desired location.

Dynamic or condenser

Microphones can roughly be divided in two groups: dynamic microphones and condenser microphones. More types exist (electret, c-ducer, pzm, crystal, piëzo), but they are a little used.

Dynamic microphones and Jack plug

Condenser microphones, preamplifier and XLR plug

A dynamic microphone exists of a membrane which is placed in a magnetic field. Sound lets the membrane vibrate in the magnetic field as a result of which an electric voltage is generated. This type of microphone can be connected without a preamplifier (and therefore also without a power supply) directly to a sound card and is generally equipped with a so-called Jack plug.

A condenser microphone exists of a conductive membrane which is placed near a fixed, also conductive, plate. Because of this a condenser is created of which the capacity is dependant of the position of the membrane. Sound lets the membrane vibrate as a result of which the capacity of the condenser vibrates as well. By introducing an electric voltage to the condenser, its capacity, and therefore the sound signal, can be measured. This voltage is called the phantom voltage for which a special preamplifier is necessary. This type of microphone cannot be connected direct to the sound card and is generally equipped with a so-called XLR plug.

The dynamic microphone is cheap and can be connected to the sound card directly. The condenser microphone is expensive and needs an expensive preamplifier with phantom power. The better quality of the condenser microphone does not improve the accuracy of the tuner. The tuner works very well with both types but for aforesaid reasons the dynamic microphone is preferred.

Placement of the microphone

The placement of the microphone with respect to the accordion largely determines the sensitivity of the microphone for the accordion reeds that need to be measured. Always place the microphone on the same side of the accordion as the reeds that need to be measured. If the reeds on the keyboard-side are measured then the microphone must be placed on the side of the keyboard. If the reeds on the bass-side are measured then the microphone must be placed on the bass side of the accordion. If the reeds block is taken out of the accordion and it is being tuned on the tuning table, then the microphone must be placed above the reed block so that all reeds can be measured evenly strong. If two reeds sound at the same time (evenly loud) and the microphone is placed at the wrong position, then it is well possible that one of the two reeds is measured much weaker. This will influence the accuracy of the measurement negatively.

The distance from the microphone to the accordion

If the microphone is placed closer to the accordion, the background sounds become weaker, with respect to the sound to measure. This improves the measurement. A distance of less than half a meter gives the best result.

Digital effects

Some microphones come with software (so-called drivers) that can modify the sound signal by means of digital effects. These are effects such as echoes, hum filters, stereo enhancement, direction sensitivity and noise suppression. These effects deform the measured sound signal as a result of which the tuner can not function well. These effects must be disabled in the software of the microphone. The microphone settings 'boost', 'sensitivity', 'volume', 'gain' and 'balance' are no problem.

Conclusion

In practice a simple dynamic microphone that is often provided with the sound card proves to work well. The frequency range of such a cheap microphone is in most cases not known. Especially for the lower tones, a qualitative better dynamic microphone can give better results. The frequency range of this microphone must then run from 20 Hz to 10 kHz at least. The much more expensive condenser microphones are usable, but don't give a better result. Digital effects in the microphone software must be disabled.

8.        The first use

Tool tips

By hovering above a button or a window of the tuner with the mouse pointer for a short time, a so-called tool tip is shown. A tool tip is a small text box with explanation about the button or the window.

Select the sound input

To be able to use the tuner it is necessary to select and configure the desired sound input. Generally this will be a microphone. For this reason the configuration screen is shown at the first start of the tuner.

The left part of the configuration screen above is important for selecting and configuring the sound input. At 'select the recording device' you select the sound card. The different sound inputs of the selected sound card are enumerated at 'select the sound input in the recording device'. Here you select the sound input to use.

The sensitivity of the sound input is configured with the slider 'Sensitivity'. The current signal of the selected sound input is shown in the graph at the bottom. The tuner works best when the input signal is as strong as possible, but to prevent distortion of the signal it should not reach the top or the bottom of the graph. The signal is too strong then and the functioning of the tuner will be influenced negatively. The strength of the signal can be reduced by moving the 'Sensitivity' slider to the left. If a microphone is selected and the signal is too weak, the check mark 'Microphone boost' can be set to amplify the signal more.

The balance of a stereo sound input is configured with the 'Balance' slider. In most cases the balance will have will be set to the middle position.

The button 'Windows Recording Control for the selected device' opens the sound input configuration screen of Windows. This screen is normally not necessary.

A 50 or 60Hz hum in the sound signal can be filtered out by setting the check mark in front of the 'hum filters'. Such a hum is generally caused by the power supply of the computer that is picked up by the microphone. The tuner can detect the hum (when the hum filters are disabled) as a G1 (49Hz), a A#1 (58,27Hz) or a B1 (61,74Hz).

9.        Tuning

See to quiet surroundings

The tuner removes undesirable monotonous background sounds. It is however virtually impossible to distinguish a playing accordion in the background from the desired foreground sounds. The sounds to tune must be louder than the background sounds and the background sounds influence the speed of the tuner negatively. The best result is reached in quiet surroundings with few background sounds.

Wait for the initialization

Start the tuner and wait until the text 'Initializing…' disappears. Shortly after start up the tuner measures the background sounds for approximately five seconds. If a note is played during this period, it will be considered as a background sound. This note will then not be recognized shortly after the initialization. If this happens, then stop playing the note and waits approximately ten seconds before playing the note again.

Notes, octaves or chords

Choose what you want to tune using the buttons 'Octaves' and 'Chords': single notes (none of both buttons pressed), octaves ('Octaves' button pressed) or chords ('Chords' button pressed).

Select the number of reeds

Select the correct number of reeds with the 'Reeds' button. This number must equal the number of reeds that sound at the same time. If more reeds sound than are selected, then the tuner will recognize the loudest reeds, but never more than selected. If the sound volumes of the reeds lie closely to each other and varies a bit then the reeds recognized by the tuner can jump from one to the other and the reading will be difficult. If less reeds sound than are selected, then there is a chance that the tuner recognizes a tone from the background sounds. This chance however is small and if it happens, it is not really a problem, but it makes the reading less clear.

Play the note to tune

Play the note to tune with constant bellow pressure until the red text 'Lock' appears. The pitch of the reed varies a bit with the bellow pressure. If the bellow pressure gets higher the top of the reed will swing back and forth further as a result of which the pitch decreases. For this reason it is important to tune with approximately the same bellow pressure as with which the accordion is played. As soon as the measured note is stable and accurate the red text 'Lock' appears. The tuner will now no longer jump to another note as long as the current note plays.

Do not play the note for too long

The tuner removes long lasting monotonous background sounds such as the sound of a cooling fan. If the note to measure lasts for too long (approximately 30 seconds), then it will be recognized as a background sound and will be removed. If this happens, stop playing the note for approximately five seconds before continuing tuning.

Watch the sound volume

If the sound volume is too high the input signal will deform, which influences the functioning of the tuner negatively. If this occurs regularly, then go to the configuration screen (Menu - Settings) and reduce the sensitivity of the input signal ('Sensitivity' slider). The tuner watches the sound volume and shows to the red blinking text 'input signal too strong!' as soon as the volume become too high.

Check the detected note

The tuner shows the value of the detected note. The octave of the note is shown at the bottom right of the note character. The A of 440 Hz is in octave 4 and is shown as A₄.

Read the errors numerically

The errors of the measured reeds are shown by the tuner numerically. These errors can be calculated with respect to the exact frequency from the scale. This way the reeds must be tuned so that the measured errors are equal to the desired beatings. The moving red needles show the same errors. The errors can also be calculated with respect to the desired beatings from the beating list. This way the reeds must be tuned so that the measured errors are all zero. In chapter 23 it is explained how beating lists can be used. The method that is used to calculate the errors can be configured in the configuration screen (Menu - Settings).

Read the errors with the moving needles

The errors of the measured reeds are also shown by the tuner by means of moving red needles. These errors are calculated with respect to the exact frequency from the scale. The scale of the gauge runs from 50 Cent too low to 50 Cent too high. This is the range of one semitone. This way the reeds must be tuned so that the measured errors are equal to the desired beatings. The errors cannot be calculated here with respect to the desired beatings from the beating list. The absolute frequencies of the measured reeds can be shown in text boxes (in Hertz). With the 'Freq' button at the bottom of the tuner these boxes can be turned on and off.

Read the beatings

The beatings of the measured reeds are shown by the tuner numerically. The 'Hz/Cent' button changes between presentation in Hertz or in Cent.

Freeze the tuner

The tuner can be frozen so that the shown values and graphs remain unchanged and can be read quietly. The tuner is also frozen by pressing the spacebar on the keyboard.

Enlarge the tuner to a full screen

The tuner can be enlarged to a full screen so that the shown values and graphs can be read well, also on a larger distance.

10.    The input signal

The sound signal that the tuner uses for its measurements is graphically shown in the top left corner of the tuner. The degree in which the signal goes up and down indicates the strength of the input sound. If the sound becomes too strong to fit in its window, then the signal is not shown any stronger so that it will always fit in its window. The name of the sound input that is chosen in the settings screen (Menu - Settings) is also shown in this window. You can use this window to check if the input signal is present.

11.    The equalizer

The tuner converts the input signal from a time signal to a frequency signal. The equalizer shows the strength of the measured notes (from E0 up to C9) graphically. Each vertical blue bar reflects the strength of the note concerned. How stronger the note in the measured signal how higher the bar. If one of the bars becomes too strong to fit in its window, then the bars is not shown any stronger so that it will always fit in its window. In this case all notes are shown less strongly so that the note strengths with respect to each other are still correct. In this window also the overtones present in the input sound are visible. The tuner does use these. The strengths of the background sounds are represented by a small horizontal green line. If the blue bar reaches the green line then the tuner recognizes that note as a foreground sound. The tuner selects the note to tune from the foreground sound. The selected note is marked by a dark green background. When tuning chords or octaves several notes are selected.

12.    The detected note

The detected note is shown as a character, an octave number and possibly a sharp sign in the note window of the tuner. The frequency of the tone in the scale is shown in the top left corner of this window. This is not the measured frequency. Below this frequency it is indicated if the note is selected automatically or manually. The configured frequency for the A4 is shown in the top right corner of this window. This is 440.0 Hz by default. If the notes are transposed then this is indicated at the bottom of this window.

13.    The frequency spectrum of the detected note

The vertical blue bar in the equalizer of the detected note covers a small part of the total frequency spectrum (all blue bars) of the input sound. The tuner enlarges the frequency spectrum of this one detected blue bar and shows it graphically in the frequency spectrum window. The horizontal axis represents the frequency and vertical axis represents the strength of the frequencies. The red line shows the frequency spectrum of the detected note. The ends of the red line proceed in white lines. These white lines show a small part of the adjacent notes. The high peaks in the red line indicate the measured frequencies of the input sound. Each sounding reed of the accordion causes a peak in the frequency spectrum. The distance between two peaks determines the frequency of the observed beating. The tuner detects the peaks in the red line and marks these with blue vertical lines. There are no more peaks detected than the number of reeds configured. The configured number of reeds is shown in the bottom right corner of this window. The vertical dark green line indicates the frequency from the scale of the detected note. The vertical light green lines indicate the desired deviations for the reeds from the beating list. The distances between the blue and the green lines indicate the errors of the reeds. If single tones, chords or octaves are measured is shown in the bottom left corner of this window. The calibrated correction factor for the frequencies is shown in the top right corner of this window.

14.    The errors of the reeds

The errors of the reeds are shown numerically and with moving red needles. The beatings are calculated and shown numerically. The absolute frequencies of the reeds can be shown numerically as well. See chapter 9 for an explanation concerning reading the errors and beatings.

15.    Manual selection of the note to tune

If the 'Auto' button is pressed then the tuner selects the note to tune automatically. If this button is not pressed then the note to tune can be selected manually. The note to tune can be selected with the four buttons '- Note +' and '- Octave +'. The left and right arrows on the keyboard can also be used for this. The selected note is marked in the equalizer window with a green background.

Manual selection of the note to tune can be used (among other things) in the following situations:

-          In the automatic selection mode the tuner selects the fundamental of the input sound. In manual selection mode it is possible to measure one of the other tones (for example an overtone).

-          In manual selection mode the tuner reacts more sensitively as a result of which it becomes possible to measure weaker tones.

-          In the settings screen (Menu - Settings) it can be configured that the tuner must measure continuously, in the manual selection mode, also if there is no foreground sound present. This way long lasting sounds can be measured.

-          If many disturbing background sounds are present in the automatic selection mode, it can occur that the tuner selects the wrong note now and then.

16.    Measuring long lasting notes

Long lasting notes will be recognized by the tuner as background sound after approximately 30 seconds. These sounds will then no longer be selected automatically. In the settings screen (Menu - Settings) it can be configured that the tuner must measure continuously, in the manual selection mode, also if there is no foreground sound present. This way long lasting notes and other background sounds can nevertheless be measured.

17.    Playing notes

In manual selection mode the tuner can play notes using the sound card. By clicking on the 'Sound' button the selected note is played for ten seconds. The tuner corrects the frequency of the playing note by means of the calibration which is carried out at start up. Because of this the playing note is not dependent on the accuracy of the sound card. The generated sound wave is sine shaped. Sound volume is strongly dependant on the pitch and the frequency characterization of the used speakers. Without a bass speaker the lower tones (below the C3) can generally not be heard at all.

The playing note can be used to check the tuning 'by ear' or to find the selected note on the accordion quickly. It is also a quick test to check if the tuner is functioning.

18.    Transpose

To tune your instrument in another tone then the standard C, you can use the buttons '- Trans +' in the bottom of the tuner. With these buttons the tuning can be transposed to another tone. In the bottom of the note screen it is indicated where the C of the instrument is transposed to. 'C => C^#' means that when a C^# is measured this is shown in the tuner as a C. All other tones are transposed proportionally. The transpose function only works when measuring single notes and not when measuring chords or octaves.

19.    Configure the frequency of the A₄

To tune an instrument in another pitch then the standard A=440Hz you can use the slider on the right side of the tuner. With this slider the frequency of the A4 can be adjusted between 430Hz and 450Hz in steps of 1Hz. All other tones will change proportionally. If the frequency must be adjusted even further, it is possible to combine the A4 frequency with transposing one or more semitones. See chapter 18. By double clicking on the slider the default frequency of 440Hz is set again. The current pitch (frequency) of the A4 is shown in the top of the note window.

If notes are recorded with the 'Record' button then it is not possible to modify the frequency of the A4. In order to be able to compare the recorded notes it is necessary that the A4 frequency stays the same.

20.    Measuring chords

The tuner can measure chords which exist of three notes. The three notes are measured at the same time as a result of which the tuner is able to show the name of the chord such as: D_m, A, F_sus2 or E_dim. The tuner measures chords if the 'Chord' button at the bottom of the tuner is pressed.

The tuner selects the three notes of the chord from the input sound and marks these in the equalizer window with a dark green background. The name of the chord is shown in the note window. The frequency spectrum window is subdivided into three parts so that the frequency spectra of all three notes can be shown. See chapter 11 for an explanation about the equalizer window. See chapter 13 for an explanation about the frequency spectrum window.

The measured errors of the three reeds are shown numerically and with three red needles. The name of the note from the chord is shown in dark green together with the concerning numerical errors. The errors are calculated with respect to the exact frequency from the scale. The scale of the windows with the red needles runs from 30 Cent too low to 30 Cent too high. The absolute frequencies of the measured reeds can be shown in text boxes (in hertz). The 'Freq' button at the bottom of the tuner turns these boxes on and off.

21.    Measuring octaves

The tuner can measure two or three notes which are an octave apart at the same time. The octaves must be succeeding. It is not possible to skip octaves. If the octaves are not succeeding then these notes can be measured using the manual selection mode. See chapter 15 for an explanation about this. The tuner measures octaves if the 'Octaves' button in the bottom of the tuner is pressed.

With the 'Reeds' button in the bottom of the tuner it is configured if 2 or 3 notes are measured. The configured number of notes is shown in the bottom right corner of the frequency spectrum window. The tuner selects the notes in the successive octaves from the input sound and marks these in the equalizer window with a dark green background. The name of the note and the octave number of the lowest note is shown in the note window. The frequency spectrum window is subdivided into three parts so that the frequency spectra of three notes can be shown. See chapter 11 for an explanation about the equalizer window. See chapter 13 for an explanation about the frequency spectrum window.

The measured errors of the reeds are shown numerically and with the red needles. The name of the note and its octave number is shown in dark green together with the concerning numerical errors. The errors are calculated with respect to the exact frequency from the scale. The scale of the windows with the red needles runs from 30 Cent too low to 30 Cent too high. The absolute frequencies of the measured reeds can be shown in text boxes (in Hertz). The 'Freq' button at the bottom of the tuner turns these boxes on and off.

With notes in several octaves, the beating that occurs between the overtones of the lower octaves and the higher octaves can be heard. This beating is measured by the tuner and is shown in hertz or in Cent. The 'Hz/Cent' button in the top of the tuner changes between Hertz and Cent. In the case of Cent, the beating is calculated with respect to the higher octave.

22.    Settings

The settings screen can be opened by clicking on the 'Menu' button at the bottom of the tuner. A menu will appear in the top left corner of the tuner in which the option 'Settings…' must be chosen. The settings screen can also be opened by clicking on the window with the input signal in the top left of the tuner.

Choosing the sound input

The left part of the settings screen shown below is important for selecting and configuring the sound input. See chapter 8 for an explanation about how to select and configure the desired sound input.

A component of Windows Mixers is 'Windows Recording Control'. This is the place in Windows where the sound input is selected and configured. The settings screen of the tuner does the same as a result of which the Windows settings are not necessary. By clicking on the 'Windows Recording Control for the selected device' button, the Windows settings screen for the selected sound card is opened.

Choosing the image on the main screen

In the top right corner at 'select the main screen image' the instrument that it is displayed in the middle of the tuner is chosen.

How the errors are calculated

In the middle of the right side at 'select how to display the error values' you can choose how the measured reed errors are shown. There are two options:

1.       'Display error values with respect to the straight pitch from the scale'.
With this option the deviation of the reed is calculated with respect to the exact frequency of the note in the scale. This means that, during tuning, the errors shown by the tuner must become equal to the desired beatings.

2.       'Display error values with respect to the desired pitch from the beating list'.
With this option the deviation of the reed is calculated with respect to the desired value from the beating list. This means that, during tuning, the errors shown by the tuner must become zero.

Disable the large tool tips

By hovering above a tool of the tuner (button, window, slider, check mark, text, etc.) with the mouse pointer for a short time, a so-called tool tip is shown. A tool tip is a small text box with explanation about the tool that appears on top of the tuner. These help texts give important information on the functioning of the tuner and are therefore very useful. For the experienced user, that does not need this information any longer, the tool tips are however annoying because they cover a part of the tuner. By enabling the setting 'Disable large tool tips' in the middle of the right side of the tuner, most of tool tips are disabled.

Constantly keep on updating (measuring) in manual selection mode

The measured values and graphs are updated if the tuner recognizes foreground sound. Background sounds are not measured. Foreground sounds which last for a long time (approximately 30 seconds) are also considered background sound. Because of this it is not possible to continue measuring sounds over a long period. By enabling the setting 'Update continuously in manual note detection mode' in the middle of the right side of the tuner, the tuner updates the measured values and graphs ongoing in manual selection mode. This does not work when the tuner is in recording mode. See chapter 16 for an explanation about measuring long lasting notes.

Stop updating (measuring) after the note is locked.

If a detected note is locked, the tuner continues updating the measured values and graphs. By enabling the setting 'Stop updating after lock' in the middle of the right side, the tuner stops updating after the note is locked.

Lists with desired beatings

The tuner can use beating lists. These are lists with the desired beating per note. By clicking on the button 'Edit desired beating values…' in the bottom right corner, the screen with which the beating lists can be created, examined, loaded and saved will be opened. The text above this button shows the currently selected beating list. In chapter 23 the functioning of the beating lists is explained.

23.    Beating lists

Accordions generally have several reeds per note. The different reeds are slightly differently tuned as a result of which a characteristic beating is achieved. The further the pitches of simultaneously sounding reeds lay from each other, the faster the beating. The amount of beating is different for every note. The beating generally gets larger (in hertz) as the notes get higher. The distribution of the amount of beating over the notes of the accordion is different per type of accordion and is stored in so-called beating lists. Each type of accordion has its own characteristic beating list. These beating lists can be created with the tuner. During tuning the tuner shows the desired beatings for the reeds of the note to tune. The tuner can show the measured error of a reed with respect to the desired deviation from the beating list. See chapter 22, paragraph 'How the errors are calculated' for an explanation concerning this setting.

The measured errors with respect to the desired value from the beating list

In the example below the tuner shows the measured errors with respect to the desired deviation from the beating list. The tuner takes the desired deviations for the reeds of the note to tune from the beating list and shows these in dark green, right below the white value of the measured error of the concerning reed. The desired deviation from the beating list for reed 1 is in this case -14.9 Cent. The white value +2.0 Cent indicates that the reed is still 2.0 Cent too high. The deviation with respect to the exact value from the scale is therefore -14.9 + 2.0 = -12.9 Cent. The red needles at the bottom always give the errors of the reeds with respect to the exact value from the scale. The left red needle indeed indicates approximately -12.9 Cent. This way a reed has the desired value if the white measured value indicates zero. This applies for each reed and for each note.

The measured beatings with respect to the desired beating from the beating list

The deviation of a reed is allowed to be a view Cent. The human ear is not able to observe this. The beating between two reeds is however observed much more accurate. For this reason the distance between the pitches of two reeds must be tuned more accurate then the separate reeds. If the errors of both reeds are equally too high or too low, then the beating nevertheless is good. The tuner can measure the deviation of the beating and this value can be used to tune the reeds.

In the example below the tuner shows the measured errors with respect to the desired deviation from the beating list. The tuner takes the desired beating between the reeds of the note to tune from the beating list and shows these in dark green, right below the white value of the measured beating error of the concerning reeds. The desired beating between reed 1 and reed 2 from the beating list is in this case 2.36 Hertz. The white value -1.04 Hertz indicates that the measured beating is still 1.04 Hertz too low. The text boxes at the bottom near the red needles show the absolute frequencies of the measured reeds in Hertz. The difference between the left two frequencies is 260.89 - 259.58 = 1.31 Hertz. This is indeed 1.04 Hertz (2.36 – 1.31) too low. This way the beating has the desired value if the white measured value indicates zero.

Creating beating lists

The screen, in which the beating lists can be created, can be opened in two ways:

1.       In the settings screen (Menu - Settings…), click on the button 'Edit desired beating values…'.

2.       Click on the text below the image of the accordion in the main screen of the tuner.

Beating lists can simply be created with the tuner using a table. Only a couple of beating values need to be filled in. In the beating list below all notes (E0 up to C9) are present. The desired beatings of a number of notes must be filled in to the 'Btng' column. The value can be filled in by clicking on the desired line in the table and using the keyboard to type the value. The value can be changed by clicking on the concerning value and pressing 'Enter'. The remaining columns 'Rd 1', 'Rd 2' and 'Rd 3' are automatically calculated and filled in by means of the 'Btng' column. The missing beating values, however, are calculated (interpolated and extrapolated) by means of the notes which are filled in. Whether these interpolations and extrapolations should be calculated or not can be configured with the three check marks in the middle at the top of the screen. Which of the three reeds that should be tuned on the exact value from the scale (deviation = 0) can be chosen in the middle at the bottom of the screen. The beating list can be filled in Cent or in Hertz. This can be configured in the bottom left corner of the screen. See chapter 28 for an explanation about Cent and Hertz.

A graphical overview of the beating list

The beating list is shown on the right side of the screen using a graphical overview. The columns represent the notes. The desired deviations of the reeds for each note are shown as horizontal lines. Reed 1 is red, reed 2 is yellow and reed 3 is blue. The maximum value of the graph (Max scale) is shown on the right side above the graph. This is the highest value in the graph. The zero line is in the middle and the value entirely at the bottom is also maximum but then negative. By clicking on a note (column) that note is marked with a dark green background and at the same time that note is also selected in the table on the left of the screen. The other way around, if another note is selected in the table then the marked note in the graphical overview also changes. By hovering with the mouse pointer for a moment just above a note in the graphical overview, a tool tip with the concerning note name and associated pitch in Hertz is shown.

By clicking on the 'View in Cent' button, the graphical overview is shown in Cent instead of in Hertz. The beating values do not change because of this, but the lines in the graph look differently because the values in Cent are relative with respect to the pitches of the notes concerned. A screenshot of this is shown below. If the beating list is filled in Cent then this button changes to 'View in Hertz' and its function is inverted.

Determine the beating list using the recorded notes

The beating list of an accordion is often not known. The beating list can then be determined mostly quite simple by recording all notes of the accordion and then in the screen for the beating lists creating a beating list and filling in the table. The recorded deviations of the reeds are shown in the graphical overview of the beating list when the button 'show recorded' is pressed. This is only possible if the module 'record and report' is present in the tuner. The lines in the graphical overview that represent the desired beatings can now be adapted (by adapting the values in the table) in such a way that they run through the recorded deviations as well as possible. See chapter 25 for an explanation about recording the notes.

Asymmetrical beating lists

The beatings are calculated symmetrical by default. This means that the beating between the first and the second reed is just as large as the beating between the second and the third reed. By filling in a percentage in the edit box 'Asymmetricity', the beating between the second and the third reed is raised by this percentage of the beating between the first and the second reed. This is shown in the screenshot below.

Missing parts in the lines of the graphical overview

Note in the screenshot below that a part of the blue line is missing. The blue line shows the beatings in Hertz. If the beatings are shown in Cent (like in the second screenshot below) it can be seen that in this part of the blue line the beatings are larger than 50 Cent. Such large beatings are not realistic and are not supported by the tuner.

Store and load beating lists

To be able to use the beating list it must get a name first. Enter the desired name in the text box 'Description'. Beating lists can be stored as .btg files to be loaded again later. Use the button 'Save…' to store the beating list and the button 'Load…' to load a beating list.

A beating list is loaded with the screen below.

24.    Tuning accordions

Measure the correct pitch

The pitch of a reed changes slightly if the accordion is opened (or closed). The pitch changes also if the reed block is taken out of the accordion (or placed into). If a reed is tuned outside the accordion one must take this change in pitch into account. If the reed is placed back afterwards and the accordion is closed again, then the pitch must be exactly right. To check the final pitch of a reed it must be measured when the reed is in the closed accordion again.

Measure several reeds at the same time

When a conventional tuner is used, only one reed is allowed to play at the same time during measuring. Many accordions play several reeds at the same time when pressing a key. If the accordion has no buttons with which the reeds concerned can be disabled, the accordion must be opened first to disable those reeds. Afterwards the accordion must closed again to be able to measure the pitch. With Dirk's Accordion Tuner it is possible to measure several reeds (three maximum) which sound at the same time as a result of which it is not necessary to open the accordion and disable the reeds.

The conventional tuning process

To carry out the tuning process efficiently the following steps are generally used:

1.       Open the accordion.

2.       Disable the necessary reeds.

3.       Close the accordion.

4.       Measure all notes one by one and write down the measured values.

5.       Repeat step 1 to 4 until all reeds are measured.

6.       Compare all measured values with the desired values, calculate the differences and write them down. The errors of all reeds are now known.

7.       Open the accordion.

8.       Take the reed blocks out of the accordion.

9.       Tune the necessary reeds by means of the errors written down.

10.   Tune the beatings by ear.

11.   Place the reed blocks back into the accordion.

12.   Repeat step 2 to 6 to check the tuned reeds.

The tuning process with Dirk's Accordion Tuner

1.       Measure all notes one by one and write down the errors with respect to the desired values (and the beatings as well).

2.       Open the accordion.

3.       Take the reed blocks out of the accordion.

4.       Tune the necessary reeds (including beatings) by means of the errors written down.

5.       Place the reed blocks back into the accordion and close the accordion.

6.       Repeat step 1 to check the tuned reeds.

The tuning process with the module 'record and report'

With the module 'record and report' the same steps are necessary, but nothing needs to be written down anymore and a tuning report can be printed.

25.    Tuning accordions with the module 'record and report'

The tuner can be extended with a module that can quickly record all the notes of the accordion and generate a report from that. This report gives the errors of all reeds in a conveniently formatted table. After opening the accordion, the reeds that differ too much can be corrected on the tuning table using the errors from the report.  The reeds (that have a deviated pitch outside the case) will have the right pitch after putting them back into the accordion. The report can be generated and printed again afterwards to go with the accordion as the tuning report. See chapter 24 for an explanation about tuning an accordion. With the module 'record and report' the possibility is given to create (unknown) beating lists of existing accordions. See chapter 23 for an explanation about producing beating lists.

Record the notes

The record mode of the tuner is enabled by pressing the button 'record'. The record mode only works when single notes are measured. Chords and octaves cannot be recorded. The mesh on the background of the equalizer turns red in record mode and a cursor (the red beam) appears in the left side of the equalizer. As soon as the tuner measures a stable and accurate note, the measured errors of the reeds are stored in the box of the red cursor. The word 'Recorded' then appears in the note window in red on the left side below the note character. The red cursor then shifts one box to the right. After a short period of silence the next note can be recorded. Recorded notes can be removed with the 'Backspace' of the keyboard.  By shortly hovering above a box with stored errors with the mouse pointer, a tooltip with information about the stored note, the errors and beatings appears. It is possible to record the same note several times as is necessary with most diatonic harmonicas. In the screenshot below a number of notes are recorded with two reeds (horizontal red and yellow lines) per note.

The overview of the recorded notes

The overview of the recorded notes (the tuning) is opened by releasing the button 'Record'. The overview can also be opened through 'Menu - Record and Report…'. The screenshot below shows an overview of a diatonic harmonica with two reeds per note. Instruments with three reeds per note are also possible. In the upper text box 'Tuning description', a description of the tuning must be given. This description is used in the tuning report. All recorded notes are listed in the table.

The data concerning the reeds

The data concerning the reeds are grouped by reed below the headings 'Reed 1', 'Reed 2' and 'Reed 3'. The columns for the reeds which are not recorded remain empty. It concerns the following columns:

Note  -  The name of the recorded note. The order of the recorded notes in the table is equal to the order in which the notes are recorded. The same note can appear several times.

Curr   -  The current measured error of the reed in Cent with respect to the exact pitch from the scale.

Goal  -  The desired deviation for the reed from the beating list in Cent. This column is empty when no beating list is loaded.

Error  -  The error in Cent which the reed is apart from the desired deviation. This column is empty when no beating list is loaded.

The data concerning the beatings

The data concerning the beatings are grouped per reed couple below the headings 'Beating 1-2' and 'Beating 2-3'. The columns for the beatings which are not recorded remain empty. Below the table is chosen if the values in these columns are given in Cent or in Hertz. It concerns the following columns:

Curr   -  The current measured beating.

Goal  -  The desired beating. This column is empty when no beating list is loaded.

Error  -  The error in the beating. This column is empty when no beating list is loaded.

Edit the recorded errors

The values in the 'Curr' columns of the reeds can be manually edited here by clicking on the value concerned and pressing the Enter button of the keyboard. If a value is changed, the other values of the same note are calculated again.

Stop recording

If this screen with the recorded tuning is closed with the red cross then the tuner will continue recording. Recording is stopped if there are no recorded notes left. All recorded notes are removed at once by pressing the button 'Clear'. If this screen with the recorded tuning is closed afterwards then the tuner stops recording.

The graphical overview of the recorded errors

The graphical overview of the recorded errors 'Graphical overview of the recorded tuning errors' shows the errors of the reeds per note. The notes are sorted from left to right from E0 to C9. The notes which are recorded several times fall into the same column and are all shown there. The different red, yellow and blue lines then are not clearly distinguishable from each other. By shortly hovering above a column with recorded notes with the mouse pointer, a tool tip appears with data concerning the note (name and frequency), the errors of the reeds and the beatings. If the note concerned is recorded several times then this data is shown in the tool tip several times. On the right side above the graph the maximum value of the scale (Max scale) is shown. This is the upper most value in the graph. The zero line is in the middle and the value at the bottom is also the maximum but then negative. By clicking on the column, the column is marked by a dark green background and the corresponding line in the table is selected. If the note concerned is recorded several times then the corresponding lines in the table are selected one after each other by clicking several times on the column in the graphic overview.

Store and load recorded tunings

To be able to use the recorded tuning it must first be given a name. Enter the desired name in the text box 'Tuning description' in the top of the screen. Recorded tunings can be stored as .tun files to be loaded later. Use the button 'Save…' to store the recorded tuning and the button 'Load…' to load a previously stored tuning.

With the screen below a previously stored tuning is loaded.

Edit the beating list

The screen with which the beating list can be loaded and edited, is opened with the button 'Edit desired beating values…'.

Show the desired beatings

The desired deviations from the current beating list can be shown in the graphical overview by pressing the button 'Show beating values'.

Create tuning reports

A report can be created from the recorded tuning. This report gives the error of each reed in a conveniently formatted table. After opening the accordion, the reeds which deviate too much can be corrected on the tuning table using the values from the report. The reeds which have an deviated frequency outside the case will get the correct frequency after being put back into the accordion. The report can be generated again afterwards and be joined with the accordion as its tuning report. The screen with which a tuning report can be created, is opened by pressing the button 'Report…'. See chapter 24 for an explanation about tuning an accordion.

A tuning report can be created with the screen below. The information that will be placed in the report in addition to the measured errors and the beatings must be filled in here. Company information such as name, address and place of residence of the tuner can be entered in the text box 'Company info'. The website of the tuner (URL) can be entered in the text box 'Company website'. To test the URL, the website can be opened by pressing the button 'Go'. The company's logo can be loaded with the button 'Load logo'. The following formats are supported: bmp, gif, jpg and wmf. The date that comes on the report can be changed with 'Report date'. If all information is entered, the tuning report can be created with the button 'Create tuning report'.

The tuning report is stored as an XML file. With the screen below the path is chosen, the file name is entered and the file is stored with the button 'Save'. An XSL file is also stored in the same path as the XML file. This XSL file is necessary to be able to view the tuning report (the XML file) with an Internet browser. Take care that both files remain together if the tuning report is copied to another location.

View and print the tuning report

As soon as the tuning report is stored it is opened in the Internet browser. The tuning report can be viewed again afterwards by looking it up with the Windows Explorer and then double clicking on it. The tuning report can be printed using the print function of the Internet browser. An example of a tuning report with a number of notes from a diatonic harmonica with two reeds per note is given below. Three reeds per note is also possible. See earlier in this chapter for an explanation about the columns of the table.

26.    Noise reduction and accuracy

Beside the notes that need to be measured, a lot of other undesirable sounds are measured by the microphone. These are for example sounds such as the cooling fan of the computer, a car driving by, a slamming door, a barking dog, wind etc. All these sounds disturb the measurements and for this reason are suppressed by the tuner automatically.

Background sounds

The tuner measures background sounds and determines their pitch and volume. The strength of background noise is indicated in the tuner with a horizontal green line per note. Long lasting sounds are considered as background sounds. As soon as a note (one of the blue bars) reaches out of the background sounds then the tuner can select this note to be measured. In case of an extreme amount of background sounds it is possible to enable the option 'Enh. Noise reduction' in the settings screen (Menu - Settings…). Background sounds are then extra reduced.

Slamming doors or foot steps

The low sounds which are produced by for example slamming doors or foot steps on a wooden floor are automatically filtered out by the tuner.

50 or 60 Hz hum

The 50 or 60 Hertz hum which is frequently produced by the power supply of the computer is filtered out by the tuner automatically. If an extreme amount of this type of hum is picked up by the microphone, a so-called 'hum filter' can be enabled in the configuration screen (Menu - Settings…). The tones nearby 50 or 60 Hertz are then extra reduced.

Automatic sensitivity

The sound volume of the reed to measure that is received by the tuner depends on the following factors:

1.       The sound volume produced by the reed.

2.       The distance from the reed to the microphone.

3.       Obstacles between the reed and the microphone.

4.       The sensitivity of the microphone.

5.       The sensitivity of the sound card.

6.       The Windows volume settings for the microphone input.

To make the tuner work under all circumstances, the incoming signal is amplified to a standard level automatically.

Higher sensitivity in the manual selection mode

In manual selection mode (see chapter 15) the tuner only pays attention to one note at the same time as a result of which there is less chance on disturbing sounds. In this mode the tuner's sensitivity is increased so softer sounds can also be measured.

27.    The accuracy of the tuner

The maximum accuracy in Hertz and in Cent

The accuracy of the Accordion Tuner is better (less) than 0.05 Hertz (waves longer than 20 seconds). The accuracy in Cent gradually changes over the range of the tuner because a Cent is a relative unit. The interval (the width) of a note in Hertz increases as the pitch gets higher and the width of a note in Cent is by definition (always) 100. Some values of the accuracy of the tuner in Cent: C1: 2.6 Cent, C2: 1.3 Cent, C3: 0.7 Cent, C4: 0.3 Cent, C5: 0.2 Cent, C6: 0.08 Cent, C7: 0.04 Cent, C8: 0.02 Cent, C9: 0.01 Cent. So in Cent, the tuner gets therefore more accurate as the pitch gets higher. See chapter 28 for an explanation about Hertz and Cent.

Detectable pitch differences

The smallest by human ear detectable pitch difference is approximately 2 Hertz. The accuracy of the tuner of 0.05 Hertz is many times better. This high accuracy is necessary to measure the beatings between two reeds. A difference in beating of more than approximately 0.1 Hertz is already detectable by the human ear.

Accuracy of the measured beating

The accuracy of the measured beating is better (less) than 0.1 Hertz. The smallest measurable beating is approximately 0.6 Hertz. The largest measurable beating is limited because both tones must be in the range of the same note.

Automatic calibration

The tuner uses the sound card for its measurements. To compensate possible errors in the sound card, the tuner carries out an automatic calibration. Manual calibration such as those often possible on conventional tuners (with a screw for example), is not necessary. Because of this the measurements of the tuner are always accurate enough.

The internal accuracy

The tuner shows the measured errors with 1 or 2 decimal places (digits behind the comma). The tuner calculates with 7 decimal places internally. Right before an error is shown, it is rounded on 1 or 2 decimal places.

Influences from outside

Beside the accuracy of the tuner itself, the following influences from outside must be taken into account:

1.       The pitch of a reed changes if the accordion is opened and changes back if the accordion is closed again.

2.       The pitch of a reed changes if the reed block is taken out of the accordion and changes back if the reed block is put back in again.

3.       The pitch of a reed decreases as the bellow pressure increases. The amount of beating between two reeds virtually does not change because both reeds decrease equally.

28.    Hertz and Cent

A tone which exists of exactly one frequency looks like a sine wave:

Hertz

The pitch of such a tone is expressed in Hertz: the number of waves per second. In the figure above two waves are shown.

Cent

The notes in the scale (equal temperament) increase in frequency. Every octave exists of 12 notes (semitones) and corresponds to a doubling in frequency. The A4 is 440 Hz and the A5 880 Hz. The frequency range (width) of a note is therefore larger if the pitch is higher. The A4 runs from 428 up to 453 HZ and the A5 runs from 855 up to 906 Hz. The width of a semitone is by definition (always) 100 Cent.

The ratio between Cent and Hertz

The width of a tone in Hertz increases as the pitch increases. The width of a semitone in Cent is always 100. The difference in Cent ∆ between two tones with frequencies f1 and f2 (in Hertz) can be calculated as follows:

∆ = 1200 log₂ (f1 / f2)

If the frequency difference (f2 - f1 in Hertz) increases linearly then the difference in Cent increases logarithmic.

The deviation of a measured tone in Cent

If the tuner shows an error of a measured tone in Cent, then an error of 0 Cent means that the tone is exactly right. If the deviation is -50 Cent then the measured tone is exactly in the middle of the desired tone and the previous semitone. If the deviation is +50 Cent then the measured tone is exactly in the middle of the desired tone and the next semitone.

29.    Beating

Beating occurs when two tones with a small pitch difference are played at the same time. The waves of both tones then add up and influence each other. At some moments they amplify each other and at other moments they weaken each other. In the figure below, two tones (f1 and f2) with a small frequency difference are shown. In the bottom wave both tones are added up (f1 + f2). The occurring beating by the alternating amplifying and weakening of the combined signal is clearly visible. The frequency of the beating is exactly equal to the difference of the two tones (f2 - f1).

Beating of octaves

When two tones that lie approximately an octave apart from each other are played at the same time beating can also occur. In that case beating occurs from the addition of the higher octave and the first overtone of the lower octave. These are again, just like with 'ordinary beating', two frequencies which lie near at each other.

30.    The equal temperament

The tuning or temperament of a scale is the way the frequencies of the notes are chosen. In Western music the equal temperament is most popular. Other temperaments are for example: the just intonation, the Pythagorean tuning, the mean tone temperament, the well temperament and the 31 equal temperament.

An octave is divided into 12 'proportionally increasing' distances. The ratio of the frequencies of two successive semitones is always the same (approximately 1.0594631). Because of this, all intervals (second, third, fourth, fifth, sixth, seventh), except the octave, deviate from the just tuning. They cause beating. All equally named intervals sound equally false (they beat). The advantage of this tuning is that it remains the same when switched to another tone type (a number of semitones higher or lower), and it is therefore not needed to tune the instrument differently.

Below an overview is given of the intervals and the differences of the equal and the just temperament. The just temperament is the way to construct a scale where the frequency ratios are simple integers. This produces music which is experienced as pure (not false).

31.    An overview of the screens

1.       Input signal          -  The currently measured signal. See chapter 10.

2.       Equalizer             -  The volumes of all notes. See chapter 11.

3.       Note spectrum     -  The frequency spectrum of the detected note. See chapter 13.

4.       Beating list           -  The name of the selected beating list. See chapter 23.

5.       Note letter            -  The detected note. See chapter 12.

6.       Reed deviation    -  Numerical display of the reed deviation. See chapter 14.

7.       Beating                -  Numerical display of the beating. See chapter 14.

8.       Reed deviations   -  Graphical display of the reed deviations. See chapter 14.

32.    An overview of the buttons

-          Hz / Cent    -     Switch the beating screens (7) between Hertz and Cent. See chapter 9.

-          Record       -     Start recording multiple notes, open the report screen. See chapter 25.

-          Sound        -     Play the selected note. See chapter 17.

-          Octave        -     Increase or decrease the selected note by one octave. See chapter 15.

-          Note           -     Increase or decrease the selected note by one semi tone. See chapter 15.

-          Auto           -     Switch between automatic and manual detection. See chapter 15.

-          +                -     Increase the frequency of the A4. See chapter 19.

-          -                 -     Decrease the frequency of the A4. See chapter 19.

-          Menu          -     Open the menu with extra functions in the upper left corner of the tuner.

-          Octaves      -     Measure octaves. See chapter 21.

-          Chords       -     Measure chords. See chapter 20.

-          Reeds        -     Configure the number of reeds to measure. See chapter 9.

-          Freq           -     Turn the three little frequency screens in the bottom on or off.

-          Trans          -     Transpose. See chapter 18.

-          Freeze       -     Freeze the Tuner. See chapter 9.

33.    Shortcut keys and clicks

Shortcuts on the keyboard

-          Left arrow                   -  Decrease the selected note by one semi tone. See chapter 15.

-          Right arrow                 -  Increase the selected note by one semi tone. See chapter 15.

-          Spacebar                   -  Freeze the tuner. See chapter 9.

-          Enter                         -  Record a note that is not (yet) locked. See chapter 25.

-          Backspace                -  Remove the last recorded note. See chapter 25.

Clicks on screens

1.       Click on the input signal screen to open the settings screen. See chapter 22.

2.       Click on a column in the equalizer to select a note in manual selection mode. See chapter 15.

3.       Click on the name of the beating list to open the screen where beating lists can be created, loaded and edited. See chapter 23.

34.    Frequency table of the notes

The table on the next page gives an overview of the frequencies of the notes which are supported by the Accordion Tuner. These are the notes from the equal temperament.

The table exists out of the following columns:

Semitone number    -  The number of the semi tone

Note name              -  The name of the note

Note octave            -  The octave of the note

Note frequency       -  The note’s frequency form the scale in Hertz.

Note width               -  The width of the note in Hertz.

Accuracy                -  The accuracy of the tuner for this note in Cent.

35.    System requirements.

The Tuner runs optimally on machines starting from the Pentium II, 1 GHz. On less fast machines the tuner also works fine, but will react more slowly. The tuner runs under Windows 2000, XP, Vista and 7 and uses a microphone input. See chapter 7.