Daqarta
Data AcQuisition And Real-Time Analysis
Scope - Spectrum - Spectrogram - Signal Generator
Software for Windows
Science with your Sound Card!
The following is from the Daqarta Help system:

Features:

Oscilloscope

Spectrum Analyzer

8-Channel
Signal Generator

(Absolutely FREE!)

Spectrogram

Pitch Tracker

Pitch-to-MIDI

DaqMusiq Generator
(Free Music... Forever!)

Engine Simulator

LCR Meter

Remote Operation

DC Measurements

True RMS Voltmeter

Sound Level Meter

Frequency Counter
    Period
    Event
    Spectral Event

    Temperature
    Pressure
    MHz Frequencies

Data Logger

Waveform Averager

Histogram

Post-Stimulus Time
Histogram (PSTH)

THD Meter

IMD Meter

Precision Phase Meter

Pulse Meter

Macro System

Multi-Trace Arrays

Trigger Controls

Auto-Calibration

Spectral Peak Track

Spectrum Limit Testing

Direct-to-Disk Recording

Accessibility

Applications:

Frequency response

Distortion measurement

Speech and music

Microphone calibration

Loudspeaker test

Auditory phenomena

Musical instrument tuning

Animal sound

Evoked potentials

Rotating machinery

Automotive

Product test

Contact us about
your application!

Getting Started With Pitch Track

There are a lot of steps required to get everything set up for Pitch Track operation. The following instructions assume you are a new user, so just take your time and follow along step by step. Your settings will be automatically saved for the next Daqarta session, so you won't have to go through this whole process again. If you are already a Daqarta user, but just new to Pitch Track, you should still follow along to make sure you understand the Pitch Track requirements.

Refer to Basic Input Operation - Your First Input Signal to get a microphone or other signal visible on the Daqarta display. With the actual signal you intend to use (singing, whistling, instrument, or whatever), adjust the Input Line and Input Master levels, as well as any external preamp, microphone position, etc, so that the loudest peaks are somewhat less than full-scale at the default display magnification.

You don't need an expensive microphone for Pitch Track, since you are not trying to record the signal with perfect fidelity. In fact, it's not usually a problem if you overdrive the input so that the signal clips... you may even want to do that deliberately, to boost the fundamental component if it is missing or weak.

In general, you should try to position the microphone close to the sound source, to pick up more of the desired signal relative to any background or room noises. At greater distances, a unidirectional or noise-cancelling microphone may be helpful. Built-in laptop microphones may cause problems by picking up keyboard noises, or the sound output from the built-in speakers.

If the input signal is a human voice with plosive pops and sibilant hisses, you may get better results with the microphone at a 90 degree angle to the breath direction, while still close to the lips... across the microphone, not directly into it. This is especially important with whistling.

Once you have a signal, click Spectrum on the toolbar, and then click on the thin horizontal button below it to open the Spectrum Control Dialog. Make sure that Y-log is active so that the spectrum Y-axis shows dB. Click on the Window button to apply the default Hann window function, which will sharpen the peaks on the trace.

Your input signal will show the biggest peaks at the low (left) end of the spectrum. To expand that region for easier viewing, toggle X-Axis on the toolbar, then click the thin button below it to open the X-Axis Dialog. Set eXpand Max to about 2500 Hz, which will cover most voice and instrument ranges.

Now go back to the Spectrum Control Dialog and click on Peak. Then click on Track to open the Spectrum Track dialog, and toggle Track on in that dialog. The solid cursor (vertical blue line on the spectrum) should start to dance back and forth, and the position readout (box below the trace display, near the left end) will turn pink to indicate that the cursor is under automatic control.

You now must set the Track Threshold so that spectral peaks of musical notes are tracked, but not random noise, hum, or background sounds. Observe the height of the desired musical signal peaks, then stop singing or playing and observe the height of any unwanted peaks when no musical input signal is absent. Set Threshold to be larger than the unwanted peaks, but less than the softest desired peak.

In general, the Threshold setting will be a trade-off between false notes when you set it too low, and missed notes when you set it too high. Your playing or singing technique will have a big effect here: Clean signals with a consistent level are best.

Also note the frequency range of the desired signal, and set the Track Max and Min Frequencies to include that range, but not a lot above or below it. (The default is probably OK to start with.) That will help to reduce the effects of interfering background signals, as well as breath or unwanted instrument sounds.

Toggle Fundamental on. This is not always needed for whistles, flutes, or other pure-tone sounds, but it usually doesn't hurt... and it is very much needed for voice and other harmonic-rich sounds, especially struck or plucked strings like piano or guitar.

Now click on the Sgram/PT button in the main toolbar, and the thin Spectrogram / Pitch Track control dialog button below it. You should see a colorful spectrogram display of your input signal, complete with all harmonics and unwanted background noise. (By default the spectrogram shows the full unexpanded frequency range, so if you want to play around with this view you should toggle the eXpand button and adjust the eXpand Max and Min controls as desired. But that's not needed for Pitch Track, which has its own default range...)

Click on Pitch Track. The screen background will look somewhat like a keyboard, with notes labeled on the Y axis. The input signal appears as a single thin line at the fundamental pitch. The color is proportional to loudness, as shown by the color bar at the right edge of the trace area.

You will probably want to toggle the Trigger button off on the main toolbar, so that the pitch trace advances at a constant pace, even in silence.

The Trace Update interval in the X-Axis dialog controls how fast the pitch trace sweeps across the screen, and also affects response speed. Leave it at the default (10 msec) for now.

You may want to adjust the eXpand Max and Min controls to better center your playing range in the display. The Wide button can make the pitch line more visible, and the Notes button can be toggled to Freq so the Y axis can be easily compared with eXpand frequencies. The Track Limits button opens the same Spectrum Track dialog as before, in case you want to adjust the threshold or frequency limits. You may also want to try a different window function instead of Hann, such as Hamming.

Congratulations, you now have basic Pitch Track working! If you just want to view and analyze your voice or instrument pitch, this may be all you need.

However, if you want to use your voice or other input signal to play a MIDI instrument, see Getting Started With Pitch-to-MIDI.


See also Pitch Track Toolbox - Overview, Spectrogram / Pitch Track Controls, Spectrogram / Pitch Track (Sgram/PT)

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