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-to-MIDI

See Getting Started With Pitch Track before proceeding here.

Once you have basic Pitch Track working, and you can see the pitch trace on the screen, click on the Pitch-to-MIDI button (at the bottom of the Pitch Track dialog) to open the dedicated Pitch-to-MIDI dialog.

At the bottom left of the dialog click Load Setup and select !NewSetup.DQM from the top of the list. This is a default or "blank" setup with only Voice 1 selected, and all instruments set to 0 (Acoustic Grand Piano). You may want to select a continuous-tone instrument such as Hammond Organ (16), Violin (40), Trumpet (56), Clarinet (71), or Flute (73). See the General MIDI Instrument list for more options.

From the top of the Pitch-to-MIDI dialog select the MIDI Device you want to use, if you have more than one. Toggle Tempo Voice off (to use the natural tempo of your sound input), then click the Pitch-to-MIDI On/Off button to get started.

You should hear MIDI sound in response to input sounds. If not, right-click the Windows Mixer (the small speaker icon in the system tray) and select Open Volume Control. Make sure Master Volume and SW Synth are unmuted and their sliders are up.

The default device for most sound cards is the Microsoft GS Wavetable Software Synthesizer. This can create adequate sounds (subject to personal taste), but has the unfortunate problem that it is very slow to respond (high latency). For each note played, the sound comes out about a tenth of a second later... way too slow for live performance.

If that's all you have right now, go ahead and give it a try. It is still great fun to play around with. But to get low latency you will probably want to use a real hardware synth, or at least a much faster software synth. Fast "soft synths" may require special drivers so Daqarta can control them... see the discussion under MIDI Device.

Low latency is important for two reasons: The slow GS response (high latency) makes it hard to play the proper notes, even with a keyboard, since what you are playing is so far out of sync with what you hear.

But beyond that, even with a fast synth it is quite difficult to create clean voice or instrument sounds that Pitch Track can use to operate the MIDI synth. You will need to learn to control your sound very precisely, which requires moment-to-moment self-monitoring to learn. It is too hard to adjust your playing, whistling, or singing style for optimum performance when you can't hear the instantaneous effects of your control efforts.

You will probably want to play the MIDI sound through headphones, at least at first. Otherwise, the MIDI sound will be "heard" by the sound card and treated like your intended musical input signal. This produces a feedback phenomenon that is analogous to the howl or squeal you get when a microphone is too near a speaker, but the difference here is that the MIDI sound is discrete notes. The effect sounds like a troop of monkeys hammering on a keyboard, or sometimes one monkey who alternates between just two notes. (But see KaleidoSynth - an Audio Kaleidoscope for another take on this.)

So, wait until you are getting decent results with headphones, before you try to use speakers. When you do, you can sometimes minimize the feedback problem by setting the +/-Note control in the Voice Setup Dialog so that the MIDI sound is an octave or more higher or lower than the desired input, and adjusting the Track Max and Min Frequencies so that only the desired sound is tracked.

You can also use the same methods that work to reduce conventional feedback howl: Make sure the speakers are pointing away from the microphone, and make sure the microphone is as close to your mouth or instrument as is practical. If you can't get close enough, a directional or noise-cancelling microphone may also help.

Make sure Trigger is off. You may want to play around with Trigger and the various options in the Trigger Control dialog at a later time.

The default Pitch Track trace attempts to show the input signal pitch as it really is. If you toggle the Steps button On in the Pitch Track Toolbox, you instead see the pitch as seen by the Pitch-to-MIDI process: The input pitch is "quantized" to the nearest exact keyboard note.

However, when the input signal is right on the boundary between two notes, small variations (like vibrato) can cause the tracked pitch to jump back and forth from one note to the other, resulting in a series of notes where only one is intended. The Hysteresis control makes the pitch "sticky", so that vibrato is less of a problem... a wavering pitch is still regarded as the initial note unless it strays farther than the specified fraction of a semitone. A setting of 0.500 is a good place to start. (This stickiness pertains only to pitch changes, not loudness... notes still go off properly when the sound goes below the Spectrum Track Threshold.)

The Trace Update interval in the X-Axis dialog controls how fast the pitch trace sweeps across the screen, and also affects the response speed of the Pitch Tracker. You may also want to experiment with faster or slower sample rates.

Note that the default Pitch Track trace shows the input notes that are being tracked, not the MIDI notes being played. Those may be quite different, depending on the Voice Setup you use. To see the MIDI notes, click the Pitch Display button from its default "Show Tracked Pitch" to "Show MIDI Note / Vel". (The next click takes you to "Show MIDI Note / Inst", which shows different MIDI instruments as different colors. You probably don't need that until you have a multi-voice setup.)

Also, note tracking (and hence the speed of note display) may be much faster than the played rate, especially if Tempo is active. For example, Trace Update is typically set to 10 msec, which is equivalent to a Tempo of 6000 BPM. If you set Tempo to (say) 600 BPM, only one-tenth of the tracked notes will be converted to MIDI notes.

The Hamming window function may be better than Hann for some sounds. Don't use the Flat-Top window for any Pitch Track operation... it is a special-purpose window for Swept Frequency Response measurements.


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

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