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!

Multi-Channel Test Setup

The 8-ChanTest.GEN Generator setup is included with Daqarta. You can load it and use it directly, or modify it as desired.

This setup provides 8 distinctive output signals, one on each channel, to help you get your system set up properly. This can be useful because sound cards do not all adhere to the same standards of which channel goes to which output connection, under which conditions.

For example, if you don't have a multi-channel card, but you use this multi-channel GEN setup, all channels should be combined into normal stereo. But some stereo-only sound cards omit the Low Frequency (Bass) channel, even though they include Center (which is paired with it).

Also, multi-channel cards require configuration for 2-channel (Stereo), 4-channel (Quadraphonic), 6-channel (5.1) or 8-channel (7.1) mode. (See Multi-Channel Sound Card Configuration for details.) Some cards may have different ideas about which of the 8 channels should go to which output jacks in each mode. In addition, when presented with more signals from the Generator than they were configured for, they may combine the "extra" channels in certain ways.

To help you sort out these issues, 8-ChanTest.GEN provides the following signals, labeled here with the standard Windows names that are used in Daqarta's Multi-Channel Outputs dialog:

Front Left: Left Stream 0 using 440 Hz Triangle wave, with Frequency Modulation (FM) having +/-50 Hz deviation at a 1 Hz modulation frequency.

Front Right: Right Stream 0 using 880 Hz Sine wave, with FM having +/-50 Hz deviation and a 2 Hz modulator.

Center: Left Stream 1 using 1000 Hz Sine wave in 100 msec (Burst High) tone Bursts at 4 / second (250 msec Burst Cycle).

Low Freq: Right Stream 1 using 300 Hz Sine wave in 200 msec Bursts with an 800 msec Cycle.

Back Left: Left Stream 2 using White noise source in 100 msec Bursts at 5 / second (200 msec Cycle).

Back Right: Right Stream 2 using White noise source having two 100 msec Bursts (Train Count = 2) with 100 msec spacing (200 msec Burst Cycle), followed by 700 msec delay (1 sec total Train Cycle) between burst pairs.

Side Left: Left Stream 3 with stepped-frequency Sine wave running from 220 Hz up to 880 Hz in 12 two-semitone steps (Exponential step mode) at Length = 200 msec per step.

Side Right: Right Stream 3 with stepped-frequency Sine wave running from 880 Hz down to 440 Hz in 12 single-semitone steps at 100 msec per step.

Each of the signals has Stream Level set to 25%. This allows you to run this setup without clipping on a sound card that has only stereo outputs; the four Left streams will be summed to a single Left Out signal with peaks at 100%, and likewise for the four Right streams.

One way to use this setup is to plug a pair of normal stereo headphones into each output jack in turn. While listening, go to the Multi-Channel Outputs dialog and toggle the individual Left or Right Streams buttons off and on for the indicated channels; if you don't hear a change, try toggling a different channel, or plugging the headphones into a different jack.

For example, if you are plugged into a jack marked 'Rear' but you don't hear any change when toggling Left Stream 2 of Back Left or Right Stream 2 of Back Right, you can try toggling Left Stream 3 of Side Left and Right Stream 3 of Side Right, and so on. Alternatively, try the same Back toggles while plugging into other jacks until you find one where you hear changes.

Note, however, that since some channels may be combined by your sound system, such as Back and Side being combined when using this 8-channel setup on a 6-channel (5.1) card or driver mode, the mere detection of change doesn't mean that you've unambigously identified the one and only jack for the selected channel; you may need to verify that you do not hear any change when plugged into other jacks.

If you are using one of the multi-channel cards covered under Sound Card Performance Tests (CM6206 5.1 or 7.1, or ASUS Xonar U7), please check the relevant section there for details on various quirks that depend on Windows version or driver configuration. Even if your card is not one of those tested, you might find clues to unsuspected behavior of your own card.


See also Multi-Channel Output Controls, Signal Generator Control Dialog.

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