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

Signal Generator
(Absolutely FREE!)

Spectrogram

True RMS Voltmeter

Sound Level Meter

Frequency Counter

Period Counter

Event Counter

Spectral Event Counter

Waveform Averager

Histogram

Post-Stimulus Time
Histogram (PSTH)

Macro System

Multi-Trace Arrays

Trigger Controls

Auto-Calibration

Spectral Peak Track

Direct-to-Disk Recording

Accessibility

Applications:

Frequency response

Distortion measurement

Speech and music

Microphone calibration

Loudspeaker test

Musical instrument tuning

Animal sound

Evoked potentials

Rotating machinery

Vehicle pass-by noise

Product test

Contact us about
your application!

Distorted Sound Output

In order to simplify diagnosis, it is best to use the default Generator setup of a simple 440 Hz sine wave. If you have changed your setup, please go to Restore Default Generator Setup before you proceed here.

The most common form of distortion is clipping, which is where the sound system is overdriven; it is trying to produce a sound that is louder than its capabilities. The tops and bottoms of the waveform will be chopped off or "clipped" at the maximum and minimum voltages the system can produce. If this happens to a pure sine wave, it starts to sound "buzzy", more like a square wave. (When driven hard enough, a sine wave can look very much like a square wave.)

The first thing to check is that you are not asking Daqarta to create a waveform that exceeds the digital limits of the 16-bit number system. If the distortion goes away when you use the default Generator setup at the same volume settings, the problem setup most likely had more than one Stream active on the same channel, with the total Level adding up to more than 100%.

If you still hear a buzzy sound, the next thing to investigate is whether the mixer is overdriving the sound card amplifier, or, if you are using an external amplifier, if the sound card is overdriving that. You might even be overdriving the speakers or headphones, which have mechanical limits similar to the electrical limits of amplifiers. Use the Daqarta volume (Vol) sliders to reduce both Master and Wave levels to see if this reduces the buzz. Many cards distort if one or both of these controls are at maximum.

Another possibility is that you are driving headphones or unpowered speakers from a Line output that has limited power. If this is the case, you can still usually reduce the volume to a point where it is undistorted, but it may be too soft to be useful. Look for a Spkr output instead, or try using an external amplifier.

If that doesn't eliminate the distortion, you may have a defective sound card, external amplifier, speaker, or headphones.

GO:

Questions? Comments? Contact us!

We respond to ALL inquiries, typically within 24 hrs.
INTERSTELLAR RESEARCH:
Over 25 Years of Innovative Instrumentation
© Copyright 2007 - 2008 by Interstellar Research
All rights reserved