Recently I downloaded and purchased an APP called “AudioTest.” For $4.99 you get a complete test tone generator for your Mac (sorry no PC yet). It can make sine, triangle, sawtooth, square, pulse, smooth sawtooth, smooth pulse, and smooth square waves as well as white, pink, brown and gaussian noise. You can also control the sample rate from 44.1 to 192, 16 or 24-bit depth, and whether you send a stereo or mono signal.
Other built-in features in AudioTest include being able to adjust the time of generated test tones from .01 second to 300 seconds, or you can check the “continuous” box. You can also change output devices virtually on the fly in AudioTest, just as if you had a Sound Control box always open. Of course you can use either fixed frequency test tones or designate a sweep where you can also adjust the start and stop points. If you want to test for phase you can shift the test tones from -180 degrees to +180 degrees. You can even adjust the output level of your test tones from -0 dB to -96 dB. If you wish, you can make the test tone volume increase or decrease by a predetermined amount, such as 10 dB. Obviously, AudioTest makes matching output levels between two DACs a snap. Finally, AudioTest has a very accurate meter than can measure peak, average, or RMS output levels.
I’ve been using AudioTest for a little over a week and I have nothing but good things to report. It is remarkably stable, all the controls work properly, and it is flexible enough to allow for a wide variety of tests. I’ve found AudioTest especially useful when auditioning headphones. First I use the white and pink noise for break-in and then I run some sweep frequency tests to determine where the earphones noticeably diverge from a flat frequency response. After a couple of wide range sweeps AudioTest lets me narrow down anomalies by doing more limited sweeps of as little as 20 and 30 Hz increments.
If you have ever had the urge to test your speakers, headphones, or even DACs, for the princely sum of $4.99 AudioTest, will put you in control.