Find out if there's something wrong with your computer source setup

Halcyon pointed this out in another thread, but I thought it was important enough to deserve its own thread.

Do you use a computer source? Are you unsure if your current hardware/software/drivers are delivering a clean output signal? Here's a test you can do that doesn't require any special effort and seems to be very effective in pointing out problems in people's systems. This test is particularly good at demonstrating problems caused by resampling (whether from cheap Creative hardware, KMixer, or poor resampling plugins), and high-frequency intermodulation distortion from the hardware itself, and clipping and requantization errors caused by poorly written or configured plugins (advanced limiter, replaygain, etc.).

The test is simple. Go here:
http://www.hydrogenaudio.org/index.p...=post&id=98252
or here if the above link doesn't work:
http://www.hydrogenaudio.org/index.php?showtopic=9772
and download the sound sample. Play it back with whatever settings you would use to play back normal music (resampling, replaygain, advanced limiter, etc.) but disable the equalizer and crossfeed if you're using either of those. Do not try this with speakers. There is a lot of high-frequency energy in the signal and it could damage your tweeters if the volume is too high.

If you hear telephone sounds, everything is fine. If you hear anything else, including:
1) ambulance or siren or "alien" rising/falling type sounds
2) modulated noise
3) distorted tones (clipping)
then there is something wrong with your setup.

If something in the signal path is distorting this track, you can bet it's also happening subtly when you play back music.

Please report back your results.

Edited by mod: This sound file has caused some members listening discomfort, and it should be used only with the maximum amount of caution.

By the way, if your hearing is very good and you turn up the volume enough, you may also be able to hear a faint high-pitched sound (around 20kHz). This is normal.

The problem sounds, if they occur, are much more obvious.

Hmmm, I'll convert it to WAV and post it somewhere later this evening so the Windows Media Player guys can try it. (If anyone else has the time to do it before I get around to it, please go ahead!)

This works in Foobar and WinAmp as long as you have the Monkey's Audio codec installed. There is also a FLAC version of the file linked to later on in the HydrogenAudio thread, but it is difficult to download and won't play in WMP either. Anyway, WMP users, hold on until I get the WAV version up. It's wouldn't be worthwhile to run this test with a program that you don't normally use to listen to music.

It's perfectly clean on the M-Audio Sonica with the 1.2.05 drivers as well. I have nothing in my Foobar DSP pipeline (no resampling, etc.) and output is set to 16 bit, no added dither.

A lot of the bad press surrounding KMixer is misinformation. The problems seem to be caused by bad interactions between KMixer and hardware drivers, not KMixer itself. For instance, I can't prevent KMixer from resampling the bitstream when I use the Sonica with the 1.2.20 drivers, but the older 1.2.05 drivers produce perfectly clean output.

Interesting that the first few respondents here have reported no problems. The results in the HydrogenAudio thread are a lot different -- the majority of the people there seem to be reporting problems. This might confirm what I've always suspected, that Head-Fiers care more about sound quality than the HydrogenAudio guys, who pay lip service to sound quality but really just like saying "X doesn't matter," even when obvious tests like this one show pretty blatant results on some cards (e.g. Creative).

I said not to try this with speakers! You're lucky you didn't fry your tweeters. Your headphones should be fine though.