Test your soundcard for clipping, with this sample Options

[Jan S.]

For everybody fighting with occasional clipping (or perfectionists wanting to test everything) you should try the attached sample, udial.

Testing:

• play the sample in your favourite player (decoded or not, having disabled all DSPs and EQs that can interfere)
  
• if the output sounds weird at any time you should:
  • lower the output vol. in your soundcard config (should be the speaker icon in your system tray).
  • For some soundcards 48kHz is better (audigy 2 etc.).
  • lower the vol. till the sample doesn't sound weird at any time.

The output will sound really weird if your settings clip.
Your output can occasional clip without you knowing/hearing it. But for us perfectionists this will theoretically give a better quality output.

ATTENTION: Play this sample at a low volume anytime, even if you hear nothing special! It can be very harmful to equipment and/or your ears.
It's strongly recommended to use some very cheap (PC) speakers if you want to test this,
otherwise you might really ruin your tweeters (it has happened several times already).

Attached File(s)

 udial.zip ( 217.55K ) Number of downloads: 19622

 

[JonPike]

Hmmmm....  now Fubar .60 is wierd.. I get heavy "laser blast" sound effects on every one I tried,  (using DS and resampler, and no other DSP) except 32Khz!! Even Audigy native 48Khz rate had bad noise.  What's going on here?

Guess I'll be irritating and say, "Hey, I'm sticking with Winamp,  for better sound!!"  };-)    Though it is Peter's earlier SSRC code.

You just haven't set up Foobar2000 adequately to cope with this sample (i.e. you've set it up to permit clipping) - and an imperfect setup is one thing this sample helps identify.

As mentioned above, you need to turn on Foobar's clipping prevention (Preferences/Playback/ReplayGain box) because the Replaygain is trying to boost this above full scale, seeing as the dial-tones are very quiet and the full scale ultrasound is inaudible. Replaygain causing clipping is very rare (esp in Album Gain mode). You can turn it off again after the test if you're want to let it clip.

The other (less likely explanation) is that you have soft clipping limiter turned on, and that's causing distortion (as it is supposed to) or you're running some other compressor/limiter DSP (except for Advanced Limiter which only distorts the signal when clipping will occur - it knows this by reading ahead by a number of samples) or are running a pre-amp or equalizer with positive gain values.

From what you say about Winamp, it sounds like you then simply need to set FB2K's resampler active in the DSP list (usu. at the top of the list of DSPs) and set it to 48000 S/s for your Audigy 2.

Then FB2K will sound fine.

Using the SSRC, you also have a good Winamp setup if you don't use the dodgy Winamp EQ, and probably couldn't tell the difference from FB2K in a blind listening test, unless you had very good equipment and environment or have tracks for which Winamp doesn't support Replaygain.

OK... turning off Replaygain killed the laser noises. Is this what you mean by "turning on Foobar's clipping prevention"?

I never changed it before, it was set to "use album gain" and "use peak info..." checkbox was checked. Isn't the checkbox feature supposed to detect the highest peak and then use that as a maximum? It can't detect a 19Khz (or whatever that high tone is) tone?

I had no other kind of limiter or other DSP, just the Attenuator (don't know what this is, if not the volume control) and the Resampler, which I did have set to 48Khz for most of my tests, since I have a Audigy 1.

So, I guess Foobar's problem was completely caused by Replaygain scaling the track wrong..

Hmmm... thought I'd check this out by running no resampling and no replay gain to see the different effect of clipping and bad resampling, and Foobar just locked up.. Ok, no resampling is similar, laser sound but quieter and raspier, then with the replaygain changing it.

Only question I'm left with, is Replaygain supposed to catch a file like this and use the peak info to rescale when the first pass at it still causes clipping, like the checkbox mentions?

Maybe a second question, did Peter ever make a resampling version past 2.2.2.3 for winamp2? Not that I apparently have any problems with that one...

I do noitce that Foobar now puts up the playing file when you're listening to a Shoutcast station, but I'm still a sucker for the quick link to the homepage, and etc that you get with Winamp..