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Test your soundcard for clipping, with this sample
Jan S.
post May 26 2003, 19:57
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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)
Attached File  udial.zip ( 217.55K ) Number of downloads: 20739
 
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DickD
post Jun 3 2003, 11:34
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Thanks for the informative reply, Garf. I'll go back and edit my previous post to mention your detailed knowledge. It's comforting to know you thought of such extreme possibilities as dither causing clipping and designed to avoid them.

I haven't been able to test this myself because the machine I'm on right now doesn't support 48000 Hz. I have actually tested it using Microsoft Sound Mapper, which generates sirens, and didn't get a pop-up warning (I never have been warned of clipping because I use Advanced Limiter as well as RG).

I guess JonPike may have something else causing the warning. The only things that spring to mind are other DSPs. I know that the new Equalizer can have positive values, and the defunct PreAmp could too.

Ah, using diskwriter, 64-bit floating point, resampled to 48000 S/s with DSP enabled (Resampler 48000 S/s, fast, 32bit) AND with ReplayGain enabled (with clipping prevention), the WAV created, when scanned for RG, has:

Track Gain = +18.190000 dB (correctly reflecting 0.02 dB gain applied with clipping prevention)
Track Peak = 1.000086

That is clipping, but only just, and inaudibly so. The 64-bit floating point WAV output is the same as the internal chain contains just before it dithers down to the playback format.

JonPike's clipping prevention followed by resampler presumably also generated this value. This is the sort of behaviour one might expect from a Resampler because it incorporates a filter. Any filter can cause differing peak values, as can a change of sampling rate.

The same method but with Slow resampling (but still only 32 bit precision), does not clip.

Resampler: 48000 S/s, Slow Mode, 32 bit precision:
Track Gain: +18.190000 dB
Track Peak: 0.999928

So, it's the precision of the long resampling filter window in Slow mode that makes it work more precisely in terms of peak amplitude. There's no audible difference in Fast mode, however.

So it's the combination of Fast mode resampling and ReplayGain going to the clip-prevention limit that generated the clipping warning.

So, JonPike, if you have the processor speed to spare, you could use slow resampling mode, but for sound quality, it's negligibly different, and Fast mode will sound just great. In real music, with Album Gain turned on and 89.0 dB RG target volume, you'll probably never see that warning message again.

There's no need to change your usual settings for real music because the minuscule clipping that did occur was inaudible to you, even on such an extremely sensitive test sample as this, but Slow mode resampling will give that final assurance of the utmost possible quality (albeit that it's inaudible). In real music with Album Gain, the warning message is extremely unlikely to ever be generated.

The only thing one could plausibly wish to add to the ReplayGain interface in FB2k is the facility to specify that RG's 'use peak values' feature could have a margining facility to enable the most pernickety users to ensure that full dither is applied and their resampler will not clip ever. An option of normalising the Album/Track to 0.999000 instead of 1.000000 if the respective album peak or track peak value would cause clipping ought to be sufficient for anyone using 16-bit audio or above, and would leave sufficient headroom for both 16-bit strong ATH noise shaping dither and fast resampling to 48000 S/s to hit their worst peaks simultaneously.

I do appreciate that it's almost certainly inaudible, except when the peak value is ultrasonic and the dither is required for audible sound sinking into the noise floor, so the lack of dither and lack of audible masking frequencies might cause truncation distortion to become audible. But surely nobody would be cruel enough to domestic pets to make a track like that! Hmm, on second thoughts I wouldn't put it past Aphex Twin! laugh.gif

Regards,

DickD

This post has been edited by DickD: Jun 3 2003, 11:50
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Posts in this topic
- Jan S.   Test your soundcard for clipping   May 26 2003, 19:57
- - grbmusic   I'll try it and then I tell about it!...   May 26 2003, 20:03
- - grbmusic   It's a kind of joke??? With foobar is imposibl...   May 26 2003, 20:19
- - atici   I listened to it OK with all my DSP plugins off, i...   May 26 2003, 20:25
- - Jan S.   QUOTE (grbmusic @ May 26 2003 - 09:19 PM)It...   May 26 2003, 20:26
- - Jan S.   QUOTE (atici @ May 26 2003 - 09:25 PM)it soun...   May 26 2003, 20:28
- - grbmusic   QUOTE (Jan S. @ May 26 2003 - 04:26 PM)what y...   May 26 2003, 20:44
- - boojum   I am not sure about the distortion. I do get the ...   May 26 2003, 20:54
- - Pio2001   19.5 kHz ! At full power in headphones, I hea...   May 26 2003, 21:47
- - Thikasabrik   Well... it looks as if it isn't clipping for m...   May 26 2003, 22:44
- - ben   Yeah, I just clipped my ears with the 19.5khz tone...   May 26 2003, 23:08
- - outscape   QUOTE (Pio2001 @ May 26 2003 - 03:47 PM)19.5 ...   May 27 2003, 03:25
- - Rizban76   I suppose my sound card is really screwed up. I ca...   May 27 2003, 04:27
- - fewtch   MonkeysAudio is so annoying. No separate WinAMP p...   May 27 2003, 04:45
- - Mr. Mulder   If you give me an email address I cand send you ...   May 27 2003, 07:29
- - anza   When I have foobars resampler on and set to 48kHz ...   May 27 2003, 07:58
- - LPTB   QUOTE I tried with DirectSound and I got nearly sa...   May 27 2003, 08:08
- - KikeG   Ugh! I hear too annoying ultra-high pitched to...   May 27 2003, 08:13
- - Mac   Ugh, you should put a warning when you post sample...   May 27 2003, 08:30
- - freakngoat   That is the craziest sample ever. How does it work...   May 27 2003, 08:45
- - Halcyon   What a useful sample! My results for Audigy 2...   May 27 2003, 09:29
- - Garf   QUOTE (Halcyon @ May 27 2003 - 10:29 AM)Final...   May 27 2003, 10:23
- - tigre   Great work! I knew before that my onboard VIA ...   May 27 2003, 10:59
- - Rasi   the squirling reminds me of a bird singing.... gue...   May 27 2003, 11:01
- - Gabriel   On this computer I get a birdy sound, depending on...   May 27 2003, 11:25
- - fragtal   Does somebody have .flac version of this sample or...   May 27 2003, 12:42
- - tigre   udial.flac   May 27 2003, 12:49
- - fragtal   QUOTE (tigre @ May 27 2003 - 01:49 PM)udial.f...   May 27 2003, 12:52
- - Halcyon   Garf, Why is this sample theoretical? Can you ela...   May 27 2003, 13:15
- - tigre   QUOTE (Halcyon @ May 27 2003 - 04:15 AM)Why i...   May 27 2003, 14:10
- - LPTB   Ok I did a test at work, with SoundMax integrated ...   May 27 2003, 15:15
- - JEN   Wow, that gave me a headache I can hear clicki...   May 27 2003, 15:16
- - Jan S.   QUOTE (JEN @ May 27 2003 - 04:16 PM)Wow, that...   May 27 2003, 15:42
- - fragtal   I have to pull down the master-volume (of the Crat...   May 27 2003, 16:13
- - JEN   OK, I tried it with resampling and here are the r...   May 27 2003, 16:16
- - ViPER1313   Would anyone be willing to take the sweep.wav samp...   May 27 2003, 16:27
- - Sachankara   Ehh... What are you supposed to hear? It sounds li...   May 27 2003, 17:11
- - grbmusic   Jan S. you should advice that take the test with t...   May 27 2003, 17:20
- - sony666   QUOTE (grbmusic @ May 27 2003 - 05:20 PM)Jan ...   May 27 2003, 17:41
- - LPTB   @grbmusic bummer man, sorry for your speakers... ...   May 27 2003, 18:01
- - JeanLuc   Two chains in my system, both fed by a TerraTec EW...   May 27 2003, 18:25
- - tigre   QUOTE (Sachankara @ May 27 2003 - 08:11 AM)Eh...   May 27 2003, 18:49
- - outscape   QUOTE (grbmusic @ May 27 2003 - 11:20 AM)Jan ...   May 27 2003, 18:52
- - LPTB   @tigre About the sample you provided, I can hear q...   May 27 2003, 18:53
- - tigre   Which one?   May 27 2003, 19:07
- - LPTB   The mpc sample you provided named correct.mpc.   May 27 2003, 19:28
- - Pio2001   QUOTE (fragtal @ May 27 2003 - 06:13 PM)I hea...   May 27 2003, 19:45
- - tigre   QUOTE (LPTB @ May 27 2003 - 10:28 AM)The mpc ...   May 27 2003, 19:52
- - LPTB   QUOTE If it's less than in the .mpc file it co...   May 27 2003, 20:02
- - grbmusic   QUOTE (LPTB @ May 27 2003 - 02:01 PM)I tried ...   May 27 2003, 23:37
- - grbmusic   QUOTE (outscape @ May 27 2003 - 02:52 PM)did ...   May 27 2003, 23:40
- - LoKi128   Well, tested with Winamp and my shitty on-board so...   May 28 2003, 01:15
- - KikeG   I tested again at home with my Audiophile, and hea...   May 28 2003, 09:25
- - Pio2001   THIS is a killer sample QUOTE (KikeG @ Ma...   May 28 2003, 11:59
- - lucpes   M-Audio Delta 410 card... dial tone + very high pi...   May 28 2003, 12:38
- - 2Bdecided   In fact, there isn't a hard cut off limit in h...   May 28 2003, 12:42
- - Moitah   When using Winamp's DirectSound plugin (v2.2.6...   May 28 2003, 14:18
- - JeanLuc   QUOTE (grbmusic @ May 27 2003 - 10:37 PM)QUOT...   May 28 2003, 15:16
- - jues   Soundcard: Delta 410. Christ that hurt - yeah, pu...   May 28 2003, 15:37
- - DickD   I have a Win NT4.0 machine with a 'Pro16V-A Pn...   May 28 2003, 16:28
- - Pio2001   This is a picture of the aliases that can appear w...   May 28 2003, 18:33
- - fragtal   I just downloaded the correct.flac and I'm rea...   May 28 2003, 19:46
- - ViPER1313   Sounds fine to me on my SB-Live value w/ 48khz SSR...   May 28 2003, 20:24
- - atici   QUOTE (lucpes @ May 28 2003 - 06:38 AM)M-Audi...   May 28 2003, 20:39
- - Pio2001   QUOTE (ViPER1313 @ May 28 2003 - 10:24 PM)the...   May 28 2003, 20:50
- - kritip   QUOTE (Pio2001 @ May 28 2003 - 08:50 PM)QUOTE...   May 28 2003, 22:32
- - Stuv   Quite interesting sample this one. All ASIO, Wave ...   May 28 2003, 23:56
- - ViPER1313   QUOTE the sweep is more through and wont hurt your...   May 29 2003, 04:23
- - Halcyon   A quick note about Creative cards and audible arti...   May 29 2003, 09:09
- - KikeG   QUOTE (Pio2001 @ May 28 2003 - 08:50 PM)You s...   May 29 2003, 09:37
- - DickD   QUOTE (kritip @ May 28 2003 - 10:32 PM)I real...   May 29 2003, 13:27
- - mrosscook   I have an SB Live card and Harman-Kardon desktop s...   May 29 2003, 14:57
- - LPTB   KikeG, Halcyon You're both correct this is exa...   May 29 2003, 15:03
- - Pio2001   I remember people saying their SB live was incredi...   May 29 2003, 19:58
- - JonPike   Huh.. interesting. On XP here, can't rememb...   May 30 2003, 02:43
- - grbmusic   QUOTE (JeanLuc @ May 28 2003 - 11:16 AM)Sorry...   May 30 2003, 03:21
- - Halcyon   FYI. All of my test were done under WinXP Pro SP1,...   May 30 2003, 07:51
- - DickD   QUOTE (JonPike @ May 30 2003 - 02:43 AM)Hmmmm...   May 30 2003, 13:31
- - mrosscook   Pio, Since there may be issues with the OS for Cr...   May 30 2003, 14:08
- - lucpes   QUOTE (atici @ May 28 2003 - 07:39 PM)lucpes,...   May 30 2003, 14:18
- - Thikasabrik   Well, having tested more thoroughly at different s...   May 30 2003, 14:26
- - Pio2001   Below 44.1 kHz, if the resampling is done with ant...   May 30 2003, 19:01
- - Dave Hamaker   I extracted the sample to a wav file. I looked at...   May 31 2003, 00:30
- - Pio2001   The spectrum of the clipped sample has subharmonic...   May 31 2003, 01:37
- - Dave Hamaker   QUOTE (Pio2001 @ May 30 2003 - 04:37 PM)The s...   May 31 2003, 02:46
- - Pio2001   Here are the results of two bad processes performe...   May 31 2003, 09:29
- - Halcyon   QUOTE Switching to quality 2 (on a 1-4 scale) remo...   May 31 2003, 11:37
- - indybrett   Using Foobar through a Prodigy 7.1 soundcard. Jus...   May 31 2003, 19:29
- - Dave Hamaker   QUOTE (Pio2001 @ May 31 2003 - 12:29 AM)Here ...   May 31 2003, 21:50
- - JonPike   QUOTE (DickD @ May 30 2003 - 04:31 AM)QUOTE (...   Jun 1 2003, 01:48
- - JonPike   "foobar2000 player v0.666 released Changes: ...   Jun 1 2003, 01:57
- - Differenciam   Ack. My laptop made that sound quite painful.   Jun 1 2003, 02:30
- - Chun-Yu   QUOTE (indybrett @ May 31 2003 - 01:29 PM)Usi...   Jun 1 2003, 02:46
- - Halcyon   QUOTE (Chun-Yu @ Jun 1 2003 - 03:46 AM)Q...   Jun 1 2003, 10:09
- - DickD   QUOTE (JonPike @ Jun 1 2003 - 01:48 AM)OK......   Jun 2 2003, 14:36
- - JonPike   QUOTE (DickD @ Jun 2 2003 - 05:36 AM)The late...   Jun 3 2003, 02:42
- - DickD   This post has some factual assumptions that were i...   Jun 3 2003, 10:23
- - Garf   FB2K ditherer and noiseshaper should never cause c...   Jun 3 2003, 10:32
- - DickD   Thanks for the informative reply, Garf. I'll g...   Jun 3 2003, 11:34
- - Halcyon   I need help. I have tried everything that I can t...   Jun 3 2003, 13:53
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