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Post by Drewmo on Dec 3, 2004 4:27:17 GMT
Hi Michael
Been having great results on Magix Studio with the ASIO4ALL. These drivers really heklp guys like me that are using the Audigy card, but I recently discovered an overload issue that is similar to what you mention on your web page when recording Audio. When I record a pure tone, as soon as it reaches the max value, instead of clipping, the samples switch rapidly between min and max values. Gives a horrible distortion sound! The Direct Sound drivers don't cause the same problem - they just show the waveform clipping. I'd insert a BMP of the waveform into this message but I don't know how to do that!
I tried version 2.1 but still doesn't fix the problem, regardless of buffer settings, etc. I'm using an Audigy 2 with a 2.4GHz P4, VIA chipset, NVidea drivers, WIN2k, 512M RAM. In all other aspects, the drivers seem to be working great. Any suggestions?
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Lindsay Briggs Australia
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Post by Lindsay Briggs Australia on Dec 4, 2004 6:49:22 GMT
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Post by Michael Tippach on Dec 6, 2004 1:24:14 GMT
Got your BMP in PM. This clearly shows digital distortion. Do you have the resampler enabled (i.e. running at 44.1 and "Always resample..." enabled?
If not, then ASIO4ALL does not do any actual processing on the audio data and passes on the reformatted frames (which does not alter individual sample data)
The resampler _does_ saturate. But, of course, this would only apply to the minimal amount of overdrive that can happen when the resampler is being run close to 0db, not to any already digitally clipped input data. If it turns out the resampler is generating the digital distortion, this would be a bug, otherwise there is very little we can do.
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Could be Resampling
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Post by Could be Resampling on Dec 7, 2004 3:26:13 GMT
Just to clarify, this problem occurs when recording in Magix Midi Studio, when the line inputs to the soundcard are overdriven. The waveform I sent was with a sine waveform source deliberately overdriving the input of the soundcard. If I record the WAV in, say, the Windows system recorder, it just gives a flat clipped waveform as you would expect. But the bizarre rail to rail oscillation in the BMP I sent is what is you get in the Magix program.
I'm guessing the problem is in the reseampling: the Magix Midi Studio program is very popular among music makers, and the Creative Audigy card is a very affordable sound card, but apparently, Midi Studio samples at 44.1kHz, and the Creative hardware is locked at 48kHz. There is thus no way not to use resampling.
Hence there is a body of people over on the Magix forum who are really interested in the ASIO4ALL drivers because they are wonderful for low latency etc with the Creative cards (one of the most popular soundcards).
Any other diagnostic testing I can try running?
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Post by Drew Mo on Dec 7, 2004 3:28:31 GMT
That last message ::)was from me, but it wouldn't let me enter my name! ;D
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Post by Michael Tippach on Dec 7, 2004 21:07:25 GMT
The most likely reason why you do not see this digital distortion with DirectSound is that DS/MME record with 16 bits only, the equivalent of "Force WDM Driver To 16 Bit" in the ASIO4ALL control panel.
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Post by Drewmo on Dec 8, 2004 2:59:51 GMT
As per the email I sent, yep, the Force to 16 bits does the trick and fixes the digital distortion. So I guess I never had the full 24bits that Audigy claims then, so I won't miss anything if I use that setting!
Thanks for the help. I'll post a note on the Magix forum so that other people can take note of this.
May be a stupid question, but is it possible that the ASIO drivers could support higher resolution in the future for this type of soundcard?
Thanks again...
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Post by Michael Tippach on Dec 8, 2004 23:50:16 GMT
May be a stupid question, but is it possible that the ASIO drivers could support higher resolution in the future for this type of soundcard? As far as your sreenshots, it looks like it _does_ support 24 bit, just not when you drive your inputs into overload - in which case the "analog" distortion from clipping is replaced by digital distortion from binary wrap around. For a decent recording you want neither. If distortion is desired, there are better sounding VST effects than the input stage of your sound card  BTW, if only the positive peaks show digital clipping, it could well be that the signal has a digital DC offset of just one bit. Positive max. is 0x7FFFFF, negative max is 0x800000 = 0x7FFFFF + 1! This could even be caused by applying dither somewhere in the recording path. |
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Post by Drewmo on Dec 10, 2004 4:49:40 GMT
Hi Michael, thanks, understand - I don't normally overdrive the card inputs intentionally ... I originally encountered the problem by accidentally slight overdrive on some vocal work, and instead of one or two mild clips, I ended up with a horrible crackle sound on 'ss'es and 'ppp's, which fortunately I was able to manually edit out. Based on that experience, I think I'd rather stay in 16bit mode just in case, rather than rely upon the signal never exceeding the input limits under any circumstances. BTW, so far, no further problem found using the 2.2 version, and checking both boxes to force 16bit and 44kHz - in fact two definite thumbs up!!! You have my email address, let me know if you need an extra volunteer for any beta testing! |
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