INTERACT FORUM
More => Old Versions => JRiver Media Center 19 for Windows => Topic started by: Blaine78 on September 27, 2013, 07:05:09 pm
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Listening to a PCM track with predominately low bass hitting a full 0dB peak, I hear clipping distortion with JRiver's PCM to DSD conversion enabled. The distortion is not present during direct PCM playback, so I thought i'd look into this a little more.
I generated a a PCM 16bit/44.1khz file of pure 100hz sine wave at full 0dB, this makes it easy to hear distortion if present. Sure enough, the track clips when PCM to DSD is engaged. Reducing the volume on JRiver by -2dB completely eliminates this clipping. I played back the same file as direct PCM, and no clipping occurs.
I have a Mytek DSD DAC. I tested the analogue output stage to see if it's the culprit here, I tested this by turning down Mytek's analogue volume, the distortion still remained. Turning down the digital volume on JRiver or Mytek (Mytek has both digital and analog to chose from) by -2dB, distortion is completely gone.
I have DSPs turned off, and run JRiver with ASIO DSD bitstreaming.
I hope you can help.
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What if you use Convert Format in MC to make a DSF, then use Convert Format on the DSF to make a WAV? Will the final WAV have the clipping you're seeing or not?
If it doesn't, it would point to the problem being in the Mytek. If it does, the problem is somewhere in our chain.
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This has been brought up before (http://yabb.jriver.com/interact/index.php?topic=82074.msg572044#msg572044) - I suspect it's because DSD is not supposed to hit 0 dBFS, and I wonder if some DACs are adding +6dB with a DSD input, which could cause them to clip.
The Mytek DAC may have some overhead, but not the full 6dB.
I wonder if DSD encoding should have -6dB applied.
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No clipping when converting to DSF then back to Wav, except final wav now peaks at -4dB.
Hmmm. It would appear also a Mytek problem if turning down the digital volume on the Mytek gets rid of clipping, if was a JRiver issue, the distortion would still be present.
Thanks for your help guys. I'll contact Mytek
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This has been brought up before (http://yabb.jriver.com/interact/index.php?topic=82074.msg572044#msg572044) - I suspect it's because DSD is not supposed to hit 0 dBFS, and I wonder if some DACs are adding +6dB with a DSD input, which could cause them to clip.
The Mytek DAC may have some overhead, but not the full 6dB.
I wonder if DSD encoding should have -6dB applied.
Do your average SACDs have this kind of dB peak as standard too? meaning would also create clipping in Mytek, or is JRiver applying a hotter than standard, but within DSD specs? i'm just not 100% sure what the max dB is for DSD. PCM, 0dBfs is max.
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I don't think there's a universally accepted answer here:
http://yabb.jriver.com/interact/index.php?topic=81265.0
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I don't think there's a universally accepted answer here:
http://yabb.jriver.com/interact/index.php?topic=81265.0
It's interesting to go back to this now that we have True Peak measurement - 70% of the DSD files I have analyzed so far have less than 6dB headroom. (turns out I had not included SACD in my "not analyzed" playlist)
If I include files up to -7.0 dBTP (because you have potential variance) that increases to 84%.
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So it seems playing normal SACD wont be a problem, and the likelihood of reaching -2dB is even more rare, but with pcm to dsd conversion, hitting 0dB will be very common. Maybe the 6dB increase is a little too much for this conversion process and suggesting just a 4dB increase will solve the clipping/distortion for some DSD DACs?