INTERACT FORUM
More => Old Versions => JRiver Media Center 28 for Windows => Topic started by: qiking on January 14, 2022, 03:14:14 pm
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Why is it that in the audio path when playing a dsd compressed wavpack file that shows as DSD64 (1x) in the sample rate column there is no low pass filter when not bitstreaming but when playing the dsf file it shows low pass filter? Am I risking damage to my speakers playing dsd to pcm .wv real time conversion?
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That's only an option in the DSD plugin currently, so WavPack does not have it.
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If the output from wavepack is PCM and not DSD, then you should be able to add a low pass filter in DSP Studio to cut out the high frequency noise.
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It’s not exactly true that there’s no lowpass filter in the realtime DSD to PCM conversion built into WavPack; lowpass is required to avoid aliasing the DSD dither noise into the audible band during decimation. However, the lowpass used is a rather mild 56-tap FIR that’s down 100 dB at 235 kHz. This eliminates the vast majority of the DSD dither, and is fine for an 8x decimation, but still leaves some peaking at about 90 kHz (which is where the upsloping dither meets the downsloping filter):
(https://www.wavpack.com/dsd2pcm.png)
That’s not high enough to damage tweeters unless you played very low level audio with the gain cranked way up (a lot of electronic music has more energy than that above 10 kHz). But there’s no good reason to send that to a DAC either (the smoothness of the spectrum shows that there’s no information there...it’s pure noise).
If there’s no other lowpass filter available with a more reasonable cutoff (say 30 – 40 kHz), then I would recommend downsampling to 88.2 kHz (I assume that’s available). That will preserve the audio and remove virtually all of the remaining noise:
(https://www.wavpack.com/Downsampled-88.png)
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My question is the dsf wavpack compressed file is a dsd file the same as a dsf or dff only that it is compressed similar to flac is to wav. So JRiver sees the file as a dsd file not pcm but the dsd plug in doesn't recognize it as such. That is puzzling. The files show dsd64(x1). The file is only compressed not transcoded.