When does Roon upsample and downsample?

Roon Software Discussion
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  1. Upsampling, Custom
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(2) expanding bit depth to 24/32 isn’t an enhancement–it would just fill the lower-order bits with zeroes and then increase the data rate going to the DAC unnecessarily. Expanding bit-depth when you apply DSP serves a real purpose–it ensures that information isn’t lost when the signal is attenuated.

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Thanks and what about the other suggestion ? Having a differentiated treatment based on what kind of signal is entering (for instance having all the following parameters activated : PCM 16/44 -> max up sample, PCM 24/96 Unchanged, DSP -> Unchanged)
Thanks

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@AndersVinberg beat me to that answer.

Choose “Custom”, then it will let you do select on a sample rate by sample rate basis:

Screen Shot 2017-02-07 at 6.15.41 PM.png699×644 39.3 KB

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Great ! Thanks

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Hi Brian, I have hundreds of ISO files and I see that there is no plan at this time for Roon to develop a program to play them. The software that I will be using can convert these files to 384 32 bit wav files. You wrote that all DSD files are converted (downsampled) to PCM. So aren’t I better off converting them to PCM initially so there is one less conversion by the Roon software lessening any potential strain on the CPU? Alternatively I can convert them to DSF files which would be quicker but then they would be converted. My LaScala DAC which I will be upgrading, will be able to play 384, DSD 64 and DSD 128 files.

By the way, I just converted a few of the files to test the program, then imported the files into Roon. To my amazement Roon downloaded the cover art automatically which will same me a lot of time doing it. (Most of files are from ripped CDs which already had the cover art with the file.)

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Keep them as DSF, Roon will transcode them as needed depending on your DAC’s capabilities. There’s no harm the server doing CPU intensive stuff, unless it’s feeding your DAC directly, in which case you’re better off adding a raspberry pi or other low power system on chip to run Roon Bridge.

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If you plan to have a DSD-capable DAC, then best to convert the ISOs to DSF. As mentioned before, it’s much quicker. They should also sound better, if your DAC is capable of playing them directly, as Roon can send them to the DAC unchanged.

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You wrote that all DSD files are converted (downsampled) to PCM

I’m not sure where you’re getting this impression, but it’s not true in general. There are many situations where we do convert to PCM, but it far from all.

Keep them as DSF. It’s a lossless conversion. There’s no harm in doing the conversion on the fly–in fact that’s better because over time algorithms improve. Batch converting large numbers of files is painful, prevents you from seeing any improvements later, and most CPUs can handle whatever is necessary on the fly.

But more to the point, it sounds like you have a DSD-capable DAC, so for that one, you’ll very likely want to play the files directly as DSD.

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Thank you, I quoted you from your post above 28 days ago. Anyway I will convert them to DSF.

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The key word in that sentence was processes, since that conversation was about digital signal processing. But it doesn’t apply to all situations–only those where DSP is being used.

We certainly do distribute and play DSD without processing it–in those cases it’s bit perfect.