DSD512 - Is this even possible? [yes, just needs more cpu]

I run Roon Server on a 8 core/16 thread Xeon machine. The clock is 2.6Ghz. It has 16GB of RAM.

I have never successfully upsampled to DSD512, although I have a couple DACs capable of that res. I am thinking that clock speed, rather than number of cores, is the limiting factor. Is this true? I upsample to DSD256 without any problems.

Is DSD512 more than just theoretically possible? Is so, some recommendations on capable machines, please.


What do you try to achieve?
Upsampling can not magically add information not in the original file and such an excessive upsampling result in most cases in a decrease of sound quality due to overstressing you network or your hardware.
More is not automatically better when the more is achieved by pumping in only air and not real substance.

How about custom reconstruction filters and DSD modulators implemented in computer software that sound better than the DAC’s internal implementation?

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I’m upsampling to DSD512 with a basic i7 sonic transporter w 8GB RAM (the Sonic Transporter i7 is an i7 7700). The i7 is fan-less so I’m assuming it’s a low power unit (massive heat sink though(.

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I think you need a very short (few taps) convolution filter to be able to do DSD512, I can’t even run DSD256 with my DSP and Im on a modern fast computer.

What signal path do you have? Are you using any other filters? If so, try to turn them off… especially convolution.

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No filters.

TIDAL->Bit Depth Conversion->Headroom Adjustment->Sample Rate Conversion->Sigma Delta Modulator->RPi/DietPi->iFi iDSD

Does Roon use all cores available to it or is this not even an issue in upsampling? Clock speed is probably the deciding factor, yes?

what processing speed do you get for DSD64/128/256/512?

Miska of HQP does say processor speed is important, your processor seems it would be capable tho. Could the Rpi be the issue? is it capable of passing 512 thru it? Try removing it and go direct from PC to dac and see. Also did you enable Roon to utilize all cores (forgot what it is called) in DSP settings that could be it to. I run a i7-6700K at 4 Ghz and have no issues up sampling to 512 with roon alone or in conjunction with HQP.

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DSD64-4.3 DSD128-3.1 DSD256-1.6 DSD512-0.8

There’s nothing else running on machine when I took these measurements.

Thanks for your reply.

The upsampling takes place on the server machine, so as far as capability RPi has yet to enter the picture.

The only place in Roon, that I can find, where it references number of cores is related to background analysis of music files, vis a vis metadata, and that only goes up to 4 cores. However, I don’t believe that setting is relevant in this case.

Yeah, that’s kind of a hassle, but I guess I’ll tinker with that.


Roon uses 1 core per zone normally, or 2 if you enable “parallelize sigma delta modulator” setting and are doing DSD output. If you haven’t turned this on yet, try that first:

20 PM

In general, the “many slow cores” model like your XEON is not the best for Roon. Almost none of our users have this class of hardware, so putting in a ton of effort/complexity optimizing for horizontal scalability doesn’t make a lot of sense. This isn’t just about audio, either–for UI responsiveness it’s also advantageous to have faster cores rather than more cores.

DSD512 upsampling is stable for me on a NUC5i5–I’ve been running my headphones zone like this since before we released DSP features, and processing speed is pretty healthy:

Occasionally I will hose the system and get a dropout here or there if I try to do too much other stuff at the same time (too many zones, importing big batches of content, multithreaded analysis, etc). If I was designing a core specifically around this use case, I’d go a little bigger on the CPU than that.

On my bigger machines (i7-6920HQ, i7-7700k) DSD512 is very solid even with other loads going on at the same time.

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Yeah, I turned that on a long time ago and it did make a difference for all below DSD512.

Accepted. I’m not surprised. The only reason I have the machine is I bought it used for $160 and I wanted to try running some stuff in VMs, FreeNAS, PFSense, Roon, a Hacintosh, a couple WIN10s etc.

It’s been awhile since I had Roon Server on my i5 Mini, but it seems like I couldn’t run DSD512 there either.

Anyway, thanks for response. I guess when money allows I should get an i7. I’d definitely need it for HQPLayer, anyway.


@danny - Thanks for your help.

Your VM setup might also be having an impact…just another thought. It might run better on bare metal, or you might be able to allocate more resources.

NO VMs now. Straight WIN10.:sunglasses:

Why only 2? Most fast processors today have 4.

So a Ryzen with 8 cores and 16 threads is total overkill since at most roon spreads the load over 2 cores? Those cores benefit HQP.

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Your skepticism is warranted.

For DSD, why even DSD256, let alone DSD512? Only DSD64 faces some debatable noise shaping and low pass filtering issues just above the audio band. By DSD128, those concerns have been rendered irrelevant.

High end D/A conversion long since has veered into the realm of “if possible, then necessary.”


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Hey Slim, is your background audio analysis still going? And at full throttle?

My old fanless sonicTransporter i7 doesn’t break a sweat with DSD512 so I can highly recommend that. I’ve since given it to my old man (my dad) since I’m only using one zone now and I’ve setup multi zone for him and it does DSD512 and other stuff quite easily in his setup.

Can you tell me, what is the benefit of DSD512?