S40 as HQPlayer machine

Hi all!

I’m actually using a S30 as Roon Rock server and I’m really satisfied.

Now my plan is to use a (additional) S40 as HQPlayer machine. But I’m not sure about the HQPlayer performance of the S40. Actual I’m using a MacMini M1 core as HQPlayer machine. I’m always up-/resampling to DSD256, only PCM input (44.1, 96.0 and multiples) from NAA backend. My filter settings are:

1x poly-sinc-mqa/mp3-mp
Nx poly-sinc-mqa/mp3-mp

This works stable on my MacMini. I would prefer poly-sinc-gauss-hires-mp for 1x and Nx with ASDM7ECv2, but this setting produces hickups sometimes.

My question is: are there any experiences with the S40 performance of HQPlayer? Do you think my settings are possible on a S40? Which are the most CPU consumption filters/settings you are using without hickups on a S40?

Thanks a lot for some hints!


I had an S40 and it struggled to deal with the more intensive processing requirements either converting to DSD or any of the heavy noise shaping filters. I don’t recall exactly the limit point, but I don’t think any of the EC modulators worked and as mentioned for the heavy filters the delay could be as long as 30s or not work at all.

If you are hoping that having the S40 will allow you to use all the HQP filter options, then I’m afraid you’ll be disappointed.

Thanks for the input!

I have the possibility to test the S40 before buying and will do.

Any other options? The K50? But this device is really pricey. :frowning:


I upgraded from the S40 to the K30 and if that’s in your budget, I’d definitely recommend it.

The K41 has the K50’s Server engine. I can’t say whether or not that will be powerful enough for you though.

I forgot to say: I need an USB audio output to connect my DAC… So I think K30 and K40 will not work.

K30 has a USB output, in fact that’s all it has…

I was thinking that you’d use it with your S30. S30 as Player + K40 as Server. That will be a step up from a K30 if the S30 is powered by the S60.

K30 also has ethernet direct stream.

Ah yes, thanks for correcting…

Were you using the S40 in server only mode or as server and player? I am looking at the S40 server only duties and disappointed to see you comments about not be powerful enough to handle some DSP. I had thought as server only the S40 would have plenty to grunt. Mind you I only upsampling in Roon to max PCM - DAC can upsample to DSD 512.

I was using the S40 as both server and player, so that may have affected what the unit could process. Since changing to the K30, the ability to handle heavier load combinations definitely improved and some of the ones that didn’t work on the S40 alone, run perfectly well on separate units.

I haven’t really explored the limit as I’m mostly using Squeeze at the moment.

First off, PCM upsampling is not CPU-intensive. You will have no problem using the S40 to do this. When running Roon, I use HQPlayer integration to scale to 768K. My K30, which features the same server board as the S40, barely breaks a sweat.

DSD upsampling is another story. HQPlayer features some filters that require a very powerful CPU. The server board in the K50 is better suited to this, but I think ultimately one might need to look to a custom build for this. The CPU is generating so much heat that a server with active cooling will be required.

Happy your experience was much better than mine, but with my S40 it wouldn’t run the heavy filters with max upsampling…

Which are the “heavy filters”?

If I recall correctly, it was the Sinc M/SInc L range of filters. When running these the audio was interrupted for a second or two every 20 seconds or so. I haven’t compared this using my K30 as I’m not currently running HQP. Perhaps it wasn’t related to processing power but I’d made that assumption after reading posts on the Roon forum. Whatever caused it I never found a solution and have since upgraded (although not because of this).

On another note, have you any experience running HQP without Roon? I’m curious as to what that consists of I.e. what would one run on the server?


These are what I use and they don’t consume much CPU. This was confirmed back when AMS displayed a CPU utilization chart. If you had interruptions it was very unlikely that the hardware was the problem.

This is how I have configured it.

Yes, I ran HQPlayer stand-alone n the early days of having my K30. HQPDcontrol v4 is one of the apps I used to control playback. You need to first have HQP scan folders in your library. If you have a large library this can take a while so I recommend you choose a smaller folder the first time. In my case below, I scan a folder that has only 360 albums. Once I see the list here, I scan with HQPDcontrol v4.

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That would have been useful, hopefully it’s on its way back.

Yes it is. It will be nice to have that again.

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