Fixed sample rate output for sub integration

I’m trying to integrate my mains and subs using a dsp crossover (minidsp). I’m using the internal dac on the dsp to run the subs and the crossed over digital output to drive an external dac. The issue is latency correction for the 2 different DACs.

I believe that latency (time through the DAC) is different for different sample frequencies. Since the dsp processes everything at 96kHz anyway (although input equals output f) I figured that I would use Roon to fix the sampling rate to 96KHz hence removing the different latency issue.

My question is, how do I set this up and how much CPU does the resampling require? I’m running this all on a NUC but I was hoping to move it all back to my NAS (Synology).

Anyone done this?

Hi, @Ralf_Ortmanns.

My experience with using a DSP filter to adjust sample frequency is that it doesn’t use much CPU. I’ve done it on a ROCK (NUC) and on a Synology though both of those units are fairly high end.

I don’t think anyone will be able to tell you anything more specific about how much CPU it will use because, percentage-wise, this will be highly dependent on your hardware. My guess is that if it you were previously able to run your core on your Synology without running into any issues, you probably have enough CPU headroom for resampling. Best way to figure it out is to just test it. It’s very easy to keep two cores running and just move your authorization between them while you’re testing.

You can set up the frequency conversion on a Mac, a PC, or an iPad (though not a Mini). Because you want to move everything to 96kHz, you can’t just use the simple “Max sample rate (PCM)” setting in each device’s setup. You actually have to set up a DSP filter.

So in Roon, select the zone you want to modify as if you were going to play music to that zone. Click the volume icon to the right of the zone icon. In the little window that pops up, click “DSP”.

In the left nav, you’ll see “Sample rate conversion”. In the top setting, which is called “Sample rate conversion”, select “Custom”.

You can now set the target converted frequency for all source frequencies. You’ll just need to set everything to 96kHz. Tweak anything else you want, and you should be good to go.

Good luck! :slight_smile:

Thank you for that. As far as CPU goes I was just making sure it doesn’t require an i7 or something. I’m running a Synology DS1821+, I previously ran Roon in the other Synology which is now my backup. It runs an AMD Ryzen V1500B. I believe it’s supposed to be quite good.

I’ll do as you suggest and install and give it a try.

Thanks again.

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