Recommended USB interfaces for Active DSP crossover


I’m considering using Roon for an active crossover setup, in which Roon would set the crossovers in software.

I am considering the Okto Dac 8, various motu and Focusrite units.

It would be great to understand which units have been successful for fellow roon DIYers.

Best regards

I use a Motu 8A, with Roon running on windows. It works great with one caveat: if the sample rate of the source material doesn’t match the sample rate of the last track played, Roon loses control of the Dac. You have to push play a second time (which makes Motu change its sample rate to that of the new source material).

For simplicity, I’ve fixed the sample rate of the Motu to 96kHz and upsample or downsample all sources to 96kHz in Roon. One added benefit of Motu is that it’s a studio mixer. I’ve also hooked up my home theatre and another couple of analogue sources as inputs. I don’t have to worry about switching sources.The Dac will just play whatever source is coming in (or two or three sources at the same time if that’s what you want).

My crossover DSP is calculated through Audiolense for optimal time alignment of all drivers.

Just a warning Motu doesn’t seem to work if Roon runs on Linux (no driver).


I’m using Focusrite 18i20 Gen3 with Audiolense.

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Really helpful information.
I wonder if there are any Okto Dac8 users here?
Seems like a great units, that measures very well.

How much CPU use are you getting with your multi way setup, up sampling to 96k?
How many channels are you processing?
How do you find the sound quality?
Is the Motu8 quiet? do you get any hiss from the unit? (That’s not amp related).

Any feedback on the combo?

Is it silent? Any noise/hiss?
Sampling issues?
Are you using with windows, Mac or Linux?

I have Roon running on a Nuc (not super powerful: Intel Core i3-7100U). Sample rate conversion to 96kHz, 3 way speakers (6 paths 131k taps). The processor show 8x, so not too taxing.
The motu is dead quiet with my ear to the speaker (91dB (2.83 Volts @ 1 m) sensitivity). Mind you the amp gain is set at only 17.0 dB.

No sampling issues once set at 96kHz.
The sound quality is perfect (THD below audible).
I’m using Windows.
As I said Linux is a no go with Motu.

No experience with okto but the reviews are great.

Ok amazing.

My amps have circa 14db. So noise should be low. But I will be using 97rb sensitive drivers. Compression top end and miss.

Thanks for that info.

The DAC? No noise and hissing coming from the DAC… if anyone is having any noise or hiss from a DAC there’s a problem. Ground loop noise is a different thing though, that’s an overall system thing. But not issues at my end fortunately.

Hiss from active speakers is also a thing for some models. Maybe amp.

No sampling issues. I use Linux and macOS trouble free.

That’s great info thanks.

Did you install drivers for Linux?

No drivers Focusrite to install for Linux. It’s not officially supported.

I use HQPlayer OS (Linux).

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Thanks for this info.
I’m not interested in HQ Player at this stage.
I suspect I will need to put a Win10 PC back in my listening room.
Just need a silent solution.

I have been happy with my RPI4 via USB to my RME ADI2.
My core currently sits on a HP elitedesk i7 9700, which is super snappy.

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Hello @Omid_Mostachfi ,

Thanks for your insights. I am considering the Motu Ultralite MK5 or the 8a and your comments are very helpful.

  1. I want to use Acourate or Audiolense (I need to yet decide) filters with digital crossovers for a 2.2 system. I see you use Audiolense. Did you consider also Acourate and if yes, why did you distill towards Audiolense?

  2. Similar question, any benefit from the 8a compared to the mk5 for my purpose?

  3. Regarding extra inputs: you mentioned that you have hooked your home theater. Can you have a separate digital input (besides the computer where you do the routing), or does it have to analogue?

  4. And finally, about Roon losing control when you change sample rate, is this still an issue or has it been resolved?

Many thanks!

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1.I only tried the trial version of Acourate, it wasn’t super user friendly. Mitch Barnett seemed to have started with Acourate and moved on to Audiolense. So I just settled on Audiolense. It’s good but does have its quirks.

  1. I haven’t tried the Mrk 5 but it seems like a good option (newer than 8A but If memory serves it has a newer software that did not seem as flexible as 8a’s software). I like that it has a Mic input which the 8a does not have. Make sure the number of I/O suits your needs.

  2. My HT is an analog input. But you could have a digital input. you’d have to use an optical cable and route that through.

  3. The issue persists. I just convert my digital inputs to 96kHz, and leave the motu fixed at that rate. Otherwise you have to hit play twice for Motu to adjust to the new sample rate which is annoying.


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I have the Motu Mk5 lite, and use Roon.
My Motu changes sampling rate automatically no issues.
Sampling rate changes take a few seconds.

I have my Motu mk5 connected to a RPI4 ubuntu endpoint Ver 21.10.

With windows and the Asio driver it should be perfect also.

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Thanks a lot, this is useful information.

Thanks, this is good to know and gives the MK5 an advantage

Wasn’t there an issue with lack of drivers for Motu on Linux (or was it just under Rock), or is there a driver that works for Mk 5?

If you search this forum I created a few threads on the Motu.
The Motu Mk5 lite is an audio class compliant device.
In theory it should operate without drivers.

I have done extensive testing using multi channel audio for an active 4 way setup, and the Motu works perfectly under Linux Ubuntu 21.10, which uses Kernel 5.14.

Its all about the Linux Kernel. Roon rock runs a customised and very old Linux kernel, (Amended) which doesn’t work so well with the Mk5… I use a RPI4, so I don’t have the Nuc in my listening space.

I have had no issues using Ubuntu Kernel 5.14+, completely without any drivers.

I will say Roon produces noise on channels 9-10, as it only addresses a maximum of 8 channels on USB. Something to note if you need 9 or 10 channels. In my application I simply mute these channels down, within the Motu software.

These thread links might be helpful.
My experience with the Motu Mk5.

Noise on channel 9-10, using Roon multichannel assignment.


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I highly recommend the Motu Mk5.

I will note the Motu Mk5 takes a few seconds to change sampling rates automatically, so I miss the first few seconds of a song (if a sampling rate change is required), say 5 or so. You can easily fix the rate if this bothers you… I mostly listen to Redbook 16b, 24b, and 96k so sampling rates are fairly consistent, but moving from an RME ADI2 dac fs (which boasted instant switching), the sampling rate change time is noticeable.

I personally partner my Motu and RPI4 with a quality linear power supply.
Measurements would probably show no difference, but it made a worthwhile improvement to the combo’s sound quality IMO. I’m not interested in debating the validity of using LPS, but I would recommend a quality supply either way.

This is what I use:

I had the unit modified with a larger choke to provide lower heat output at higher amp draw on the 5vdc for the RPI4.

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