Low Level Crackling - Clock issues?

I don’t see how all the XL functions could work, with multi channel?!

As previously mentioned, OP in this thread is only interested in stereo working.

One of the posts you quoted above is about HDMI and multichannel with RoPieee, not related to this particular thread issue

We shouldn’t confuse too many different things in this thread and stick to his issue

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Sure. Within that thread, questions were asked about USB audio (Albeit Multi ch).
Its all related, stereo or otherwise. Linux compatibility simply comes back to the kernel compatibility and the device supporting USB compliance.

They all say “Class Compliant”

Even Focusrite say that on their FAQ page about Linux

The practical reality is mostly not straightforward

Maybe changing though. Motu seems to have made an effort.

RME walk the walk

We agree.
The most recent kernels (5.11+) seem to solve this issue, or at the very least improve the chances of success. Like I said, the solution is Kernel + USB compliance.

UPDATED… Sorry I have updated a few times, as I observe issues.

OK, So I took the time to install Ubuntu Server 21.04 on a Series 4 i5 laptop.
uname -r = 5.11.0-36-generic
I then installed Roon Server.

All observations are with the Motu Mk5 lite connected to the Roon server via USB:
(Please bear in mind with the Motu directly connected to my RPI4, everything works perfectly)

Test 1: Stereo
When I set the device as 2.0, and downmix, Stereo works, but I get noise on unused channels.
I did experience crackle using my PC’s USB 3 port. Using a USB 2 port everything is fine (Cable?)
Easy enough to mute unused channels down in Cue Mix.

Next I set the Motu as a 7.1 device, channel mapping, procedural mix.
Stereo works, and it seems I get no noise on unused channels, no crackles etc using USB 2.0 port.
USB 3.0 port I have low level crackle (Could be the laptop or cable).

Test 2: Multi channel
I set a procedural mix, set the device to 7.1, channel mapping.
I get 8 channels of audio, and random noise appearing on channels 9-10 as observed on other threads. USB 3.0 I get low level crackles, similar to an old vinyl record.
USB 2.0 port is fine. I wonder if I need a more recent PC, or a new USB cable.
I’m using the OEM Motu one…

This is very odd, as the RPI4 running Ubuntu is perfect, on USB 3, or 2 ports.

I hope this helps everyone.

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It does not work. I tried to add something in rooExtend to give Roon the information that there are more than four channels. But my approach failed. I could not make it run without occasional dropouts.
I Sold the Motu M4 and got a RME ADI-2 Pro FS R. It also has a four channel DAC but on the USB side it hast either six or eight channels. I use it with Roon on a Pi4 with rooExtend and the built in Roon Bridge. I run a 2x2 System with it with the crossovers in Roon convolution filters.

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Perfect, thanks.
I run a Motu MK5 lite, with RPI4/Ubuntu USB, works perfectly to.
Thread is here: Motu UltraLite-mk5

It seems there are certain combinations of setups which Roon just doesn’t like.
I.e. Motu direct to Ubuntu/Roon Server, V’s using a RPI4/Ubuntu endpoint.

In saying this, Win10 works in every combination, with my MOTU running its Asio driver.

Running the Motu at a RAspberry Pi4 you have to use a REAL USB3 cable. The cable shipped with the Motu will not work. USB3 cables have more wires inside. Use this at a USB3 Port of the Pi4 and the interface can be used.

Mine has worked perfectly thus far. No issue into the RPI4/Ubuntu.
But I will grab a different USB cable to try, and better test the USB 3.0 ports on my PC.

Motu supply a USB C to Type A cable.
I would assume this cable would be USB 3.1 compliant.

Excuse my dumb questioning, but you did install Roon Bridge in DietPi software, right?
If so, what did you see, exactly?
no go is a little bit too monosyllabic, although counting two syllables :zipper_mouth_face:

Just trying to understand…

BTW, current DietPi 7.6 kernel version is 5.10.60-v8+ on my RPi3b+

No go refers to the complexity of getting it all up and running on my Pi4b - flashed and inserted the card, but unable to access the Pi subsequently, even though I can see it’s IP address.

I’m an audio engineer but not a software expert and complexity of getting DietPi working is not for me, especially compared to RoPieee, Volumio or VitOS.:slight_smile: :relaxed:

My Pi’s are all run headless - they’re nowhere used to their full potential, I realise that. However I’d prefer to spend time listening to music than fiddling around with software installs - I do enough engineering when at work!!

So I didn’t have time to spend with DietPi last night, but this is not to say it couldn’t work or is deficient in some way, other than not being as plug and play as other offerings.

Sorry for any confusion arising from my initial vagueness and wow! - the number of overnight replies to the thread is amazing: thanks all!! :smile:

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I hear you, no worries!
Had just been curious as to where you got stuck in a dead end…
Good luck then!

Out of courtesy and curiosity, I just got round to installing DietPi and then Roon Bridge, via the software search, then install option on the DietPi ‘desktop’.

Still crackling apparent.

Currently trying to install ubuntu on my Pi4 B, but I can’t for the life of me work out how to get the bridge installed afterward.

Right, after much faffing and flashing and ssh’ing, finally got Roon Bridge running on Ubuntu 20.04.3 LTS and the crackle is still there.

Not as bad, it’s almost listenable to now, only kicking in on transients in the music. Played around with the device settings and dropping master clock to low priority helps, as does adding in a bit of buffer.

However, I’ve got the RME as a fallback until I go through it all over again when the M4 arrives, next week.

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Good on you for testing but alas it is the well known problem of Focusrite and Linux rearing it’s ugly

I have the 18i20 Gen3 and tried everything already lol

Looking forward to your M4 experience update

Keep Ubuntu locked and loaded for that test :slight_smile:

Now he says it’s already been tried on the 18i20 G3!!

Yes, the Ubuntu/RooBridge is on a spare RP4, so it’s all ready for the M4 arrival. Shame that the 18i20 can’t work (yet) as it’s got twin headphone outs, which would suit my wife and I for listening sessions when our little boy is asleep.

True, the RME ADI-2 DAC has phones and IEM outs, but balancing their levels is virtually impossible without the independent gain knobs of the Scarlett. May have to look into a Fireface UFX + instead.

Lol I said I have it and tried to (strongly) hint early on this is a well known Focusrite problem

I linked 2 threads and could have linked 10 more :grinning:

And therein lies my eternal desire to make things work, by blocking out the negative!

You did hint and you did link, but I misread, possibly deliberately, that Ubuntu/RooBridge was a solution for Focusrite, whereas it seems to be a solution for MotU only, among the ‘pro’ audio interface manufacturers.

My bad and my evening partially wasted. However, got to listen to some old Nils Frahm favs again, so not a total waste.

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All good.

In those threads I linked are the 2 guys that have worked out the potential fix.

They are working on bringing the fix to the mainline kernel one day.

So the day there is a fix you will hear about it from the guys doing the fix in those threads I linked… You won’t hear about it from anyone here in this Roon thread. That was the point of me linkin those

It will take a while because they are busy pro audio guys like you and doing the Linux fix in their spare time

It needs fixing. So it wasn’t me being negative. No amount of positive vibes will help :grinning:

Correct those other guys that helped in this thread don’t have a Focusrite

Hopefully your M4 works out the gate

As I mentioned , someone has made an effort to make Motus play nice with Linux with latest kernels. Could be Motu themselves or a smart user has done the work

Motu and RME are the exceptions , not the rule, when it comes to Linux with pro interfaces, unfortunately. Especially with multichannel… which doesn’t affect you though