Focusrite Clarett USB

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trrichard
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Joined: Thu Sep 07, 2017 6:51 am

Focusrite Clarett USB

Post by trrichard »

I just got my Focusrite Clarett 4 Pre USB yesterday and unpacked it. Out of the box testing shows the following in ubuntu studio 16.04

Works:
- Sample Rate of 48000
- Mic Preamps

Not Working:
- Sample Rates >= 88200. I get a ton of xruns
- Alsa Mixing (I'm picking up only one element which is Clock source)


Does anyone else have one? How is it working for you?
I'm looking at the driver for the first gen scarlett but I've heard it's pretty different from second gen. I think it's likely that the clarett is pretty different as well. I'm going to *try* to start fixing the kernel module for it but I need to fix up a windows partition before I can do any USB snooping.
trrichard
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Re: Focusrite Clarett USB

Post by trrichard »

First odd thing I'm seeing at 96khz. Looks like I'm getting negative xruns....

Code: Select all

Jack: JackClient::ClientNotify ref = 3 name = qjackctl notify = 3
Jack: JackClient::kXRunCallback
Tue Jul 31 23:40:56 2018: Jack: **** alsa_pcm: xrun of at least -18501806.080 msecs
Tue Jul 31 23:40:56 2018: Jack: ALSA XRun wait_status = 0
Tue Jul 31 23:40:56 2018: Jack: JackSocketServerChannel::Execute : fPollTable i = 1 fd = 12
Tue Jul 31 23:40:56 2018: Jack: JackRequest::Notification
Tue Jul 31 23:40:56 2018: Jack: JackEngine::ClientNotify: no callback for notification = 3
Tue Jul 31 23:40:56 2018: Jack: JackEngine::ClientNotify: no callback for notification = 3
Tue Jul 31 23:40:56 2018: Jack: JackClient::ClientNotify ref = 2 name = dbusapi notify = 3
Tue Jul 31 23:40:56 2018: Jack: JackClient::kXRunCallback

One more odd symptom in 96khz. If the Audio is changed from Duplex using only the input or only the output channels the Clarett seems to work fine without any xruns. It seems like only when jack is running with the clarett as both the input and output device that it has xrun problems.

I'm becoming more convinced there is a problem at the Alsa PCM layer.
trrichard
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Posts: 9
Joined: Thu Sep 07, 2017 6:51 am

Re: Focusrite Clarett USB

Post by trrichard »

I've returned the Clarett in favor of getting a Scarlett 18i8.

Of course the 18i8 is experiencing a very similar problem. I'm not sure why yet. This same OS was doing fine with the previous generation of Scarlett. So, more investigation...
puleglot
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Re: Focusrite Clarett USB

Post by puleglot »

For both devices (Clarett 4Pre USB and Scarlett 18i8) you need to explicitly set the correct number of input channels, because not all combination of sample rates and channels count will work. You can also try the patch below:
https://git.kernel.org/pub/scm/linux/ke ... 88f5bb0b23
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