Scarlett 18i8 3rd Gen - constant click noises but no xruns

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marcod2
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Scarlett 18i8 3rd Gen - constant click noises but no xruns

Postby marcod2 » Wed Oct 30, 2019 2:02 pm

Hi all,

been lurking on the forum for a while. Thanks for the great conversations! I'm an experienced Linux Audio user and have utilised a a fair amount of soundcards on Linux systems.
I've read most of the Scarlett 2nd Gen. post I could find here and elsewhere, and noticed there's little info about the 3rd Gen.
I'm taking this chance to share my experience with a 18i8 3rd Gen. and see if my problem can be solved.

SPECS:
I'm on a DELL M4800 Precision, Linux Mint 19 with Cinnamon, kernel 4.15.0-66-lowlatency.
Soundcard: Focusrite Scarlett 18i8 3rd Generation.

After the necessary tricks to force the soundcard out of MSD Storage mode, now the device is recognised by and fully functioning with both Pulseaudio and Jackd. However.....

PROBLEM:
When using the soundcard (either via Pulseaudio or via Jackd), I can hear click noises at what seem almost regular intervals. The clicks vary in loudness (some are very loud, other almost unnoticeable). Independently from the CPU or Disk usage, the clicks are always there, making the soundcard effectively unusable.

Interestingly, when using the card via Qjackctl I see no XRuns, but I do clearly hear the clicks.

ACTIONS TAKEN:
I excluded a defected soundcard, broken USB cable or USB port issues (sometimes USB3 can cause troubles) because when using the soundcard on a Windows partition on the same computer, the sound is clean, no clicks. Although, perhaps I'm missing something here.

Running realTimeConfigQuickScan gives me a mostly positive check, the only "not good" items are the following ones:
- Checking swappiness... 60
- Checking checking sysctl inotify max_user_watches... < 524288
- Checking access to the high precision event timer... not readable
- Checking access to the real-time clock... not readable
- Kernel with Real-Time Preemption... not found

these "not good" items have always been the same on my laptop, and they never gave me troubles with two other soundcards. I've also read on the ConfigQuickScan page that - except Swappiness - the other items are not so important these days any more. So I'm assuming the clicks with the Scarlett 18i8 3rd Gen. are likely not related to any of those items. But I may be wrong...

Does anyone have any hint on the issue? Or other things I could check?

thanks in advance,

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bluebell
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Re: Scarlett 18i8 3rd Gen - constant click noises but no xruns

Postby bluebell » Sun Nov 03, 2019 10:09 am

marcod2 wrote:PROBLEM:
When using the soundcard (either via Pulseaudio or via Jackd), I can hear click noises at what seem almost regular intervals. The clicks vary in loudness (some are very loud, other almost unnoticeable). Independently from the CPU or Disk usage, the clicks are always there, making the soundcard effectively unusable.

Interestingly, when using the card via Qjackctl I see no XRuns, but I do clearly hear the clicks.


Try a rate of 48000 if you use another.
Linux – MOTU UltraLite AVB – Qtractor – https://soundcloud.com/suedwestlicht

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wjl
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Re: Scarlett 18i8 3rd Gen - constant click noises but no xruns

Postby wjl » Sun Nov 03, 2019 11:57 am

Hi Marco,

your user is in the audio group, and that group has access to realtime? Also, did you have the same problem with other interfaces, like the 2nd gen ones?

Cheers,
Wolfgang
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marcod2
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Re: Scarlett 18i8 3rd Gen - constant click noises but no xruns

Postby marcod2 » Sun Nov 03, 2019 5:24 pm

Try a rate of 48000 if you use another.


Thanks Bluebell, it was at 44100, now I've changed it to 48000, but the problem persists.

Thanks Wjl, Yes I'm in the audio group, and the group has access to realtime; my audio.conf says:
@audio - rtprio 95
@audio - memlock unlimited

I haven't tried a 2nd gen yet, not sure if I can find one, but I'll try.
I've been using a Scarlett 8i6 (the model made around 2012) for many years without issues.

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bluebell
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Re: Scarlett 18i8 3rd Gen - constant click noises but no xruns

Postby bluebell » Sun Nov 03, 2019 8:49 pm

marcod2 wrote:PROBLEM:
When using the soundcard (either via Pulseaudio or via Jackd), I can hear click noises at what seem almost regular intervals. The clicks vary in loudness (some are very loud, other almost unnoticeable). Independently from the CPU or Disk usage, the clicks are always there, making the soundcard effectively unusable.

Interestingly, when using the card via Qjackctl I see no XRuns, but I do clearly hear the clicks.


Do you use jack_bufsize to change buffer size on the fly? If yes then try using the correct buffer size when starting jackd and don't change it on the fly. Are the clicks still there?
Linux – MOTU UltraLite AVB – Qtractor – https://soundcloud.com/suedwestlicht

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Re: Scarlett 18i8 3rd Gen - constant click noises but no xruns

Postby JamesPeters » Sun Nov 03, 2019 9:33 pm

I have a 3rd gen 2i2 that I got a week ago, and it's working well. Currently I'm using Xubuntu 19.10 with realtime kernel 5.3.0-19 (also tested in Lubuntu 19.10 with same kernel).

The only time I hear a click is when switching sample rates. This applies to when a Youtube video is 48 KHz, after having played an audio file from my computer at 44.1 KHz (or using a Reaper project at any other sample rate), so basically any time there's a sample rate change. It's not loud but I do notice it.

I had tried all kinds of optimizations for audio in Linux, and run test projects in Reaper to verify the results. I discovered that most the things people say should be done to optimize for audio performance aren't necessary for me, at least with recent kernels and using Reaper. Under high CPU testing in Reaper, I've found that sometimes it might make performance worse if I do some of those tweaks (not by a lot, but still). Maybe this is just how it works if you're using Reaper as a DAW. I wouldn't necessarily recommend it to people using other DAWs. But I did want to mention what has been done to configure my system for audio...which is "not a lot". Reaper works directly with ALSA or with Jack, and I get better results with ALSA but I'm being picky since I test it under ridiculous test conditions. I expect Jack would work better if I did some of the other recommended tweaks to the system, but I don't need Jack for anything.

Here are the changes I made to the distro:

-install low latency kernel
-change the vm.swappiness to 10 (it seems to help with really large Reaper projects and lots of CPU use, to some degree),
-set my CPU governor to "performance" when I'm running Reaper projects (using indicator-cpufreq),

Then these other more basic things:

-disable xiccd in session startup (color managment for monitors in Xubuntu, which seems unnecessary and took extra cpu),
-disable the bluetooth manager in session startup,
-turn off the screen saver and power management (I let them start in the session but they're set to not do anything, which seems better than just not letting them start at all).

At 44.1 KHz I can set the buffer in ALSA (and Jack) to 32 samples and 4 blocks for most projects (2.9 ms round-trip latency) without xruns (or any distortion that doesn't register as an xrun for that matter), and I use 5 blocks of 64 samples (7.2 ms round-trip latency) for really demanding projects. That's about as high a buffer setting as I need.

All that being said: if I've heard any click/pop in the sound which wasn't a change in sample rate or xrun that I forced during testing, if anything it's very few. My audio system sometimes does make the odd tiny click sound (approximately once a day) but I can't nail down what that's from; it could be something in the electrical system for all I know, and I think I've heard it with other audio devices too.

Have you tried plugging the device into other USB ports? There are "internal hubs" on your mainboard that connect USB ports (if you see a pair side-by-side, chances are they're paired on a hub), so the USB port for the device is possibly being shared with another device on the same hub "invisibly". (And if you're using any kind of external hub, that's probably not a good idea in general.) You said the particular hardware configuration works in Windows, but perhaps some resources are being assigned differently in Linux, so I figured I'd mention it just in case.

By the way I got the 2i2 out of MSD Storage mode the way they recommend, by using it on a Windows 7 machine. I thought that was a bit ridiculous to have to do (to get rid of that annoyance) but I still have an old laptop with Windows 7 so I used it to do that. Also I find it a bit much that they cripple the sample rate selection to 44.1 KHz / 48 KHz in the Windows driver unless you register (or read through the manual to find the workaround). It seems they really want people to register.

I'm curious how you got yours out of MSD Storage mode, and also are you able to select "air" and "pad" on the device from Linux? Alsamixer (etc.) doesn't show any options for the 2i2, but I have hardware buttons for all the necessary controls on the 2i2.
Last edited by JamesPeters on Wed Nov 06, 2019 1:43 am, edited 1 time in total.

marcod2
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Re: Scarlett 18i8 3rd Gen - constant click noises but no xruns

Postby marcod2 » Tue Nov 05, 2019 10:24 am

Hi bluebell,
Do you use jack_bufsize to change buffer size on the fly? If yes then try using the correct buffer size when starting jackd and don't change it on the fly. Are the clicks still there?


No I don't use jack_bufsize, I'm actually using Qjackctl for now.

Hi James,

thanks for sharing your experience, good to know the 3rd gen works for you. Then my problem is more likely with my setup.
The only difference I can see between ours setup is the kernel; I have a low-latency kernel and you have a RT one.

That said, I use another focusrite (1st gen.) with the low-latency kernel without issues. mmmh :?:
Also, I'm testing the click issue with daw and puredata producing a sinewave, so the cpu usage is very low.

I've tried different USB ports to no avail.

And yes, the MSD storage config., as well as all the startup procedure is quite annoying. I had to spend a lot of time with the support because I couldn't even run their software on my Windows partition (the issue was that a server.exe app needed by Focusrite Control won't run automatically).
To take it out of MSD mode i did the following:

Hold the 48V button down (the right one) while powering off the unit
Keep holding down 48V, turn the unit back on, hold for 10 seconds
Then power cycle the unit once more

Alsamixer doesn't show any option for the 3rd Gen, and the soundcard does not have hardware buttons, so I would have to switch to Windows if I wanted to change Air or Pad.
Funnily enough, alsamixer shows instead all kind of possible parameters for my 1st Gen Scarlett. Could this be some regression on how class compliant the new 3rd gen are?

This click problem is still a mystery to me. Any further questions or hint are highly appreciated! :D
I would rather spend time to fix the issue than selling the soundcard.

Thank you!

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Re: Scarlett 18i8 3rd Gen - constant click noises but no xruns

Postby JamesPeters » Wed Nov 06, 2019 12:31 am

Ah so there was a method of stopping that MSD storage configuration built into the hardware, not even mentioned in the manual. Thanks for mentioning that. This thread may help others using the 3rd generation Focusrite Scarlett series in the future, with info like that.

Oh by the way that workaround I'd found to enable all the sample rates in Windows: that wasn't mentioned in the manual for the 2i2, but was mentioned in the manual for the 2i2 Studio. Lol. I had to really dig. This kind of thing shouldn't be necessary. At least all the sample rates were exposed to ALSA in Linux, and that MSD storage configuration was only a bit of a nuisance.

Also I meant to say that I installed a low latency kernel, not a "realtime" kernel. I sometimes conflate the two.

I can't give any insight about the compatibility of the drivers (3rd gen versus 1st/2nd gen) but I did notice this:

https://www.linuxmusicians.com/viewtopi ... 95#p106095

I know that's for 2nd generation, but hopefully the 3rd generation devices will be supported at some point. I decided on the 2i2 partly due to the fact I didn't need any additional functionality beyond what's available by pushing buttons on the device. It'd be great if devices such as the 18i8 were 100% compatible with Linux.

The only other thing I can think of, for your issue: are your inputs being monitored through software somehow? Check the Pulse mixer and mute the inputs as a test, just in case. (Or turn those faders down.)

If I can think of anything else (beyond the obvious such as the condition of your USB cable, anything polling the USB bus, interference, etc.) I'll post again.

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Re: Scarlett 18i8 3rd Gen - constant click noises but no xruns

Postby marcod2 » Tue Nov 12, 2019 12:42 pm

Hi James, sorry I was away for the weekend.

Yes, I'm happy this thread can provide info for future users, and great to share experiences.
thanks for the link to the driver update, looks it has been merged into the kernel, so hopefully should land on my machine too.
While Alsamixer does not see any parameter for the Scarlett, Pavucontrol does see at least input and outputs levels and muting, that's already something.

As for my issue, I've followed your suggestion and tried to disable all inputs (of the Scarlett, but also the integrated sound card, you never know), but again, no luck. The clicks are still there.

I'll try to ask on the linux audio mailing list, see if anyone there has any hint.
This is becoming quite annoying, it's the first time in many years with linux audio that I encounter a bug that's so hard to fix!
Scarlett has always been my choice for Linux audio, in terms of quality/price/compatibility. But now I begin to reconsider.

Thanks all for the suggestions. If I find a solution to my issue I'll post it here.

And if anyone has a third generation device, it would be great to hear about your experience!

cheers,

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Re: Scarlett 18i8 3rd Gen - constant click noises but no xruns

Postby JamesPeters » Tue Nov 12, 2019 5:38 pm

Since I'm using a more current kernel than you, I wonder if that has something to do with it. Mint allows for swapping of kernels fairly easily, if I recall correctly from when I ran Mint. There's a provision in its "software sources" or something (I forget what it's called on Mint) where you can choose "view kernels" from the menu. From there you can install/remove various kernels. Then you can boot to whatever kernel from the grub menu (the newest kernel is chosen by default but the rest are left in the grub menu).

Also: I use xfce. I only briefly tried Cinnamon. I found xfce had more possibilities for customization (Cinnamon seemed surprisingly lacking by comparison after having used xfce) so I went back to xfce. It's proven to be a good base for a system that's not getting in the way of low-latency audio performance. Anyway maybe there's something about Cinnamon's configuratin which is involved in this. I'm reaching when I say that, but it might be worth considering. I know when I used KDE Plasma in a couple different distros, my system didn't perform quite as well (when I'm pushing the CPU close to 100% and using low-latency audio), and that's with the visual effects turned off. So there has to be something about the different DEs/WMs that can affect system performance.


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