Support of audio interfaces under Linux

Talk about your MIDI interfaces, microphones, keyboards...

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asbak
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Re: Support of audio interfaces under Linux

Post by asbak »

The kernels I mentioned in the test above aren't RT nor patched for RT.
One is the default Jessie offering which installed with the OS (3.16) and the other one I compiled. (3.18 PREEMPT 1000 mHz)

As for what we are allowed or not allowed to tell newcomers about technical issues, I frankly wish somebody was around to tell me 1/2 this stuff because much of the information out there just isn't realistic, it's vague, often contradictory (although not necessarily incorrect) and applies to specific kinds of situations in which nobody envisaged trying to extract maximum performance but rather just wanted something that worked on some kind of basic level.

To me such an approach makes no sense at all. This website is called "linuxmusicians" after all so the basic assumption is that the intended audience is some kind of "musician".

If one goes on gearslutz etc their idea of "musician" appears to be a DJ or a glowstick waving EDM clown who can hit the spacebar on a $2000 Macbook (excluding add-ons) to start an mp3 player but to me the term "musician" means somebody who plays an instrument of some sort or somebody who at least has some kind of basic understanding or intention to learn about music related arranging and performance.

The next logical conclusion is that in order to make "musician" type use of Linux it needs to perform to a certain basic specification. What's the point having a system which cannot process low-latency audio? All you end up with is some kind of simulator of an audio workstation where you get a vague idea of how to use software but which is unusable for any kind of live usage, for example, guitar fx processing. There's a reason why Steinberg developed ASIO and why CoreAudio on OSX allows hardware & software to operate with low-latency. It would be ridiculous to forego this on Linux.

So therefore, how could it possibly make sense to keep people in the dark about this. I tried every trick in the book to get decent performance out of my system and kept failing, not being sure why even though I guessed at the reasons but put off making those changes for last because of the supposed "hassle of compiling a kernel" type issues. All those attempts to get things to a working low latency state failed miserably. In the end it was the damn kernel. I'd be quite interested to know who out there are willing to disprove this or present hard evidence instead of vague "so and so said that blah blah" type theories.

I presented hard facts and test results and those results don't lie. The standard Debian kernel sucks for Linux Audio, it's a fact. Maybe some other Linux OS's or distros have better default options available, I don't know. Keeping people in the dark about this issue doesn't do them any favours. I wish I'd known these things for a fact ages ago instead of being fed all kinds of vague and contradictory info, often by people who have no use for low-latency work and who probably don't even know what it is. I'd have been grateful if somebody'd bothered to confirm to me that Linux Audio with a standard kernel doesn't pass muster just like a Windows audio card without proper ASIO or WDM drivers or whatever just won't perform either. Then I wouldn't have had to waste time attempting other kinds of fixes which had little to no overall impact.

The facts as I see them are that without a PREEMPT or RT Kernel you're out of the game before it's even started and witholding this kind of information from people ain't doing them no favours. It's like telling somebody not to install ASIO drivers on their WIndows PC because it's too complicated and that they should rather just be happy and satisfied with loads of Xruns.

The Linux kernel situation again varies from distro to distro. Some may already have readily available or default PREEMPT type kernels or even RT kernels. Some don't. Without knowing about and understanding this concept things just descend into mythical confusion and lack of understanding about why system A works nicely yet system D doesn't.

Compiling and installing kernels ain't hard. If one can follow basic instructions and learned to copy and paste it's achievable. Ditto if someone didn't want to do this and rather wanted to make use of something like Liquorix's repository and installed them from there.

I'd be interested in being proven wrong about this low-latency performance issue by anybody who can present credible evidence and test results to the contrary.
Some Focal / 20.04 audio packages and resources https://midistudio.groups.io/g/linuxaudio
ssj71
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Re: Support of audio interfaces under Linux

Post by ssj71 »

I don't want this to get out of hand. I should not have commented. Its a minor detail that has little to do with the real thread topic here. Apologies. If you'd like to discuss this more lets open a new thread.
Last edited by ssj71 on Fri May 01, 2015 7:01 pm, edited 1 time in total.
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asbak
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Re: Support of audio interfaces under Linux

Post by asbak »

No worries.
Some Focal / 20.04 audio packages and resources https://midistudio.groups.io/g/linuxaudio
glowrak guy
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Re: Support of audio interfaces under Linux

Post by glowrak guy »

http://puppylinuxstuff.meownplanet.net/10wt3ch/

There is a 400 meg iso here for PuppyStudio3.3RT

Burn the iso, reBoot into the cd, the OS loads in ram, and at shutdown,
asks if you want to create a savefile, (squashfs) to keep settings
for future sessions. The system has zynaddsubfx, hydrogen,
and audacity, so you can test an RT sysyem, without
having to configure things.

There is a much newer commercial version available,
if you like it. http://www.getstudio1337.com/
Cheers
tramp
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Re: Support of audio interfaces under Linux

Post by tramp »

ssj71 wrote: More to my point, I just don't think we should tell every person coming to linux audio "the first thing you should do is go compile your own kernel" (which maybe you weren't suggesting that; I don't know where you got your kernel). It really proliferates the stereotype that linux is only for pale-faced coders alone in the dark of their lonely apartments, lit only by the monitor. If you'd suggest an easy way to get an RT kernel I wouldn't have commented (and I'm curious to see what you say).
If, you would squeeze the last bit out of your PC for audio performance, you need to build your own kernel. And be it alone for set the CPU from general to your host CPU. That's a matter of fact, and I didn't see a reason why not to say that.
It's one of the advances of Linux, and open source in general, that you could do that.
If you've done it once, you will be surprised how easy it is, and will be a bit more open minded about what Linux is.

Okay, it's for sure not the first thing you have to do when you come to linux, but sooner or later, you must go this route, otherwise you will never know, what your PC is able to do.
On the road again.
ssj71
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Re: Support of audio interfaces under Linux

Post by ssj71 »

ok. ok. I was wrong. Sorry for the noise.
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tatch
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Re: Support of audio interfaces under Linux

Post by tatch »

not to continue being off-topic but i don't think you're wrong ssj71. not everyone wants or needs to achieve extraordinary latency, especially with computer-generated music. I'm actually often at 32ms, which isn't fantastic but it's not bad either. It's nice that you can push that number down but compiling an RT kernel takes a long time and always ends up breaking something for me, like my card reader will stop working or I won't be able to suspend anymore (true stories). Plus I always forget how to do it so I have to dig up documentation every time for both compiling the kernel and applying the rt patch, and right after I do it another kernel update gets released that is supposed to be X times better than the current one and so on. It's kind of a hassle so i prefer to use kxstudio's precompiled lowlatency kernel.
ssj71
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Re: Support of audio interfaces under Linux

Post by ssj71 »

tatch wrote:i prefer to use kxstudio's precompiled lowlatency kernel.
me too.
_ssj71

music: https://soundcloud.com/ssj71
My plugins are Infamous! http://ssj71.github.io/infamousPlugins
I just want to get back to making music!
andredaflauta
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Re: Support of audio interfaces under Linux

Post by andredaflauta »

I can get a Behringer UMC204HD for under 100 euro (which I think is a good deal), but since is new, there isn't any info about linux usage.
The device is usb2.0, but is class-compliant (it says on the Behringer page because of Mac compatibility). I wouldn't mind being the first to test an interface on linux, but I need it to have a good chance of working.
Or you could tell me another usb interface for less than 100 euro that has, at least 2 mic/instrument inputs, midi, trs outputs. I already know the alesis IO2 express, but I've being reluctant on buying it for some time, so I'd really like to have an alternative, also not alternatives over 100 euros, unless they are something not generally known (so, no scarletts and stuff like that).
asbak
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Re: Support of audio interfaces under Linux

Post by asbak »

I have a class compliant Behringer UMC404 (which should be similar to the 204) which works OK under Linux using a self-compiled 1000Hz PREEMPT Kernel, frames set to 64 giving 4ms latency.

Having said that, in the past I have had issues with this interface on other computers but there are so many variables involved ie different Operating systems, different kernels, different configurations, different firmware version on the unit etc that I can't be sure anymore whether it was the hardware or whether something else was misconfigured.

Config that works for me:

Gigabyte X58 + i7
UMC404 flashed with latest firmware (this may be important because this *may* have been the reason why I had problems in the past with this unit under Linux)
UMC404 plugged into a USB2 port (USB3 may give issues from what I recall)
Mint 17.2 64bit (Any Debian derived Linux should be OK, I don't have experience using other distros for audio work)
PREEMPT 1000Hz Kernel, alternatively the Ubuntu "lowlatency" kernel will hopefully work reasonably well.

Code: Select all

apt-cache search lowlatency
Tune settings as per the usual guides
Last edited by asbak on Wed Sep 23, 2015 10:33 am, edited 1 time in total.
Some Focal / 20.04 audio packages and resources https://midistudio.groups.io/g/linuxaudio
artek
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Re: Support of audio interfaces under Linux

Post by artek »

If one goes on gearslutz etc their idea of "musician" appears to be a DJ or a glowstick waving EDM clown who can hit the spacebar on a $2000 Macbook (excluding add-ons) to start an mp3 player but to me the term "musician" means somebody who plays an instrument of some sort or somebody who at least has some kind of basic understanding or intention to learn about music related arranging and performance.
Have you seen this forum?
asbak
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Re: Support of audio interfaces under Linux

Post by asbak »

:mrgreen:

Yeah ... well .... just in case there was still somebody out there who plays live instruments (guitar/bass fx, keyboards, EWI and so on) and/or needed low-latency audio then hopefully the information could be useful to them. It was obviously naive of me to assume that this is what most people required or wanted.
Some Focal / 20.04 audio packages and resources https://midistudio.groups.io/g/linuxaudio
artek
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Re: Support of audio interfaces under Linux

Post by artek »

Yeah ... well .... just in case there was still somebody out there who plays live instruments (guitar/bass fx, keyboards, EWI and so on) and/or needed low-latency audio then hopefully the information could be useful to them. It was obviously naive of me to assume that this is what most people required or wanted.
Why not the vendors should provide such a information? What is wrong with them?
Is it very hard for them to test audio interface in ubuntu? Lack of interns?
Linux community have provided linux audio distributions, audio drivers, rt specialized kernel features 4free...
asbak
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Re: Support of audio interfaces under Linux

Post by asbak »

Why not the vendors should provide such a information? What is wrong with them?
Vendors are not interested in supporting Linux or the BSD's. Vendors (mostly) only support OSX and Windows.
Is it very hard for them to test audio interface in ubuntu? Lack of interns?
No but it costs engineering hours to test and develop products. Vendors (mostly) don't want to spend the time and money getting their products to work under Linux or BSD's.
They assume (probably correctly) that most people will buy a Mac or use Windows.
Linux community have provided linux audio distributions, audio drivers, rt specialized kernel features 4free...
Makes no difference to the hardware vendor.

That said, some vendors have been helpful and provide limited assistance.

As far as I can determine if an audio interface is class compliant there's a good chance it will work under Linux. If it requires special software to perform audio routing then obviously this will not be available unless the vendor releases Linux software for the product. Some RME devices will work because people wrote custom software to make this work.

Anyway, best bet is to check the device compatibility matrix to see if a device is listed. Unfortunately many of these lists are not up to date.

http://www.alsa-project.org/main/index.php/Matrix:Main
http://alsa.opensrc.org/Sound_cards
http://wiki.linuxaudio.org/hw/start
Some Focal / 20.04 audio packages and resources https://midistudio.groups.io/g/linuxaudio
artek
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Re: Support of audio interfaces under Linux

Post by artek »

Vendors are not interested in supporting Linux or the BSD's. Vendors (mostly) only support OSX and Windows.
Also, thanks to "interns" vendors support android and hence support linux.
No but it costs engineering hours to test and develop products. Vendors (mostly) don't want to spend the time and money getting their products to work under Linux or BSD's. They assume (probably correctly) that most people will buy a Mac or use Windows.
It's pure injustice, that everything rest on shoulders of community.
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