LPC: The past, present, and future of Linux audio [LWN.net]

LPC: The past, present, and future of Linux audio

Posted Oct 7, 2009 18:02 UTC (Wed) by cventers (guest, #31465)
Parent article: LPC: The past, present, and future of Linux audio

One user's opinion:

I do a lot of mixing with the excellent xwax, and I'm also getting into music production. This follows years of using Linux as my primary desktop.

ALSA used to frustrate me, just because it was another thing that didn't always work "just right" out of the box. I've been less than impressed by reliability problems I've had with Intel HDA audio in the past, especially the fact you often have to tell the driver how the card is wired and experiment with different module loading options to get it to work. There may be a good hardware reason for this, but since most hardware works out of the box with Linux these days, the little bit that doesn't really stands out.

I gave Linux a shot for music production but left it behind and began using Windows for that purpose alone. It's actually the first use for Windows I've found in years. I don't blame this on sound in Linux; rather, the stability and quality of some of the open-source tools isn't quite what I might wish it to be, and although there are ways to use VSTs under Wine, there is nothing dependable and functional enough for serious, heavy and everyday use. So for the first time in years, I dual-boot so that I can use a big heap of proprietary software to compose music.

All of that said, when it comes to Vinyl Emulation, I couldn't imagine using anything but xwax + ALSA + Linux. I've read the xwax source code, and while it's not the prettiest I've seen, the author clearly understood how to write simple, reliable, real-time programs. ALSA is great because it supported my USB preamp out of the box, and provided a simple mechanism (asoundrc) where I could apply software gain to assist xwax in better tracking the timecode. udev lets me plug in the USB preamp wherever I want and makes sure it will pick the same device nodes, which is *not possible* with Windows and ASIO. This solution also lets me run with 100% reliability at 2 ms latency, which is great for live mixing.

Frankly, I wouldn't trust Windows with live mixing. I tried the Torq software that came with my preamp, and it seemed like a big, bloated mess... but didn't even work on more than one occasion, even when the hardware was configured precisely as it is when I use it in my Linux environment. Moreover, you can't achieve the same low-latencies with Windows, and I have in fact seen a BSOD in one of my production sessions.

With a handy mlockall() added to the xwax source code, and the fact that it buffers tracks into RAM that are decoded by external command-line utilities, my system *should* keep playing, even if the hard drive (with swap!) crashes, at least until the current tracks are over. Anyone trust Windows to do the same?

As an amateur musician, I should have an opinion about the state of affairs on OS X, but I don't because I'm not fond of microkernel performance, solid-gold prices and extremely basic user interfaces. :p

to post comments

LPC: The past, present, and future of Linux audio

Posted Oct 7, 2009 18:32 UTC (Wed) by drag (guest, #31333) [Link] (3 responses)

Well the fact is that OS X does not use a Microkernel and never did. It was a lie. To keep the Apple reality distortion bubble from popping people have created the concept of 'hybrid microkernel' to describe the OS X kernel as if that was some sort of CS concept.

Which all that it means is that Apple copied the NT kernel design approach by incorporating some features of microkernels into what ends up being fundamentally a monolithic design.

But as far as audio stuff goes I am told that Apple's CoreAudio is actually a compelling feature over what is available in other operating systems. It's designed with music production in mind.

--------------------------

To get the best out of Linux it is still very tedious and highly technical.

It involves:

* Installing and configuring Jack
* Configuring your applications to use Jack
* Purchasing a audio card with good performance characteristics. (Intel-HDA, while it is fine for music playback, is not designed for low-latency performance regardless of what drivers you use on it)
* Installing a custom OS kernel with *-rt patches.

And a great deal of learning the ins and outs of how to manage all the above.

Generally the biggest difference between the the actual workflows of Linux vs Windows is that instead of using big music production apps with plugins you use a lot of smaller applications chained together through Jack.

Now keep in mind that it has been a _long_ time since I mucked around with this stuff.

But I have a simple piano-style M-audio midi controller. It connects to the PC using a USB connection.

So the workflow went like this:

USB Controller -(jack midi routing)-> Software Synth (I forget which) -(pcm audio routing)-> Alsa Modular Synth (for effects processing) -(pcm audio routing)-> volume controls -(pcm audio routing)-> digital out on my sound card --> digital receiver --> speakers.

All in all I got the system to reliably operate to the point were I could not notice a delay from when I press a key to when I heard the sound.

Of course this required a couple hours of mucking around and setup. Debian by default could barely do software synth on it's own before I started customising it.

The situation has improved somewhat with the introduction of custom Linux variants in the form of 64Studio and Ubuntu Studio and things of that nature. So at least the software setup is mostly taken care of.

LPC: The past, present, and future of Linux audio

Posted Oct 7, 2009 18:57 UTC (Wed) by cventers (guest, #31465) [Link]

Perhaps not, I don't remember all of the technical details, but I do remember the funnel lock. That was enough to keep me away from it at the time.

And you're absolutely right about the tedious nature of setup on Linux. I too have a MIDI USB controller from M-Audio, and I too got it working under Linux (actually even patched into reFX Vanguard courtesy of dssi-vst). But what I found is that when musical inspiration hits, I want to spend the least amount of time possible getting into working music software, because it generally doesn't survive having to debug some arcane software issue.

LPC: The past, present, and future of Linux audio

Posted Oct 7, 2009 18:58 UTC (Wed) by jebba (guest, #4439) [Link] (1 responses)

I appreciate that it may be pretty hard to get jack/rt going using some approaches (e.g. older debian). But a fedora(ish) install with planetccrma packages (including kernel) make it quite easy. I have repeatedly read that Intel HDA can't be used with realtime, but I have used it successfully on various EeePCs and my thinkpad. It seems that the package defaults are more reasonable now--with F11 and the thinkpad I basically just installed the ccrma packages, started up qjackctl and it "just worked".

LPC: The past, present, and future of Linux audio

Posted Oct 7, 2009 19:20 UTC (Wed) by drag (guest, #31333) [Link]

It's gotten better.

But for best performance you still need to patch and recompile your kernel as well learn the in-and-outs of dealing with the multiple Linux user interfaces.

With my setup I was getting pretty reliable sub-10msec latencies with Jack's settings with no xruns, although I usually let things slide to 60-70 just so I could have more responsive system.

The other thing that sucks about Intel HDA (besides the low quality of digital-analog conversion chips and relative high buffer requirements) as far audio creation stuff is concerned is just the lack of I/O options. This is the biggest real difference between 'profesional' and 'consumer' audio hardware. My old M-Audio Audiophile 24/96 has Analog stereo in, stereo out, digital in, digital out, and midi in and midi out. It also has nice-quality D-A/A-D conversion and the difference is enough that a with a quiet room and nice headphones pretty much anybody can tell the difference.

But, of course, that's PCI.

Otherwise I have no problems with using Intel-HDA for anything. It's the sound card I use the most since that is what is on my laptops. For music playback and doing some recording stuff it's perfectly fine and unless you are in a quiet area with high quality headphones the chances of anybody being able to the the difference is very unlikely.

LPC: The past, present, and future of Linux audio

Posted Oct 29, 2009 18:08 UTC (Thu) by jrigg (guest, #30848) [Link]

Quote:
I gave Linux a shot for music production but left it behind and began using Windows for that purpose alone. It's actually the first use for Windows I've found in years. I don't blame this on sound in Linux; rather, the stability and quality of some of the open-source tools isn't quite what I might wish it to be, and although there are ways to use VSTs under Wine, there is nothing dependable and functional enough for serious, heavy and everyday use. So for the first time in years, I dual-boot so that I can use a big heap of proprietary software to compose music.

Another user's perspective:
I've used Ardour on Linux for music recording for a few years now. I suspect I'm one of a relatively small number who use it for paid work, but I've found it to be very solid and reliable for multi track recording and editing. The current lack of "pretty" plugin GUIs is a positive advantage to me (few things are more disruptive to work flow than having to turn a picture of a knob with a mouse). Those who need good MIDI support might still be better off with Mac or Windows, but I don't require this. I would say stability of my system is noticeably better (for straightforward recording and editing) than that experienced by many of my Mac- and Windows-using colleagues.

One area that still needs improving is using multiple sound cards to boost channel count. In my mobile system I use an RME MADI card (up to 64 channels of simultaneous in/out at 48kHz) with external AD/DA converters, but that is probably too expensive an option for most semi-pro and hobby users. Combining a few eight channel cards for a cheaper setup still requires jumping through difficult configuration hoops (so difficult that AFAIK none of the dedicated media distros come with configurations for doing this).