KVR Audio

Liepa · Post by **Liepa** » Tue Mar 19, 2013 6:05 pm

Hi, I was looking for a fanless motherboard to build a programmable effects pedal. My requirements are quite specific - I don't need a GUI (I'm going to run gui-less linux on it, probably Gentoo) but I need low latency sound input/processing/output. I am planning to run pure data on the system as the main application to process sound. I was looking at the fanless Mini itx boards but they have so much on them, especially for video, that they might be a bit of an overkill. Are there any other motherboards that I should look into? Any DSP oriented ones? I am aware that for some of them I would need an additional sound card.

I already have a Raspberry Pi that I might end up using, but it doesn't have audio input (only audio output). That means I need to use an external sound card. If I got a USB external sound card I could sort out the sound input but the latency might be too much for real time effects. Also, Raspberry Pi has a DSP processor but it's impossible to use currently. Has anyone accomplished low latency real time audio in/out on Raspberry Pi?

Thanks.

skitchy · Post by **skitchy** » Wed Mar 20, 2013 4:23 am

I was going to say Raspberry Pi - I have seen a guy making FX pedals with one using Puredata somewhere. I dont have a link but it shouldn't be hard to find.
That being said, the RasPi has opened the door for tiny Linux computers. This one costs about £15 more https://www.olimex.com/Products/OLinuXi ... OLinuXino/ and it has a mic input, more IO, and more power.
The main thing about the Pi though is that it has the community behind it.

AdmiralQuality · Post by **AdmiralQuality** » Sat Mar 23, 2013 3:28 am

skitchy wrote:I was going to say Raspberry Pi - I have seen a guy making FX pedals with one using Puredata somewhere. I dont have a link but it shouldn't be hard to find.
That being said, the RasPi has opened the door for tiny Linux computers. This one costs about £15 more https://www.olimex.com/Products/OLinuXi ... OLinuXino/ and it has a mic input, more IO, and more power.
The main thing about the Pi though is that it has the community behind it.

What are people using for an audio digitizer input on the R-Pi?

AutoStatic · Post by **AutoStatic** » Mon Mar 25, 2013 9:36 pm

Liepa wrote:Has anyone accomplished low latency real time audio in/out on Raspberry Pi?

Raspberry Pi and real-time, low-latency audio

skitchy · Post by **skitchy** » Tue Mar 26, 2013 1:31 pm

AdmiralQuality wrote:
What are people using for an audio digitizer input on the R-Pi?

Any USB audio interface that has good enough drivers, I think.

AdmiralQuality · Post by **AdmiralQuality** » Tue Mar 26, 2013 8:49 pm

skitchy wrote:
AdmiralQuality wrote:
What are people using for an audio digitizer input on the R-Pi?
Any USB audio interface that has good enough drivers, I think.

That's a darned shame.

skitchy · Post by **skitchy** » Tue Mar 26, 2013 9:43 pm

Why's that Admiral? (Just wondering what you have in mind)

AdmiralQuality · Post by **AdmiralQuality** » Tue Mar 26, 2013 9:52 pm

skitchy wrote:Why's that Admiral? (Just wondering what you have in mind)

The obvious. Synths and effects (even guitar pedals) with $35 innards. Adding a USB audio interface makes it far less simple and graceful and at least doubles the cost. (Also I've read that it's USB 1.1 only, no USB 2.0!)

I still intend to see if I can make a synth out of one with no additional parts (other than connectors, of course). Though I'm so busy I wonder if I'll ever get around to it.

AutoStatic · Post by **AutoStatic** » Tue Mar 26, 2013 10:53 pm

AdmiralQuality wrote:(Also I've read that it's USB 1.1 only, no USB 2.0!)

The ports on the RPi are USB2.0.

AutoStatic · Post by **AutoStatic** » Tue Mar 26, 2013 10:55 pm

AdmiralQuality wrote:What are people using for an audio digitizer input on the R-Pi?

Edirol UA-25. But any USB1.1 class compliant audio device should work. I've also got a Berhinger UCG102 clone, unfortunately it was dead on arrival.

Ch00rD · Post by **Ch00rD** » Tue Mar 26, 2013 11:24 pm

Liepa wrote:Hi, I was looking for a fanless motherboard to build a programmable effects pedal. My requirements are quite specific - I don't need a GUI (I'm going to run gui-less linux on it, probably Gentoo) but I need low latency sound input/processing/output. I am planning to run pure data on the system as the main application to process sound. I was looking at the fanless Mini itx boards but they have so much on them, especially for video, that they might be a bit of an overkill. Are there any other motherboards that I should look into? Any DSP oriented ones? I am aware that for some of them I would need an additional sound card.

I already have a Raspberry Pi that I might end up using, but it doesn't have audio input (only audio output). That means I need to use an external sound card. If I got a USB external sound card I could sort out the sound input but the latency might be too much for real time effects. Also, Raspberry Pi has a DSP processor but it's impossible to use currently. Has anyone accomplished low latency real time audio in/out on Raspberry Pi?

Thanks.

[OT] This post reminds me of the infamous CrucFX-1000.

AdmiralQuality · Post by **AdmiralQuality** » Tue Mar 26, 2013 11:48 pm

AutoStatic wrote:
AdmiralQuality wrote:What are people using for an audio digitizer input on the R-Pi?
Edirol UA-25. But any USB1.1 class compliant audio device should work. I've also got a Berhinger UCG102 clone, unfortunately it was dead on arrival.

I used to have a UA-5. They cost over $100. (Discontinued now but there's equivalent products, still they won't fit in a guitar pedal.)

And please don't say the B-word.

AdmiralQuality · Post by **AdmiralQuality** » Wed Mar 27, 2013 12:05 am

AutoStatic wrote:
AdmiralQuality wrote:(Also I've read that it's USB 1.1 only, no USB 2.0!)
The ports on the RPi are USB2.0.

I read that on the link that was posted above.

http://wiki.linuxaudio.org/wiki/raspberrypi

Supported USB devices

USB1.1

Any class compliant USB1.1 audio interface will work with the RPi. You can determine if a device is class compliant if the specifications of the interface state that no drivers are needed when using Mac or Windows. If unsure several listings of supported interfaces are available:

http://wiki.linuxaudio.org/wiki/current_audio_gear
http://wiki.linuxmusicians.com/doku.php ... are_matrix
http://elinux.org/RPi_VerifiedPeriphera ... ound_Cards (RPi specific)
USB2

It is currently unclear if any USB2 audio interfaces work with the RPi.

skitchy · Post by **skitchy** » Wed Mar 27, 2013 12:28 am

There are a virtually unlimited number of very cheap USB audio 'sticks' on ebay et al that *might* work with the Pi for such a task (I've had this sort of thing in mind for some time too). I have one that cost about £6 and I know the output works at the very least - never tried anything with low latency or input though.

Liepa · Post by **Liepa** » Wed Mar 27, 2013 1:00 am

Hi everyone, thanks for all of your advice. I'll probably stick with Raspberry Pi for now. I've bought Behringer U-Control UCA222 and will try to use the gui-less version of Gentoo and Pure Data to leaver the OS of GUI handling. If anybody's interested I can update this thread with the progress

also, why did someone call CrucFX-1000 infamous...? I do think it looks a bit silly with that massive keyboard and the screen - if you have an effects pedal and you want to use it in live performances you will probably not gonna program live cause you are gonna have enough work playing the instrument that you are feeding into the pedal

Fanless motherboard to build gui-less programmable effects pedal