low latency for embedded processing

[neebster]

Hello,

I'm looking for an economic solution for having low latency audio i/o with a single board computer, such as Raspberry Pi 2, BeagleBone Black, or Udoo Quad. My ultimate goal is to incorporate one of these into a (probably LM3886 based) amplifier, running a stripped-down linux, JACK, and Guitarix for emulation.

Now, I've achieved reasonable latency doing this with my 8 year old Dell PC's on-board connectors, but like I said, I want an embedded solution. It seems like the audio cape for BBB is not currently available, and I'm not entirely up for creating a custom-built interface using an I2S codec right now.

Any thoughts on the on-board sound for Udoo Quad? I've heard mixed things about the quality of sound, but this could just be people with poorly implemented software. I'm thinking an on-board solution *could* give me the option for a lower buffer size.

Then, there is USB audio. It seems in most cases that buffer sizes are limited to 64 bits at the smallest for many USB solutions. I'm wondering, has anyone had good luck running JACK with a USB device to achieve very low latency, economically? I want Guitarix to have <=5ms. Also, since budget is an issue (the rest of this project is not cheap), I'm looking for USB devices that are under $100, preferably under $60. Bitrate isn't a huge issue, 16 bit is OK. Also input for a high impedence source isn't a problem, I will take care of that externally.

Modules or small devices are better than large box solutions, as all this will be housed inside a chassis.

Any thoughts on what I/O device to use?

Thanks, all!

 

[tonitonitoni]

was trying to find solution to make pc based adjustable delay, for second line of speakers ,lowest possible latency with processing in vst i got was 100ms ,and thats with regular big components. not sure if it helps but try behringer uca202 ,uca222. its very small but still big latency

 

[neebster]

http://lac.linuxaudio.org/2014/papers/32.pdf suggests they got a Turtle Beach Amigo II to have acceptable ~5ms latency. I don't think it's impossible. 100ms is waaaay too high for my purposes.

 

[tonitonitoni]

yes but i think when they suggest 5ms that they are measuring direct input>output , but when you have software processing in between i think it all goes to hell

 

[neebster]

Truth. But I can't imagine a BBB doing that much worse than my dinosaur computer. And I'm at hardly perceptible levels of latency. Anyone else have experience with guitarix and SBC's? I'd think most of the newer quad cores would handle it just fine. Especially if I strip down the OS. I might even run the GUI from a separate computer.

 

[henrix]

Hi,

together with my professor I've created a multichannel i2s soundcard with software drivers for the BeagleBone Black/Green.
Have a look at this or directory go to the full article.

Greetings.

 

[ealltech]

Have you looking for an economic solution for having low latency audio i/o with a single board computer linux, such as Raspberry Pi 2, BeagleBone Black, or Graperain Quad.?
Suggests they got a Turtle Beach Amigo II to have acceptable ~5ms latency. I don't think it's impossible. 100ms is waaaay too high for my purposes. But I can't imagine a BBB doing that much worse than my dinosaur computer. And I'm at hardly perceptible levels of latency. Anyone else have experience with guitarix and SBC's? I'd think most of the newer quad cores would handle it just fine. Especially if I strip down the OS. I might even run the GUI from a separate computer.