Bela: an Embedded Platform for Low-Latency Interactive Audio {via Kickstarter}

[ere2learn]

Just seen this on kickstarter,might be useful to some of you,I#ll be honest i'm not too familiar with this stuff

"Bela is an open-source embedded platform for real-time, ultra-low-latency audio and sensor processing on the BeagleBone Black."

https://www.kickstarter.com/projects/42 ... anks_tweet

[Mayae]

I was just looking at Raspberry pi for similar purposes. This looks very interesting in comparison.

[lorcan]

Yes, I saw this today too and backed it almost immediately.
They seem to have done an amazing job on the software side, using real-time kernel extensions and a custom driver, you can go down to as less as 8 samples buffer size !
Combined with the A/D D/A internal buffers (about 50 samples), that gives 1.3ms input-to-output latency @44.1k, which is quite amazing.
You can even go down to 2 samples process block size to shave off a few µs and get down to 1.02ms.
That's almost as good as a ProTools HCX system running at 96k, which is 0.7ms.

Also looking at a pdf describing the software internals, they report being able to run 700 wavetable oscillators @ 8smp buffer size, so I should imagine the Beagle Bone Black has plenty of processing power to run even the most complicated algorithms out there.
It can do convolution reverberation, has a Neon-accelerated FFT and math routines, etc.

Another nice feature is the analog control inputs run at 22kHz and are processed synchronously with the audio, which will allow very precise and fast gesture control, for example.
This would be great for 'cross-processing', ie using the control inputs as sidechains to control the main audio processing path.
Or you could connect piezos attached to drum shells and enjoy ultra-low latency that traditional MIDI modules cannot provide.

[Miles1981]

A guitar pedal with your own custom effects :p

[Ivan_C]

A guitar pedal with your own custom effects :p

[DaveHoskins]

With those digital inputs you could make a super responsive sample based drum kit!

[giulio_moro]

Hi,
I am one of the developers of Bela. Glad to see you are interested

With those digital inputs you could make a super responsive sample based drum kit!

DaveHoskins, I would recommend you use the 8 analog inputs for this, instead. You can easily hook up piezo pickups to the 8 analog inputs and these are sampled at 22.05kHz.
In case 8 inputs are not enough for your drumkit, one of the stretch goals of our camp aign (when/if we will reach 40k£) is to add additional analog inputs by multiplexing the existing inputs. This would allow, for instance, for 16 inputs at 11kHz or 32inputs at 5.5kHz, which should be more than enough!
Of course in all of these configurations the audio sampling rate would still be 44.1kHz.

A guitar pedal with your own custom effects :p

This is definitely one of the possible applications we have in mind. We are going to make a couple of new videos on this topic shortly, stay tuned.

Another nice feature is the analog control inputs run at 22kHz and are processed synchronously with the audio, which will allow very precise and fast gesture control, for example.

Well spotted. We also leveraged the high sampling rate for hybrid digital/analog feedback loops, as in the case of the Dbox hackable musical instrument https://www.youtube.com/watch?v=JOAO-EUtrGQ.
Also, their high sampling rate is useful for making vector graphics on an analog oscilloscope:https://www.youtube.com/watch?v=QKnh8dyCq-I

It can do convolution reverberation

Yes indeed, one of the students in our lab obtained almost 12 seconds of convolution reverb out of a stock Beaglebone with an audio cape. https://www.youtube.com/watch?v=0Ebnue1a4vc There should be margin for improvement with the new, optimized system.

I was just looking at Raspberry pi for similar purposes. This looks very interesting in comparison.

As far as we are aware there is no distribution available for the Pi which would give you hard-real time performance as Bela does. Inherently, all platforms that rely on the ALSA drivers for audio I/O cannot bypass the kernel as we do, that is also the reason why it is required to have a custom hardware for this purpose. Also, we are leveraging the PRU (an onboard real-time microcontroller) on the BeagleBone in order to talk to the audio codec and the ADC/DAC/Digital I/O

Thanks everyone for your interest, we are happy to answer any other questions and hear from you, either here or through our discussion group http://lists.bela.io/listinfo.cgi/discussion-bela.io
Also, check out out FAQs http://bela.io/faq.html

[Miles1981]

A guitar pedal with your own custom effects :p

This is definitely one of the possible applications we have in mind. We are going to make a couple of new videos on this topic shortly, stay tuned.

Great! as you can have synced params changes this would be tremendously efficient

[Mayae]

Hi, thanks for your involvement and answer. Maybe I just haven't seen it, but what's the current retail/launch-date? According to your kickstarter, you're pretty much ready to go? Maybe it's already possible to acquire it?

[giulio_moro]

Hi,
we already have working hardware designs and code which you can find online ( here are the cape schematics https://code.soundsoftware.ac.uk/projec ... lert/files ), but we will make some minor revisions to the hardware and software before the first public release. After the Kickstarter campaign finishes, the wait time will basically be as long as it takes to place orders at the factory, wait for them to be built and then ship them out.
Giulio

[thetechnobear]

congratulations @giulio_moro ... great to see you have already hit your first stretch goal

[DaveHoskins]

I presume it can go higher than 44.1Khz? Because that's so 30 years ago!
Most people master Stems at 48Khz+ these days.

[VariKusBrainZ]

I'm waiting for the final production version so all problems are quashed and any juicy changes will be available.

[Miles1981]

I presume it can go higher than 44.1Khz? Because that's so 30 years ago!
Most people master Stems at 48Khz+ these days.

Check on the page, it can do 2 channels at 88.2kHz on the non-audio parts, or 88.2kHz on the digital I/O, which is what is relevant when talking about stems (I'm not talking about mastering, because for CDs, mastering would be done at 44.1).

[DaveHoskins]

I'm used to doing film/video stems at 48Khz, and 24 bit.

Compact Discs? I remember those things. I can't remember when I last held one though.