The Official Sequential/Oberheim Forum

MODULAR => Dave Smith Modular => Topic started by: BobTheDog on May 02, 2018, 11:08:50 PM

Title: Bela Salt/Salt+
Post by: BobTheDog on May 02, 2018, 11:08:50 PM
Hi Guys,

I'm starting this thread to talk about the Bela Salt and Salt+ modules:

The Salt is a programmable module with 2 audio ins and 2 audio outs, 4 CVs ins and 4 CVs out, 2 trigger ins and 2 trigger outs, 4 knobs, 2 buttons and a USB device connection.

The Salt+ is an extender module that adds 4 CV in and 4CV out, 2 triggers in and 2 triggers out, 2 knobs and a USB host port.

I know there are already a few programable modules about so you may be asking what is so special about this one.

1. It has a decent processor, a AM3358 Sitara which is based on an ARM A8 running at 1Ghz with a NEON SIMD coprocessor, this is a nice processor for DSP. It also contains another coprocessor called the "Programmable Real-Time Unit Subsystem" or PRU for short, this is a 200Mhz microcontroller that communicates with the IO.

2. It has latency and jitter that are measured in microseconds not milliseconds even though it is running Linux. It manages this by use of a Hard Real Time kernel (Xenomai) which runs on top of the normal Linux kernel which it can preempt. The operating systems we all use (Windows, OS X, Linux etc) are not real time which is why they are so hopeless at audio, Bela is real time and when combined with the PRU can offer sub millisecond latency with maximum jitter of just 1 sample!

3. It has a built in Web Based IDE (via a USB cable) which includes an oscilloscope and spectrum analyser and Supports C/C++. PureData and Supercollider. You do not have to use this IDE, but for starting out it is pretty good.

I will add some more info when the modules arrive...

P.S. Anyone interested in the latency/jitter stuff here is a paper from the guys behind Bela:

Title: Re: Bela Salt/Salt+
Post by: chysn on May 03, 2018, 03:51:52 AM
Looking forward to it!
Title: Re: Bela Salt/Salt+
Post by: chysn on July 02, 2018, 09:52:22 AM
I read today that they only made 30 of these things. Salt seems like the kind of device for which a user community would achieve great things, but you'd need to get it into the hands of way more people.
Title: Re: Bela Salt/Salt+
Post by: BobTheDog on July 03, 2018, 12:47:30 PM
Yeah I was a bit surprised by that number as well. Hopefully they will do another larger batch.