that is what the SSP is - it’s an optimized realtime linux audio system. We ship it with our own sound synthesis software but you can disable that software, and put other linux audio software on it as well and even attach a mouse and keyboard and run a desktop manager if you wanted to.
again, that is what the SSP is all of what you describe is already possible and already provided with the SSP. Regarding VST support, you can only host linux/ARM VST plugins in our software, you cannot use Mac or Windows VST plugins.
I recommend you listen to the interview I did with Darwin Grosse a while back -
Like I said in the above interview - Yes, you can build your own linux audio system, using whatever processor or motherboard you want, ARM or not.
The point is that it is a LOT of work if you want to develop something like the SSP. We are not using a raspberry pi or any other off the shelf SBC. The SSP has a custom carrier board with all the analogue I/O on it, USB, clocks, power supplies, audio converters, input and output stages etc…
To do it right and get the performance and quality you want, you have to design your own electronics from the ground up. The Pi and other SBCs are development tools, not professional end user products.
When you are done with the hardware, then you have to fix all software and driver related problems, develop custom drivers, optimize and test the kernel, and then after that put your application software on it and make that work well with your platform.
I don’t want to discourage you, just giving you some insight into what goes into this. If you take all the work that went into it into account the SSP is really good value for money.
Whether or not you have low latency on a bare metal system with an M4 CPU depends on how your wrote your software and how you interfaced your DACs and ADCs and how you move data from the converters into and out of your CPU.
If you build a linux system you can achieve extremely low latency as well, you have access to the kernel and driver source code and there is a lot of info available on how to achieve this.
That is what we did for the SSP by the way, we are at around 3ms latency at the moment, and we plan to further optimize this as we go forward with software updates.