> - The website says: "With Elk hardware companies can move away from dedicated chips and use general purpose ARM and x86 CPUs without any compromise in terms of latency, performance and scalability". Is this intended as a ready-made OS for hardware synthesisers, or as a way to host VSTs on consumer SoCs?
Seems like both and more.
> is writing a bare-metal executive the most difficult or expensive aspect of engineering a synthesiser?
Likely being a big part of the expense, yes. Obviously the hardware parts being a big chunk of it too, programming the software side of things are also expensive and sometimes makes the product receive less updates in the future because programmers who did understand the platform left the company. See Octatrack as an example, where the code is so complicated it's unlikely to see any bigger features released to it now as the original programmer left the company.
Also, consider that many people have experience with general computing platforms while not having special expertise about particular chips, this solution on a general platform can help more people get started, learn more and maintain their own setups with skills that easily translate as well.
> Is real-time Linux not overkill for most synthesisers? From the outside looking in, it looks like it would add more overhead and complexity than solve problems
Probably, but probably not. Music making is more about having options available and use those in creative ways. Being able to use a general computing platform opens up more options than specially programmed OSes for particular instruments. Being able to revive old synths with new software would be wonderful.