Access Virus C on Zynthian (DSP 56300 emulator)

[This thread is a follow-up from
RPi5 specs and review - #25 by Aethermind, courtesy of @Nicolaz and @jofemodo ]

Update on the Motorola DSP 56300 emulator, for the Access Virus C plugin (called Osirus):

The generous developers community’s website provides the software instrument also as a Linux Arm64 (aarch64) package, either in VST2, VST3 or CLAP format.

To my limited understanding, using Osirus in Zynthian should just require a VST Linux wrapper, and as soon as ZynthianOS switches to aarch64 it might be possible to exploit the RPi5 improved CPU performance, to sustain the required DSP 56300 duty-cycle (136 MIPs for the Virus C implementation - for a comparison, the test console provided by the developers returned 460 MIPs on my i7 quad-core iMac).

As for the Access proprietary synthesis program, I quickly traced a third-party open repository with both the Virus B and C ROM (reverse-engineered?) software, that the 56300 emulator site cannot provide for obvious copyright infringement reasons:

Today I have had a try at Osirus on Cubase/Mac, and - my goodness - it simply sounded phenomenal, going straight away in the top region of my preferred software instruments, be them freeware/open source or commercial.

I think that embedding Osirus in a future stable release of ZynthianOS would greatly improve the synthesisers armoury of this project, complementing the features of the local Swiss army knife Zynaddsubfx quite perfectly.


It’s a nice thought, but I’m not holding my breath; at the end of this thread Access Virus emulator on Zynthian? - #5 by JayBee it was concluded that the RPi4 is probably too slow even if the emulator can be improved and the Pi overclocked.

Indeed, as a (very) loose MIPS comparison, a while ago, I tried running the test application that the Osiris team brought out on a ten year old laptop (i5-2450M), which is about as powerful in terms of CPU power as the RPi4, and as I recall it didn’t even managed to run the Virus B successfully.

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I certainly wouldn’t recommend holding your breath - we’re talking about many months, perhaps even years to complete the transition, but between the improvement due to switching to 64 bit, multiplied by the improvement between RPi4 and RPi5, I think we have a good shot at getting enough CPU power to run either all or some of the Access Virus versions via the DSP 56300 emulator. And if not, well, there’s always RPi6 or maybe RISC-V! GodSpeed Zynthian!

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Godspeed You! Black Synthetor (of a Zynth V6).

Pun for the off-stream connoisseurs intended!

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