Shruthi/Ambika compatible Sampler

After building both an Ambika and Shruthi, I have been thinking: What about a sampler compatible with Shruthi filter boards? If going that route it would be mono-/paraphonic, so maybe that’s not very fun to play? Plus would building it on an ATMega base make any sense, performance wise? STM32 would be the obvious choice, although if run monophonic, one could probably stream the sample directly from an SD card even on an ATMega.

If one builds a polyphonic Sampler, one Filter per voice would be required, thus it would result in a Ambika-like architecture. The voicecard hardware could maybe even be reused, by streaming the samples via SPI, although the bus would get very busy. The ATMega328s probably don’t have enough RAM to cache the samples when a patch is loaded.

Has anyone ever conveyed such a project, or would be interested in a monophonic samplers? I didn’t find any monophonic sampler besides the microgranny, probably for a reason…

Edit: for the Monophonic, Shruthi-ish device, i wouldn’t even change much. More or less just replacing the oscillators with a sample that gets played back, and maybe adding a DAC(+ADC) to have higher resolution.

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Interesting, thanks for the link!

I see this is monophonic and utilizes an ATMega2560? And an external SRAM chip, that’s clever, thus resulting in its 20s sample space.

Shruthis ATMega644 unfortunately doesn’t have that kind of memory bus. One could maybe squeeze the many pins needed for a parallel RAM into its gpio ports and then have on gpio bus left, but is that enough to control the rest of the device? Plus large enough parallel RAMs probably don’t exist as DIP (or would be huge if they did).

Edit: turns out they do exist:
one could maybe free one bus with an 8 bit latch between data and an address, so this could possibly work. But maybe an SPI RAM has enough performance already…

You’re kind of reinventing the WTPA.

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Another interesting device. Yes, feature-wise it looks similar to what I thought, although I was dreaming of a device in Shruthi form-factor, thus being able to use an additional filter(!) and all the mod-matrix goodness(!!).
I have been looking at other atmega-based devices and came to the conclusion that it is possible to play samples from an SD-Card in streaming mode in general.

As a note, I’m not really going after some profitable idea or something (I think the Shruthi-license wouldn’t allow it anyways), but just looking for a project to flex my embedded/dsp-ish muscles a bit. Or start building dsp muscles anyways.

Would a mega644 minus the oscillator code of the Shruthi-firmware still have enough processing power/buffer RAM to realise something like streaming samples and still be able to process the envelopes/lfos/modulations?