OctaMed sound studio

[bloodline]

I'm with Karlos here, the base rate is set by the video refresh rate (edit: from memory 28khz), the playback frequency is based on a period between fetching the next sample
Paula doesn't play back at quite the right frequency, I won't be able to emulate that as I don't plan to write a whole bloody tracker!

[nicholas]

I'm with Karlos here, the base rate is set by the video refresh rate (edit: from memory 28khz), the playback frequency is based on a period between fetching the next sample
Paula doesn't play back at quite the right frequency, I won't be able to emulate that as I don't plan to write a whole bloody tracker!

Writing a VST based on this used to be on my list of things I'd like to get around to one day.

http://zakalwe.fi/uade/

[minator]

I think it's a bit different. IIRC, and I might be wrong about this, it isn't that it plays samples at different rates (ie, higher values for faster rates), but instead uses a sample period (physical duration between sample changes) to define the playback speed. This is a reciprocal quantity with respect to frequency - hence lower period values result in faster playback and vice versa. I'm a bit hazy on the details now but I seem to recall that these periods are expressed in a "ticks" of a clock that's derived from the system clock and runs at around 3.5MHz.

Well, that's what I mean. Your description is the technical description of how it actually works.  But the end result is the samples are not played at a fixed frequency.

This means that arbitrary playback rates aren't possible - the "tuning" of higher notes gradually becomes less precise than lower ones since the period value becomes smaller (thus having fewer bits of precision).

There have to be some interesting slew and phase effects resulting from this method of playback that are hard to reproduce in a conventional mixer.

Yup.

It also means (non-smoothed) mixer based playback will also have errors, just different ones.