DSP assignments and usage - PCI

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Music Manic
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DSP assignments and usage - PCI

Post by Music Manic »

How does Scope assign devices to DSPs? Is it random or is there any special protocol?
I know that DSPs can be assigned to devices in the SDK and I wondered why this was never addressed in the program
Seeing that phase issues are inherently there. The STM mixers can assign channels to boards and has phase compensation available but can’t this be extended to individual devices? I’ve imported two mono devices to check if the Left and Right channels are phase coherent and there’s usually a two sample delay which is obviously caused by the DSP assignment.

In the DSP view page, how can you tell what’s assigned where? There is just Sync and Async information there so it’s hard to see what’s going on.
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garyb
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Re: DSP assignments and usage - PCI

Post by garyb »

sync is dsp usage.
async are dsp processes that use native resources.
the dsp number is displayed first.

as a user, you aren't really supposed to know the details, but you can see what happens when you load things.
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astroman
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Re: DSP assignments and usage - PCI

Post by astroman »

DSP assignement is done by an algorithm that tries to distribute things as efficient as possible.
A developer can (and has to ) take care that certain parts of the code aren‘t spread over DSP boundaries or otherwise compensate the sample offset.
That’s what the STM mixer does - only in early days this was sometimes overlooked (f.e. some Sonic Timeworks devices).

A moderately complex project may introduce a couple of „unintended“ offsets randomly as a tradeoff for much higher resource efficiency. UAD and Pro Tools systems are way more restrictive in this very context.
(but their architecture is quite different from Scope)

This topic was discussed years ago and it‘s counting peas (imho) because the offsets are fixed during project runtime, not floating around.
It‘s pointless to tune a mix to 2 samples precision because the difference is probably in the range of a plain wall versus a wall with a TV mounted to it... or the natural change in air pressure from day to day ;)
Music Manic
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Re: DSP assignments and usage - PCI

Post by Music Manic »

astroman wrote: Tue Mar 02, 2021 7:31 pm That’s what the STM mixer does - only in early days this was sometimes overlooked (f.e. some Sonic Timeworks devices).

Ah I use the sonic timeworks master compressor still. Are the outputs not phase coherent? What problems do other sonic timeworks devices have?

I’m not splitting hairs. I’m just trying to understand what’s going on under the hood and still like using scope’s devices.

P.S. why are the ASIO drivers not released when a DAW crashes? You have to reboot Scope for the drivers to be available.
Music Manic
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Re: DSP assignments and usage - PCI

Post by Music Manic »

garyb wrote: Tue Mar 02, 2021 5:23 pm sync is dsp usage.
async are dsp processes that use native resources.
the dsp number is displayed first.

as a user, you aren't really supposed to know the details, but you can see what happens when you load things.
Ye I’ve noticed things get spread all over the place. I’ll try with just a singular device to see what happens.
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astroman
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Re: DSP assignments and usage - PCI

Post by astroman »

The Sonic Timeworks Master comp isn‘t affected by this flaw, it‘s a later device... or was tuned properly.
I used it frequently back then, but later turned to the SAW Studio Levelizer for final loudness.
(I‘m not pushing things too hard anyway - Levelizer is comparable to FabFilters Pro-L2, but more simple to handle)
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valis
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Re: DSP assignments and usage - PCI

Post by valis »

This was a severe problem in the 2.x and 3.0.0 era, many of our driver & dsp related issues of this started to be fixed around the time of 3.01 and 3.01c and progressed up to 4.5, at least in terms of the phase concerns and certain async issues (multiple CPU's aka multicore as well wouldn't work before 3.01c).
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Re: DSP assignments and usage - PCI

Post by Music Manic »

Thanks for the info guys.
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