TOPIC: A word of caution about chaining plug-ins

A word of caution about chaining plug-ins 3 years 8 months ago #12737

Since there are many here who are chaining together multiple plug-ins, I thought it might be worth pointing out a downside that occurs where oversampling is required.

The sample rate conversion process always requires a trade-off. Correct linear phase filtering to remove unwanted harmonics due to aliasing adds latency. S-GEAR uses special oversampling filters to reduce latency introduced during sample rate conversion, however, for the most natural sound it is preferable to avoid multiple sample rate conversion steps.

The ideal solution would be for the plug-in host to offer an oversampling step inside the insert loop and have the ability to switch-off oversampling in your plug-ins. That way could chain multiple non-linear effects within a single upsample/downsample step. I doubt this will ever happen.

Cheers,
Mike
The following user(s) said Thank You: Studiostriver
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A word of caution about chaining plug-ins 3 years 8 months ago #12741

Thanks for the heads-up, Mike!
mike wrote:

I doubt this will ever happen.

I suspect not. Though DAW developers must continually keep an edge on their competition, so maybe some day...

It's an advanced, under-the-hood feature from which people would definitely benefit but not realize it's happening, and that's tougher to get onto the to-do list. However, if we're to continually push the art then it should be addressed.
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A word of caution about chaining plug-ins 3 years 8 months ago #12743

Is something like this what your talking about?
www.cakewalk.com/Documentation?product=S...=NewFeatures.15.html
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A word of caution about chaining plug-ins 3 years 8 months ago #12744

clintmartin wrote:

Is something like this what your talking about?
www.cakewalk.com/Documentation?product=S...=NewFeatures.15.html
That's very interesting. Probably Sonar are looking to provide some oversampling for the case where VST plug-ins don't do it but should! It would be more useful if they offered 4x and 8x options also.

Cheers,
Mike
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A word of caution about chaining plug-ins 3 years 8 months ago #12745

Thanks for pointing that out, Mike. From what I understand, down-sampling is the main offender – worse so in real-time. My only issue with the NCL 'Tube Driver' is it seems to roll off the highs at higher OS rates. It could just be eliminating irrelevant high harmonics. At least that's what I understand the purpose to be. I usually roll off the high end with the post LP filter anyway, so the high freq errors may not be heard. Seems DAWs could implement per channel OS rates to use for certain signal paths without using as much CPU as when applied to the whole project. Would S-Gear automatically not OS in that case?
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A word of caution about chaining plug-ins 3 years 8 months ago #12749

GCKelloch wrote:

From what I understand, down-sampling is the main offender – worse so in real-time.
For linear phase, both SRC processes require filtering with symmetrical coefficients before and after the current sample and it is this filtering which introduces latency. This is a real-time issue, for non-real time a DAW can re-align audio within a project.
GCKelloch wrote:

Seems DAWs could implement per channel OS rates to use for certain signal paths without using as much CPU as when applied to the whole project. Would S-Gear automatically not OS in that case?
S-GEAR does scale its oversampling ratio according to the current sample rate to achieve a processing rate of 8 x 44.1KHz. However, it doesn't currently expect to see greater than 96KHz base sample rate. So yes, if oversampling became a common feature in DAWs then S-GEAR could be modified to accommodate.
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A word of caution about chaining plug-ins 3 years 8 months ago #12755

Real-time linear phase filtering has been practically unusable for us. If compensated upon playback, yes, but for recording - for playing live - the latency kills the feel.

As a point of conversation, FabFilter's eqs use a mid-ground which they call Natural Phase. It's not entirely latency-free but nearly so, and although it still affects the punchiness of fast attacks and is noticeable with heavier slopes - like most eqs - it's very transparent and close enough to Linear Phase for rock 'n' roll.

When Linear is too slow, and zero latency eqing is too unpleasant, it's a good option. Maybe something to consider while DAWs play catch-up.
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