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IraSeigel
10-06-2008, 09:38 PM
Is it true that all convolution reverbs introduce latency and are thus unusable in SAC? And specifically regarding using Altiverb in SAC?

Thanks,
Ira

Trackzilla
10-06-2008, 11:04 PM
all of them I know of do...I remember reading somewhere about a 'latency compensator plug' to allow convolution reverbs or other fixed latency plugs to be used with non-latency tolerant apps...wonder if such might be of use here?

Bob L
10-06-2008, 11:37 PM
Most likely not... even if the latency plug returns zero filled buffers to allow the main engine to continue running, the plugin data will be returned with latency and mixed into the main signal late and out of phase.

Now... in the case of reverb... that will not necessarily be all bad and will end up sounding like a pre-delay reverb setting... but with other plugs, the result could be less than desirable.

Bob L

IraSeigel
10-07-2008, 12:41 AM
Most likely not... even if the latency plug returns zero filled buffers to allow the main engine to continue running, the plugin data will be returned with latency and mixed into the main signal late and out of phase.

Now... in the case of reverb... that will not necessarily be all bad and will end up sounding like a pre-delay reverb setting... but with other plugs, the result could be less than desirable.

Bob L

So, I'm not understanding. I thought that if SAC sensed a latency-inducing plug, it would simply refuse to let it operate (sorry for my bad terminology). Is that not the case?

Ira

DominicPerry
10-07-2008, 02:30 AM
IIRC, SIR2 has a 'non-latency' mode, although it's heavy on CPU.

If SAC detects a latency-causing plugin, the plug-in gets bypassed.

Dominic

Bob L
10-07-2008, 07:36 AM
Yes... it will bypass a plugin that witholds buffers... that means if the sent buffer size returns smaller or larger, the plug is detected as latency causing...

But... some of these plugs will return blank buffers of the same size as they absorb data witholding the data for processing... in this case, SAC can not detect the problem and will continue... but the plugin will still cause problems because the data stream has been delayed.

I wish it were simple... but the idea of latency causing plugs has been a nightmare and continues to be no matter how you look at it.

My levelizer peaklimit function alters buffer sizes at zero cross boundaries but causes no latency in the data stream returned... but still cannot be used in the SAC engine because of the varying buffer sizes returned. Only the peaklimit function does this, so the Levelizer can still be used in comp and gate modes... and a comp with infinite ratio is pretty close to a standard peaklimit function.

Bob L

Naturally Digital
10-07-2008, 11:41 AM
I thought SIR2 and Voxengo Pristine Space were both no latency convolution plugs.