audio stops when switching sub sessions

[krraqk]

Some more questions trying to solve all my doubts about Cantabile prior to make the switch to it...

The problem is that when I switch sub sessions (via program change sent via midi with my FCB1010) the "load percentage" (cantabile cpu meter) shows a big spike, something like 250% +- and then the audio stops for a second (aprox).

The sub sessions are one of the most important features of Cantabile to be able to play live and switch between sounds! So it cant stop the audio signal or the function would not be useful.

Is that behaviour normal or its related to my system in some way??

Im using asio4all (because its better and more stable than the native drivers of my card) and Im using a 192 samples buffer (I need looow latency in order to play without a noticeable delay). When this halt occurs the normal asio4all icon (a green arrow) shows momentarily a red "double bar", which is indicative that the driver is overloaded or something, after that the "gren arrow" icon returns and also the audio.

The sub sessions consist in changing the suspend state of the plugins in several racks. Im using mainly NI, spectrasonics and camel audio vstis. Also to note that I have activated all the attributes in the sub session behaviour, otherwise the patches and sounds in the vstis would not change.

I need that feature to perform flawlessly while Im playing, so please what I can do to solve it?

[TiUser]

Switching sounds seamless is a kind of "art" even with subsessions.

Some plugins need time to wake up from being suspended. In this case it's better to bypass them if timing load allows this.

As far as I see you preferred plugins are samplers - I have given up trying to get seamless sound switching with samplers... when these start loading new samples you are lost.

Maybe I could need some good advice myself...

[krraqk]

Switching sounds seamless is a kind of "art" even with subsessions.

Some plugins need time to wake up from being suspended. In this case it's better to bypass them if timing load allows this.

As far as I see you preferred plugins are samplers - I have given up trying to get seamless sound switching with samplers... when these start loading new samples you are lost.

Maybe I could need some good advice myself...

I used suspend in order to avoid the cpu comsumption while they are idle, but maybe I have enough power to try the bypass option. But you mention "if timing load allows this", you mean that with the bypass it takes more time to switch than with suspend? I would have thought Otherwise.

Well although some of my vstis are sample based, in the small testing that Im doing nothing is loading samples while switching (im testing only 3 program changes for now and those are between the vstis that are synth based), so I think thats not the problem.

Maybe the problem is the metod Cantabile uses to do that switching, I would not care if that takes a bit more time, but what I cant allow is big spikes and audio interruptions. Being an important feature im surprissed there is not much talk about it in this forum, maybe its my system or plugins, the fact is that I need to clarify and solve this prior to purchasing and using Cantabile.

I will keep testing...

Thanks another time

[TiUser]

If you suspend a plugin it is not ideling, it is switched off - like a switched off HW rack module. You are right, this is to save cpu - but it can have it's tradeoffs... I have a synth plugin too I know for sure it needs some time to wake up, it's like a hickup until it is ready again, it's not instant. Many plugins wake up so fast that you won't notice but some plugins do not wake up as fast as you wish.

BTW, Cantabile is the only host I know about that can suspend plugins that way at all. Would be interested if anyone knows other hosts offering this. I think most do more likely bypass as standard procedure to mute a plugin.

In Cantabile just bypassed plugins are still running - like a switched on HW rack module - only being cut off from midi input and therefore not producing sound. If the plugin processes audio input, that is muted also. Having said that if you switch to a new session bypassing a plugin also means it sustains naturally - at least if you do not change the sound patch too - then it's up to the plugin again what happens... (at this point I have suggested a "plugin double buffering" strategy but that has not been implemented yet... would mean loading a plugin twice so that the last sound can sustain while the new is selected on the second, hidden plugin) ...cut off is still one of the better behavior... a big rumble another and again I also have another synth plugin that reacts in that way...

I am not really pleased about all that too, but it's not Cantabiles fault which offers more detailed options handling these problems than other hosts I know about.

Anyway and for short there are two basic options: you can suspend plugins with the benefit saving cpu but you can have trouble with "wake up". You can bypass instead for the price of higher cpu load. I would recommend bypass if your cpu can handle that and you need the most instant reactions.

Finally a pc with Cantabile does still not behave like a good live hw instrument. That seems to be an inherent disadvantage of the current VST technology and implementation as there seem no behavior specifications addressing these live issues... Usually you load up all your VST's in a DAW but you do not switch around sounds and effect programs or suspending them while running the sequencer, right? VSTs are studio technology even if many people try using it live...

But even some of the HW stuff have shortcomings when it comes to seamless sound changes. Only way to find out is to check out and have a critical view / ear on that... even if sound changes seem to work, try patches with different effects and you'll find even more devices that create trouble when you use changes without care... because effects are most of the time not part of the sound but mixer like inserted...

It's at the end all a resource and design question... and yet still a tricky business. Unfortunately you do not get seamless instant operation automatically - something I myself vote and cry for for years! But most makers do not care, everybody seems just listening to "perfection" of sounds, seemingly willing to accept anything (one killer is ridiculous loading times)... still overlooking the very basic stuff a performer expects and needs.

Apologize the long post - but that's how I feel about all that pc+software as music workstation... too much work - too few music...

[krraqk]

Wow, that a very detailed and explanatory reply, many thanks for your time and effort.

I will try to switch all the plugins to disable and not to suspend to see if it helps the problem.

Apologize the long post - but that's how I feel about all that pc+software as music workstation... too much work - too few music...

Thats exactly how I feel about it.

[TiUser]

...if you have a special sequence you can also do a two step strategy, first bypass/mute, second suspend... that's the odd tricks I was talking about.

Some way strange that VST technology assumes endless cpu power - I see nothing managing real resources like old synths already could do 25 years ago, like voice stealing...

PC's running windows seem not presenting real resources, just everything is virtual here and there... and the only real solution on some overload is crackle...