Chipsounds too CPU heavy (in Ableton Live)

[rutgermuller]

Running more than 4 or 5 (single synth layer, reverb off!) instances is almost impossible because of a too high CPU usage. Anyone else experiencing this?

Hardware Overview:

Model Name: MacBook
Model Identifier: MacBook5,2
Processor Name: Intel Core 2 Duo
Processor Speed: 2 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 3 MB
Memory: 4 GB
Bus Speed: 1.07 GHz
Boot ROM Version: MB52.0088.B05
SMC Version (system): 1.38f5

running Ableton Live 8.1.3 with some simple Live plugins, which hardly take up 2% CPU.

[davidv]

Hi

First you can run 8 chips in one instance, so i wonder why you are using 5 instances for 5 sounds, this is really not efficient.
But even then you should not get taxed like this. Let us investigate a little

[davidv]

Heres my test, and what I assume is right according to the precise audio calculations im doing in DSP for chipsounds:

Mac Book Pro (first generation) Core Duo 1.87Ghz
SampleRate:44100
Buffersize:256
platform OSX 10.4 and WIndows XP (relatively same results +- 1% cpu)

Bidule: Running 6 stereo instances of chipsounds each with one monophonic instrument loaded:
CPU usage (one core): 28%

Bidule: Running 1 stereo instance of chipsounds each with 6 monophonic instrument loaded:
CPU usage (one core): 21% (you see you do gain by not wasting cycles in sending different mixes to the host)

Now of course if I raise the polyphony usage to 16 in each instrumentand play lots of voices, then yes
I reach the 50%+ CPU usage (one core) in both cases, but that is to be expected.

Please dont compare chipsounds with a "simple synth". it might be "square wavs" but they are
non trivial to get right without aliasing, it requires juice:
Each voice is *oversampled*, and all their envelopes and LFOs are as well.

Now i dont know if you have a Live session that you can PM me for more analysis, but these are the figures
which i think are normal.

[rutgermuller]

Hi David, thanks for the quick and comprehensive reply.

I wonder how I can easily use presets when I use one instance, that's one reason why I steered away from it. The other is that I have for example used 8 Kontakt instances running classical instruments and have never had any CPU problems. That's why I probably became a bit lazy about these things.

I'll try to send you my set soon, hope that will clear some things up!

[seb@plogue]

The other is that I have for example used 8 Kontakt instances running classical instruments and have never had any CPU problem

These are samples read from disk/RAM, in the case of chipsounds beside a few specific patches, sounds are always generated in realtime with oversampling.

[rutgermuller]

Ok, that's clear to me now.

But how come chipsounds even uses so much CPU when it's not playing!?

Here's a set of instruments I'm using in a track (I removed all the midi data) Even when not playing it uses 105% CPU in my case.

http://www.rutgermuller.nl/temp/chipsou ... estset.als

I would be very thankful if you could show me away to organize this in a more efficient way. So far I've found so much inspiration in chipsounds but in the end always got frustrated a bit and couldn't complete things.

[seb@plogue]

But how come chipsounds even uses so much CPU when it's not playing!?

Here's a set of instruments I'm using in a track (I removed all the midi data) Even when not playing it uses 105% CPU in my case.

Definitely not the expected behaviour, we'll try to reproduce with the file you have provided.

[davidv]

oh BOY.

live seems to use the 32 outs version of chipsounds by default. So right now it mixes 6x32 stereo busses for nothing.

[rutgermuller]

So I should go into settings and turn Inst. Poly down to the polyphony I want? And in the expected behaviour Inst. Poly should match the sum of the polyphony settings in the chipsounds mixer tab?

[davidv]

Hi
sorry my last answer was a bit rushed.

Story: chipsounds AU comes in various configurations: from 1 stereo out to 16 stereo outs.
and for some reason Ableton Live takes the 16xstereo output version instead of the default 1xstereo.

UNder that scenario the ARIA engine end up mixing LOTS and LOTS of channels uselessly (32*6=196 to be exact).

So there is no quickfix for this we will have to investigate how to have live run the stereo output only version.
and yes, in that case i have to admit that ill have to look at making my mixing code more efficient.

Ill post our findings tomorrow.

[pascal]

In the meantime, you can use chipsounds VST which has only two outputs (a stereo pair).
Don't use chipsounds Multi VST which has also 32 ouputs.

[rutgermuller]

THANKS! I'll try that.

What's the difference in using AU and VST anyway?

[WEAPONS OMD]

Nothing specific to add. however im an ableton user with almost the same mac set up, and ive run into some of the same problems trying to use chipsounds. i thought i was going nuts haha. this was very helpful and im looking forward to the results of your research. also, i have a question about audio set up. but it will be more appropriate to post a new thread...

[davidv]

What's the difference in using AU and VST anyway?

They are nearly identical, the difference resides in political preferences between hosts.

[davidv]

What's the difference in using AU and VST anyway?

They are nearly identical, the difference resides in political preferences between hosts.

People experiencing this issue on mac should get the following:

http://aria-public.s3.amazonaws.com/ARIA_1.0.9.8_Update.pkg.zip