KVR Audio

sublogic · Post by **sublogic** » Mon Nov 04, 2002 11:21 pm

I'll start with a disclaimer: I'm not dissing SynthEdit - I think its brilliant and I'm trying to learn how to do something that sounds good with it right now...

but...

It seems to me that SynthEdit synths require more CPU than equivalent natively-coded VSTis.

Just wondering what anyone else has noticed...

Maybe it's time for that CPU/MoBo upgrade

x_bruce · Post by **x_bruce** » Tue Nov 05, 2002 4:46 am

I've noticed this too although to be fair there are some native coded VSTis that use more CPU and are seemingly no better in quality, names withheld to reduce possible rage commentary.

It is possible to optimize and I'd imagine as the program matures and as users create new modules the CPU useage may slim down. SynthEdit is simply an incredible idea that is very young.

I think it was a fair question.

VitaminD · Post by **VitaminD** » Tue Nov 05, 2002 5:31 am

yes upgrade.. do it.. you'll make yourself a happy camper

but hmms ive recently made several synthedit monsters which far exceed what my cpu can keep up with... (athlon xp 2000+).. its not that hard.. add 20 oscillators, include a filterbank with a couple lfos- and HELLO CPU OVERLOAD..

however i think the main thing ive noticed is that lfo's really eat cpu in synthedit.. this has also been commented on in the SE Y!(yahoo!) group... but oh well.. its not that big of a thing (to me).. just something ive noticed.

as far as synthedit goes, i think the quality and ease of use far exceeds any of the cpu requirements...

BONES · Post by **BONES** » Tue Nov 05, 2002 8:31 am

You would have to expect that in a modular set-up where it is not always possible to be 100% efficient, as you might be able to achieve in a fully coded synth. That said, my two SE synths use about the same amount of CPU as WaspXT and they have roughly the same number of parameters.

LighthouseAtDawn · Post by **LighthouseAtDawn** » Tue Nov 05, 2002 9:04 am

Yes, building an algorithm from modules always adds a little
'overhead' to the CPU usage as you have to do a lot of
non-audio stuff that you do not need to do when you code
the whole signal path from start to end in one function.

Also, certain assumptions and optimizations cannot be done if you
don't know how the signal flow will look like when coding.

There's not much you can do about this. The only thing the "professional"
commercial modulars are doing to reduce CPU usage are

a) programming all modules in assembler using processor specific
SIMD (single instruction, multiple data) extensions, such as MMX,
SSE or AltiVec.

b) reducing the 'internal' sample-rate (for example running 22KHz when
the output is at 44.1KHz and then upsampling, which is still way faster
than doing everything in 44.1KHz...)

Both methods significantly can speed up the synth, at the cost of being
a huge amount of tedious work and making the program non-portable
in the case of a), especially a lot of work, if you want to support multiple
platforms.

And at the cost of sound quality, tending to sound 'thin', 'flat' and less
bright in the case of b).

I've also begun writing a modular synth some time ago, but now that
there's synth-edit and VAZ and all these other freeware or shareware
modulars, I guess there's no real need to continue on this.

Some of the synth-edit generated VSTi's seem very good and useful,
however, I fear with a 'save as VSTi' function, the risk is high that we'll
all be flooded with shitloads of primitive and useless VSTi's in the future...

Best,
Lighthouse

sublogic · Post by **sublogic** » Tue Nov 05, 2002 9:18 am

Thanks all for the interesting replies.

-sub-

pHz · Post by **pHz** » Tue Nov 05, 2002 5:17 pm

[lighthouse] Some of the synth-edit generated VSTi's seem very good and useful, however, I fear with a 'save as VSTi' function, the risk is high that we'll all be flooded with shitloads of primitive and useless VSTi's in the future ...

.. have you read your own signature

... cheers

rob

Collusion · Post by **Collusion** » Tue Nov 05, 2002 5:41 pm

For what it's worth, SynthEdit's CPU optimisation is an area that Jeff's working on currently.

think the main thing ive noticed is that lfo's really eat cpu in synthedit

There's a reason for this - SynthEdit LFOs are really just standard oscillators producing sub-audible frequencies. As a result of them being standard oscillators, they operate at "audio rate" (eg. 44.1kHz), when they really should be operating at "control rate" (probably half, or quarter, of the "audio rate") and are also anti-aliased, which is probably not necessary for LFOs. Hence the high CPU usage.

Jeff's looking into creating a dedicated LFO module, which operates at "control rate".

Collusion · Post by **Collusion** » Tue Nov 05, 2002 5:58 pm

Quick tip (sorry if you know about this one already) :

try using Level Adjuster modules instead of VCA modules - they use a lot less CPU.....

SynthEdit synths... higher CPU usage?