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CPU use shoots to 200% with onboard sound?


guitardood
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I'm build testing a OSX86 DAW.

 

No audio card and I tested with the built in sound chip.

 

It spikes to 200% when you use a soft synth.

 

IS that the lack of audio interface or crappy osx install?

 

Is my gear not good like mobo or something?

 

Was just a test but dang that was horrible!

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I'd love to see a CPU go above 100% utilization myself! :huh:

 

Can you tell us a little more like what soft synth, which host? Is this when playing a single note on the soft synth?

 

My CPU usage barely registers when using AU Instrutments in Logic Pro 7.2.3 so I do think you have some issues. For the most part I doubt its the built in audio as the CPU is usually the determining factor when using soft synths more than the audio device.

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As you're not very talkative about your setup ;) I give it another shot in the dark. In case you're on Cubase 4, I've read on their forums that high spikes could be normal with very CPU hungry plugs such as the Arturia or Izotope VST plugs. I didn't really understand all the tech details they were banging on about but as far as I understood this could be something not to be too worried about as long as PB and REC are smooth.

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yes a single note with Arturia and Live 5.1

 

I wont know untill I get the firewire audio from usps though what gives.

 

A single note,

 

So an audio card processes data for sound like a CPU? I was thinking the CPU was having to push the load and thats why I got 200% with a single key press!

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the CPU does all the calculations to make the sound for the soft synth while the audio cards takes the bytes and makes into a sound. Simple explanation but the audio card is not the issue in this case.

 

Is Live 5.1 Universal Binary? If not that might be the issue right there.

 

 

edit: I cant spells very good

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It seems you have a Core 2 Duo processor. Mac OSx86 doesn't handle 2 cores very well, so it may be necessary to disable one of the cores. You may be able to do this in the BIOS, but it is better to do it via command line. Before OS X boots up, you may have a place to put in boot options. If not, quickly press F8 before the OS X loading screen appears and in the boot options, type "cpus=1" but without the quotes. Then boot OS X and see it it worked. I it did, then add "cpus=1" to your com.apple.boot.plist file (or something like that) under kernal flags and it will start up without having to type that every time.

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It seems you have a Core 2 Duo processor. Mac OSx86 doesn't handle 2 cores very well, so it may be necessary to disable one of the cores. You may be able to do this in the BIOS, but it is better to do it via command line. Before OS X boots up, you may have a place to put in boot options. If not, quickly press F8 before the OS X loading screen appears and in the boot options, type "cpus=1" but without the quotes. Then boot OS X and see it it worked. I it did, then add "cpus=1" to your com.apple.boot.plist file (or something like that) under kernal flags and it will start up without having to type that every time.

 

 

Mac OS X 86 handles multiple CPUs very well. (Although Windows does have a slight advantage in some respects here). But still, it's the hacked kernels that have trouble with 2 CPUs. Partly because of the fact that there's more advanced hacking to do to get clean dual core support.

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Try setting project sample rate to 48 khz, it may cure this issue

Perhaps (and only perhaps) this may cure this issue but you're not doing yourself a favour in running a project at 48khz. For a pure audio project that is. For pro audio (in HipHop, R&B, Rock, Pop, Dance etc) you want to be ideally at 44.1khz/24bit. *If we're talking about DVD at 48khz/24bit, that's a different story but I don't think we are *

Dithering down the sample rate from 48 to 44.1 -which you'd have to do to get to CD format - will almost certainly induce artefacts like high freq aliasing, phase problems and other nasty stuff, no matter how good your gear, algorithms etc are. When running at 88.2 or even higher, the gain in high freq detail is already marginal in terms of listening pleasure for the average adult ear. The few exceptions where rates above 44.1 khz add an appreciable advantage mostly concern classical or certain acoustic Jazz joints, recorded on top class gear. That is, gear which would set you back at the value of a four bedroom house (at least)...

 

At 48khz you get all the disadvantages of sample rate conversion but only very tiny (basically negligible) advantages.

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Yes, it is rewarding running project at destination sample rate, but in this case, since all stock motherboard cards are clocked at 48khz, running at 44 will give undesirable penalty to processor. And since Logic (i just think guitargod is running logic) is doing all resampling in real time, problem may be even bigger.

 

But this subject is interesting. Lot of people claim that running at 48 and even higher sample rates do good for many aspects of sound. I must say all of it depends on gear, way of work and music you are doing, just as you pointed out. When working with lots of virtual instruments, personaly I don't see a point running them at high sample rates. But if you are, make shure that sample rate conversion and dithering are the last procesess you will do.

 

Lots of virtual instruments sound different on different sample rates. Specialy when they are running on samples, since the main rate is almost always 44 or 48k, and if you are running on different rates, there is always unecessary conversions.

 

And also, it all depends on your gear. If you don't have quality AD/DA and studio monitors, you will never hear much of the sound and little differences on different samplerates...

 

But main thing is: make music and be happy, don't think too much about technical aspect of it :(

 

Cheers

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But main thing is: make music and be happy, don't think too much about technical aspect of it :D

Yep, being happy with what you're doing always comes #1 :)

But hey, I can only be happy if my stuff sounds right :thumbsup_anim:

 

But seriously, you're basically stuck with the sampling rate you start your project with. If you're at 48 and need to add commercial samples of which the vast majority are sampled at 44.1, you'd have to upsample them first which already adds small artefacts and at mastering everything will have to be downsampled again...

I used to step into the same 48khz trap when I did my first digital recordings by hearing, at first, a little bit more air. But as I said, I've heard Apogee downsampled and dithered 48khz mixes through Weiss D/A conversion, did an A/B with a 'pure' 44.1 project and guess which one sounded WAY better...

 

BTW by all means, I would avoid sound cards that run natively at 48 only for music projects. Amateur sound cards in general for that matter.

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I think it was the UB version causing the issue. Ill have to try again.

 

How do you know if you have 2 cores and I can assume for audio its going to be noticeable with artifacts like pops?

 

Im off to uninstall and reinstall the UB versions.

 

thanks lots of info to soak up!

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But seriously, you're basically stuck with the sampling rate you start your project with.

 

You are completely right about that :thumbsup_anim:

 

I used to step into the same 48khz trap when I did my first digital recordings by hearing, at first, a little bit more air. But as I said, I've heard Apogee downsampled and dithered 48khz mixes through Weiss D/A conversion, did an A/B with a 'pure' 44.1 project and guess which one sounded WAY better...

 

Hm, you mean realtime resample and dither? I never used that, to be honest. There were always program for resampling in my case. For windows, I use r8 brain from voxengo, but I havent checked if there is something similar in OS X. Maybe this one http://www.lcscanada.com/audiomove/ but I haven't checked myself...

 

BTW by all means, I would avoid sound cards that run natively at 48 only for music projects. Amateur sound cards in general for that matter.

 

Yes, and you can get good sounding audio interface almost for nothing nowadays

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Yes, totally correct!

 

I uninstalled everything and installed UB live 5.2, and Native instruments UB (Both universal binaries)

 

Before I list this as a done deal in the hardware wiki,

how can I tell if I have dual core activated?

 

(In system profiler its showing two cores and one processor,.

 

Thanks cant believe how easy it was perhapse I just got lucky!!!

 

Also I used Xbench to test the laod on the machine but do you know anything a bit more down to earth like sysoft sandra?

 

NICE a $600 kick ass dual core audio rig that works as well as a $2500 G5? LOL

 

 

^_^

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