Does a lack of processing power affect the "Final Summing Process?" (Bouncing)

[BadgerS88]

Does a lack of processing power affect the "Final Summing Process?" (Bouncing)

As the title reads...

Already, all over the internet and and worldwide even, there has been a debate over the quality or loss of quality of summing all your tracks together. As we all know, there are limitations of processing power when it comes to DAWs. Even to ProTools High Density. You can always rack up more DSPs and proccesors to help deal with the work load but there will always be a limitation somewhere.

My problem is, Ive only got a Mac G5 with 2 96DSPs and running ProTools HD. Anyways my question is;

If you are running out of processing power, due to the fact your running too many processor hungry plugins, affect the quality of the final summing process or the track?

Theres already be scepticism about summing qualities alone, but would lack of processing power in DAWs worsen the situation?

Could anyone shed some light on this situation, and please if you could, give me an example, comparison, or cite your references if any. Thanks a bunch.

 

[Cheez]

There are a few factors in play. If you are dealing with many tracks, the HD speed also comes into play. But I believe in general, bouncing digitally does not lower the "quality" of the mix. It all depends what you mean "quality". The obvious time during mix-down when "quality" will be compromised is during dithering (when you go from 24 bit to 16 bit, for example). So it's recommended to dither only in the final step.

If you have many tracks and your HD is not fast enough, you will usually encounter pops and clicks in the track. So, it's recommended that the HD you are using for recording the final mix and the one for processing are 2 different HDs, particularly if you have many tracks and working at 24bit.

If you have lots of plug-ins that drains your CPU, the "quality" (bit-rate wise) does not change. But you will encounter other problems that will affect your mix - pops and clicks etc. So you need to choose your plug-ins wisely. And you can use one plug-in for a few tracks instead of one plug-in for one track if the plug-in is the same. You can adjust the bus signal from each track to the plug-in. This will decrease the CPU usage. Otherwise, you'll need to bounce. Eg: use heavy effects on one track - bounce it. Then add on other tracks a few at a time. This way, your plug-ins are not being used all at the same time. Bouncing should affect the quality too much as it is digital.

Having said all this, I'm no sound engineer. All this comes from a musician's perspective (not a sound engineer's perspective) as I've recorded my own multiple sample tracks from beginning to mixdown over the years. People like blueprintstudio (the real expert) may have a different opinion, which I'll be glad to hear and learn!

Forgot - RAM also plays an important part in plug-ins.

 

[BadgerS88]

...

But theres also an article I've read up on the net, about DSPs cause, (to some degree) some phase cancellation, especially in the case of EQ plugs. Because EQs create many duplicates of the waveform in that certain frequency u chose to boost, and some of the waves there might cause some destructive wave interference.

Another question to anyone. Is there any professional comparison article online about Summing all your tracks Digitally through Protools HD or any other high end DAW, or summing your tracks through the same DAW but using the SSL onboard summer or compressor or any other summing boxes (eg NEVE boxes)

 

[sj2six]

Alternatively, once you have confirmed your plug-ins settings and wish to bounce it but is afraid the lack of processing power, Copy and Paste the settings of your real-time plug-ins (RTAS or TDM) to the non-real-time AudioSuite plug-ins and process all the tracks before bouncing.

 

[godchuanz]

Definitely a myth.
In the digital domain, the only possible cause for phasing problems will be plugins which work ONLY in real-time buffered mode. If you have a lack of CPU power, the plugin simply do not get allocated CPU resources as frequently. But it will not skip any audio frames or misbehave while it is "asleep".
What a plugin does is: it simply sleeps longer before operating on a piece of audio, the same piece of audio even on the latest high-end computer.
Unless, of course, the plugin is written to work ONLY in real-time mode, one which I have not yet seen.

Quality-wise, i.e. sampling rate and bit depth, that depends on the plugins, not the CPU. If your plugin is designed to dither and downsample every piece of audio it receives to 8-bit, 22050Hz, there is no use even if you have the best CPU.

So, in other words, there is almost most definitely no sound quality loss if you do not use the best CPU. The only drawback is... it takes a long time to finish the summing process.

 

[unsane]

theres a definate difference in outboard VS ITB summing..google abit theres a page with comparisons of different summing boxes/mixers with audio samples.

whether its phase issues or not i don't know, but for a laugh a few friends and i summed stems through a crap yamaha mixer VS a PT bounce taking into account levels and consistent pan laws and it sounded better. more "glued" and warm to use a few cliches. it was a rock mix though, i personally don't think the results would be as useful for say a metal mix, but it was a definate difference.

 

[ac]

Definitely summing in the DAW sounds different vs outboard gear. But it's going to be dependent on whether you like the results. Summing internally quality wise will depend on the number of tracks, bit depth, rate, pan laws, while externally the DA/AD conversion and every component in there is going to affect how it sounds.

Don't forget to use those plugs with linear phase.

 

[giri]

As the title reads...

My problem is, Ive only got a Mac G5 with 2 96DSPs and running ProTools HD. Anyways my question is;

Just to understand you better, do you mean that you have two 96 I/O interfaces or do u run HD2?

 

[BadgerS88]

Yup yup. My bad. I think you already know me giri. Its Fraser...

 

[blueprintstudios]

BadgerS88 : to answer your question through my experience, indeed there're limitations in everything. even if they say possibilities are limitless, but reality check, it's limited to hardware or the brain of the person operating the DAW. As a syntrillium cool edit user, i have to admit, I've barely hit the limit of the average DAW (sonar/cubase/ableton/protools)'s maximum capability. as all of you know, cool edit is pretty buggy indeed. and it's worse when you load multiple dynamic processors/tracks to make your mix sound nice. I got so much more ideas to try out while i'm young and creative still, but thats until I pick up using a more stable DAW like cubase / sonar. some of my friends say although my mixes sound good, but I've "over-exhausted" cool edit. made it do more than it was programmed to. etc. so meantime i'm my own worst enemy to limit myself.

and another experience, I've seen my friend who's a master on cubase, he's got a killer core2duo pc with 4 gig ram maxed out/terabyte hard disk and the killer of all a TC powercore + UAD DSP combination in the same PC. what could be the limitation you ask? to be honest, I don't think he's been limited in terms of creativity or pc hardware but what stops him right now is, he actually utilizes fully all 4gig ram and core2duo/UAD/TCpowercore processing with the insane amount of VSTs he use for his mixes. and at times WINDOWS XP still crashes on him. you get the idea now? you can't use Vista cos of potential incompatibility and he has to make do with windows XP. so until microsoft releases an OS that DAWs will run super stable on with abuse.

so to say via experience also, i don't know what you mean by "quality" but bouncing shouldn't affect quality in the digital side, at least not audible. maybe if you bounce 1000 - 10000 times. then yeah maybe. but like what the others say, make sure your PC/mac is powerful enough not to "choke" while bouncing otherwise you're gonna hear clicks/bumps/skips etc. if it sounds right, then "hearing is believing" ?

Cheez : hahah i'd appreciate if you call me "experienced" than "expert", pressure man. suddenly I gotta step up in my cents worth.

BadgerS88 again : phase cancellation via VSTs hmm.. through my experience, the VST (even hardware processors) that does this would probably be something like those sonic maximizer /izotope ozone exciters. I had an SPL Vitalizer MKII hardware rack last time. I vaguely read about what goes on in an "Audio Exciting" process... some of them use phase stuff, inversion or something. so if you're gonna EQ, just EQ, don't over-use exciters and if you got problems with that certain EQ VST that causes this phase problems... then either use that only or don't use lor. they were programmed to be use as "alone" , not in combinations.

as for your "professional comparison article online", nope. haven't come across one yet. you could email Sound On Sound to try ask them feature.

99¢ worth.

 

[Cancerous]

uhmm...

protools HD accel and core cards have their own processes for plugin's hence i dunn think it would be eating up your CPU power.

yes, no maybe?

 

[ac]

Have you played cool edit's hidden easter egg pong game?

in sonar i do notice some small differences if you bounce softsynth tracks first vs exporting everything in one go, in complicated projects.

It's always a compromise between the number of generations of bouncedown vs available computer power.

 

[blueprintstudios]

hah yes i have. but I'd rather be playing with my own balls if I had free time like that.

 

[ac]

as i'm sure most have

!!!

 

[giri]

BadgerS88
"My problem is, Ive only got a Mac G5 with 2 96DSPs and running ProTools HD. Anyways my question is;

If you are running out of processing power, due to the fact your running too many processor hungry plugins, affect the quality of the final summing process or the track?

Theres already be scepticism about summing qualities alone, but would lack of processing power in DAWs worsen the situation?"

Hi Frasier,

With regards to your questions, which were quite a few, I would hope to shed light on whether "whether cpu or DSP intensive sessions" produce any deviations in the final render.

So I did a little experiment with the system and these were the settings playback engine for the following experiment.

I just started a new session and rendered out a 1kHz sine tone for a very short duration of time. I used the bounce to disk function with the option to import the rendered file into the session. I have included the in the screen shot, the system usage window as well.

Then i tried to max out the DSPs on the HD1 by the following steps
1. Creating another track and inserting 5 "dsp intensive" plugs.
2. Then I duplicated this track many times so that till i am nearly using all the processing power available.

After which i bounced out the sine tone again and imported it back into the session for visual appraisal and comparison with the original waveform. If there were any changes, then it could could that due to the heavy load on the DSPs, the sine tone was rendered with undesirable effects. However, this was not true as you will see in the following scrren shot that both waveforms look identical.

Then I created some more tracks and loaded the CPU with RTAS plugs, and the results were the same.

Thus one can conclude that even with heavy CPU and DSP loads the output from ProTools remains consistent without any deviation. Hope this helps.

 

[blueprintstudios]

actually i wanna describe through one of my experiences somehow related to this thread.

lets say I have

01) Drums-Hihat
02) Drums-Left Crash
03) Drums-Snare
04) Drums-Kick
05) Drums-Left Tom
06) Drums-Right Tom
07) Drums-Floor Tom
08) Drums-Right Crash
09) Lead Guitar
10) Rhythm Guitar
11) Solo Guitar
12) Bass
13) Lead Vocals
14) Back Vocals

so usually I can choose either to process them seperately like the above
1) Track.wav > Compressors/EQ/Reverb etc
2) " " " "
3) "" "
and so on . into one stereo .wav master file.

but I realised if I were to lighten the mixdown process by lets say mixdown seperately with the VSTs processed in :
01 - 07) bounce to stereo a) Drums.wav
09 - 11) bounce to stereo b) Guitars.wav
12) bounce to stereo c) Bass.wav
13,14) bounce to d) Vocals.wav

then after that mixdown again with 0 adjustments, just pure "Stereo master mixdown" of abcd.wav

it sounds sorta different compared to the earlier individual tracks > stereo mixdown than individual tracks > group tracks > stereo mixdown.

i guess this boils down to audio engine of the DAW? does anyone has the same situation as me?

 

[unsane]

killer test giri...you could also put one of the tracks out of phase and see if they completely null,probably the best test to see if it's identical or not.

blueprint..you're using cool edit or audition right? i believe when you're doing a bounce to track in either program it adds dither by default..across multiple tracks it'll definately have an audible effect..

 

[blueprintstudios]

hmm i'm not sure, I do the whole mixing/mixdown in the whole 32bit environment, only before I finally hit the last limiter then I'll dither/downsample to 44.1khz/16bit. i'm comparing with the final dithered 44.1khz / 16bit.wav

 

[BadgerS88]

Thanx everyone for your time to explain to me. Thnx Giri expecially for the test. Cheers.........

 

[giri]

No problems. Here's a test by Digi comparing ITB(in the box i.e. using you comp) and OTB mixing.

http://www.digidesign.com/index.cfm?langid=100&navid=49&itemid=25669