Phil!!! I've got crackle issues!!!

[mhuxtable]

Ok so this may be longwinded but I want to set the scene so I can get some good help.

 

I'm recording a song that is very layered in Cubase Studio 4. With all the layers and pluggins going, I have a bit of crackle. I think it's just from the CPU pushing too hard but it's not too distracting for me to mix. (i have experience overloaded CPU crackle before). I do have a very nice computer, but this song is quite intense. I recorded at 96k 24 bit.

 

I bounced the mix down to a stereo wave file, 44.1k/16bit. I opened it in WaveLab to "master". A very slight bit of crackle was on the wav file so the first plugin I used was XCrackle. That solved that issue. I then proceeded to EQ, Compress, and Limit & set the dither etc.

 

When I rendered the new file the crackle was out of control all over the place. XCrackle couldn't tame it. It was just trashed.

 

What did I do wrong? How can I save my mix? I'm about to try to convert the original Cubase session to 44.1 first & see if that helps.

 

heeeeelp

 

m

[davesacre]

Have you tried freezing some of your tracks, particularly the ones with the most demanding plugins? It's been a while since I've used Cubase, but I believe you can still do some mixing functions on a frozen track. It makes the process take a little longer, since you have to unfreeze a track to tweak the plugins and then freeze the track again.

 

Also, when you bounce, are you doing a realtime bounce or offline bounce? I believe a realtime bounce will have the same crackle as just playing the project with all the plugins running. An offline bounce may be slower in your case, but I think it will avoid any of the crackle since it takes just as long as it needs to process everything.

 

If you're still receiving crackle after this, I would wonder if a particular plugin is introducing it.

[Phil O'Keefe]

^^^ That's good advice.

 

If the CPU is overloaded, and you have already maxed out your buffer size, and you've turned off anything and everything in terms of un-needed software apps to conserve CPU horsepower, and you're still having issues, it's time to start considering "rendering" some of your plugins.

 

I use Pro Tools, which currently doesn't have a "freeze" function, so my methodology might not be as efficient as what is available to you in Cubase, but the basic idea is the same - you want to "apply" your plug in processing to a new copy of each track's audio file so that you can turn around and disable those plugins from the tracks to conserve / free up CPU resources. You may only need to do this for a few of the tracks to reclaim enough CPU power to avoid the crackling issues... I recommend starting with tracks that have lots of plugins on them; especially ones that are known CPU hogs. I also recommend "rendering" tracks that you know you're happy with and don't think you're going to want to make any further adjustments to.

 

Here's how I do it:

 

1. I disable (but don't remove) the plugins from several tracks - enough so that the CPU is running in its "comfort zone" and not in any danger of overloading. Your CPU usage meter in your DAW should be helpful here... but they don't always show actual "max use", so even if it says you have 20% CPU capability left, you might not...

 

2. I assign a pre-fader aux bus from a track and route it as an input source on a new track. In other words, I assign a track's pre-fader output as the input source for a entirely new track.

 

3. After making sure all the plugins for the "source" track are enabled, I record everything over on to the new track - thus creating a new audio file with the plug in processing "embedded" into it.

 

4. I then copy that newly created audio back over to a new playlist on the old source track and disable all of the original plugins. Or, you can copy and paste any automation data (fader, aux sends, panning, etc.) over on to the newly recorded track and completely disable the source track (and all of its plugins) instead.

 

5. Repeat steps 2-4 for several other tracks.

 

6. Once finished, don't forget to re-enable the plugins for any "un-rendered" tracks. You may need to turn off a lot of stuff initially just so you don't have crackle issues while bouncing the tracks over, but once you've done a few (or several) tracks, and have disabled several plugins, you should be able to turn stuff back on for the remainder of the tracks without having any further crackle issues. If you've rendered several tracks, and disabled a bunch of CPU hungry plugins but STILL have issues, then your problems may lie elsewhere.

 

Using "freeze" (or following my suggestions) should seriously reduce the amount of "active" plugins you have running, but still leave you with the same "sound", because you have "applied" the plugins to the actual new WAV file recordings. If you need to adjust a parameter later, you can re-enable the source track and / or its disabled plugin(s), make the adjustments, then re-bounce just that track.

 

One last suggestion: If you're running any "VSTi" (virtual instrument) tracks, I'd start by "rendering" those first, since VSTi's tend to be fairly CPU intensive plugins.

 

Good luck, and please let me know how it turns out.

[Phil O'Keefe]

PS Converting a COPY of the session to 44.1kHz may indeed help - 96kHz requires a lot more CPU "juice" for plugin processing than 44.1kHz does, so assuming you were not too far over the system's limit in terms of CPU "horsepower" when running at 96kHz, in theory, you should be able to do all of the processing without any crackles (CPU overloads) at 44.1kHz, even without having to "render" anything; dropping the sample rate should cut the CPU requirements for plugin processing by roughly 50%.

[mhuxtable]

 

PS Converting a COPY of the session to 44.1kHz may indeed help - 96kHz requires a lot more CPU "juice" for plugin processing than 44.1kHz does, so assuming you were not too far over the system's limit in terms of CPU "horsepower" when running at 96kHz, in theory, you should be able to do all of the processing without any crackles (CPU overloads) at 44.1kHz, even without having to "render" anything; dropping the sample rate should cut the CPU requirements for plugin processing by roughly 50%.

 

 

thanks for all the advice you 2!

 

as you guys were giving me advice i tried this, and it worked! thank goodness. no more awful noise.

 

and after reading the other thread here, i'm recording 44.1/24bit from now on!

[WRGKMC]

One other item I didnt see mentioned. You may have tried it or it may be a moot issue at this point. You can increase your buffer size and latency to a much larger size and reduce that CPU noise. You only need small bufferes and latency if you're trying to process when recording with plugins. It bogs the controls down a bit, but it can work in many cases. i know I could do that with the older version of Cubase I have. I dont know about the newer versions though.

 

Also I found a trick quite accidentaly that works with minor crackle using that same Waves XCrackle plugin.

 

Set the threshold to max and the other slider to minimum. I couldnt tell you why it works that way. You would think you would need to push the second slider up so you hear a difference using extreme reduction but for some reason the plugin works in reverse when CPU distortion occurs. For other types of crackle it definately needs to be run the normal way, but there must be something different when CPU crackle occurs. Maybe the crackle isnt created by peaks and its inside the lower DB levels of the wave file.

 

I think it just has something to do with passing through the plugin that way, it fixes the crackle at lower db levels. The waveform is slightly reduced, but the noise will be gone. I just dont know why.

 

I occasionally get that crackle on some tracks when resources were low recording. I render the XCrackle and it completely removes the noise. I can blow the waveform up and view it before and after the application. I cant visually see the cause of the noise though and its always stumped me why it works. I'm just glad it does.

[mhuxtable]

 

One other item I didnt see mentioned. You may have tried it or it may be a moot issue at this point. You can increase your buffer size and latency to a much larger size and reduce that CPU noise. You only need small bufferes and latency if you're trying to process when recording with plugins. It bogs the controls down a bit, but it can work in many cases. i know I could do that with the older version of Cubase I have. I dont know about the newer versions though. Also I found a trick quite accidentaly that works with minor crackle using that same Waves XCrackle plugin. Set the threshold to max and the other slider to minimum. I couldnt tell you why it works that way. You would think you would need to push the second slider up so you hear a difference using extreme reduction but for some reason the plugin works in reverse when CPU distortion occurs. For other types of crackle it definately needs to be run the normal way, but there must be something different when CPU crackle occurs. Maybe the crackle isnt created by peaks and its inside the lower DB levels of the wave file. I think it just has something to do with passing through the plugin that way, it fixes the crackle at lower db levels. The waveform is slightly reduced, but the noise will be gone. I just dont know why. I occasionally get that crackle on some tracks when resources were low recording. I render the XCrackle and it completely removes the noise. I can blow the waveform up and view it before and after the application. I cant visually see the cause of the noise though and its always stumped me why it works. I'm just glad it does.

 

 

thanks dude! I forgot about the buffer & latency thing....i probalby could've done that. and i will for sure try that xcrackle trick next time i need it!

[Phil O'Keefe]

One other item I didnt see mentioned. You may have tried it or it may be a moot issue at this point. You can increase your buffer size and latency to a much larger size and reduce that CPU noise.

 

Pretty much the first thing I mentioned...

 

If the CPU is overloaded, and you have already maxed out your buffer size, and you've turned off anything and everything in terms of un-needed software apps to conserve CPU horsepower...

[WRGKMC]

One other item I didnt see mentioned. You may have tried it or it may be a moot issue at this point. You can increase your buffer size and latency to a much larger size and reduce that CPU noise. Pretty much the first thing I mentioned... If the CPU is overloaded, and you have already maxed out your buffer size, and you've turned off anything and everything in terms of un-needed software apps to conserve CPU horsepower...

 

Ah, I see it now. Sorry Phil. I must have read that with a different slant on what you were saying. Anyway, its a good thing to try and its something he didnt think of.

 

Steinberg can be a littel wacky with those settings. The Buffer size and latency settings were two different settings in the older version of Cubase 32 I used to use. You could do a hardware scan that locked in that stuff. If it dropped out you would have to go into audio options to change/overide the recomended settings. I never upgraded past the old Cubase 32 cause that stuff was glitchey with my setup. Those settings were always more stable with Cakewalk products like Sonar which I use now.

[Phil O'Keefe]

Ah, I see it now. Sorry Phil. I must have read that with a different slant on what you were saying. Anyway, its a good thing to try and its something he didnt think of.

 

Absolutely.

 

And it bears repeating: Use small buffers when tracking for less latency, and larger buffers when mixing for less CPU stress!