Crackling audio? Try CoreAudio Aggregate Devices.

[vigormusic]

My problem is when I play back after mixing and adding effects.

I am only using my firepod with this and only started to get the crackles last night after mixing for a while.

[valleysound]

Before Aggregate Device...
I have 2 Metric Halo 2882's. I set one as the master and the second as slave with WC in from the master, in DP. The lights on the boxes would show that they were locked, but not on the computer screen or vice versa. I got a lot of clicks and "skips" on the audio tracks. I managed to make it thru the session with the first track glitching the most, but repeated assigning of master and slave got the two boxes to behave, but the record log showed lots of dropped samples.
After Aggregate Device...
I got home and finally found the Aggregate Device settings. On my next date, there was not a problem at all. It also helped that there is a "Save Boot State" option on my Metric Halos. I occassionally have to reset the clock source and slave, but all the glitching is gone.

My buddy has a Motu box and his friend has another. He just plugs the two together and highlights both of them in the "Hardware Settings" and they behave for him. I told him about Aggregate Device, he'll try it next time even though he has no problems running two boxes separately.

[grimepoch]

When I went to 10.4.4 and above I had to use Aggregate, whereas before that 10.4.3 and below I believe I was able to just multiselect them in the panel. I run two motu 896s.

Also, MAKE SURE to set host multiplier to 2, this severely reduces CPU usage when running more than one interface (set the number to how many devices talk to the computer for audio at the same time).

Rick

[mizmo]

First of all, thanks to everyone that has contributed to this thread. It has obviously been a life saver for many users. Unlike many of you though, my use of an aggregate device did not rid me of my demons. However, much of the info you've provided has still resolved my crackling issue and I wanted to share how.

I'm running DP5.1, OS 10.4.7 on a G5 dual 2Ghz with 2.5GB RAM and a Mackie Onyx 400F interface (which frickin' rocks by the way). My crackling has been exactly as you all have described so I was bummed when the AD didn't help. However, based on some of your advice, I selected my Onyx 400F rather than an AD, and then set my Host Multiplier at 2 and my Work Priority at Low, and WA-LA! Crackling is gone. I have a project that has a lot of CPU intensive VIs and a lot of audio and the crackling was louder than the music. With these two simple changes all the noise vanished. Beautiful.

So if using an AD doesn't work for you, just try that and perhaps it will help.

[digitalolive]

"1) no pops on playback.
2) pops when I play my keyboard through DP
3) the pops themselves seem to follow a cycle, as if they are some kind of filter coupled to the complexity of what I'm playing. When holding a note or playing a passage, the first pop begins about when I start playing, then the second is about 20% quieter, the 3rd 20% quieter still, as well as about 50% later. The fourth is much quieter, and about 50% later than the previous one. "

I just got a Line 6 Toneport UX2 and I am getting the same symptoms with it. I play a guitar chord and hear a slow pulsing pop as the sustain dies off. When I play it back though, it's fine. I will try the aggregate device fix when I get home today and see if it works. Thanks for the tip!