Diagnosing the causes of audio clicks 'n' pops

This post was first published in May 2014 at projectstudiohandbook.com/PSHforum

Back in old days of analogue, most pops and clicks in the signal chain were caused by poor interconnections, dodgy leads, plugs and sockets. Occasionally they would be caused by a thermostat clicking on or off in the studio fridge, but by and large they were easy to diagnose and fix. There were other problems and issues in the analogue studio, but a discussion of them is for another day.

So we were a little frustrated when earlier this week we applied a minor OS security update, and Logic Pro X bug fix update that left us with random click and pops during playback.

In digital audio, click 'n' pops usually mean digital sync issues, so we checked all our settings, sample rates, word clock terminations etc, and when we found a driver intermittently displaying its settings, we looked for, found, downloaded and installed an update. Still the clicks 'n' pops persisted.

Perhaps there was a problem with the audio files, but after looking at cross fades, zero crossing point settings, and painstakingly playing the project with each track solo'd, we couldn't detect a pattern.

Could it be audio engine overload? No, plenty of headroom there.

Next we decided to check for updates for all our plug-ins old and new. Perhaps there was an old component issue that the OS update had highlighted. Updating plug-ins is a laborious process. Here's what we updated ..

Trillian
Korg Digital Legacy
VSL special edition
NI Komplete (5Gb of update downloads!)
5 Dunende plug-ins (in so doing we found their licence system had changed so we had to migrate our licenses from Codemeter to iLok)

Phew! Several hours later, and after a restart .. yes! .. we still had our clicks and pops.

Perhaps they were in the monitoring chain? The only way to be sure was to bounce a finished mix in the box, move it to another system and listen. Nope, clicks and pops rendered in the audio.

Now we were getting cross! There was the possibility that we would need to update our OS to Mavericks. Several hours of reading the compatibility info at software vendors site convinced us that the update would be dangerous. 8 months since Mavericks was released and at least 2 essential parts of our system had drivers still in beta.

We decided to sleep on it.

The next morning we booted the system and sat looking at the screen cradling cups of tea. Someone said "I don't suppose it could be the Drop Box app?". We use Drop Box to receive audio files for mix-sessions. Never had a problem before, after all it's hardly an audio related app.

But worth a try, we quit it from the menu bar and fired up our Logic project. Were the clicks 'n' pops gone? Yes.

The moral of this story. When it comes to DAWs, the problem could be anything. A simple compatibility issue between any one of hundred of components and we're sunk. We lost 9 hours. Aaaargghhh!

We know you have a story like this too.

Thanks for reading.
FairFax