Clipping compensation when using Built-In Output

L

liamcarey

New member
Hi, I wonder if anyone could shed some light on something that's really confusing me. Someone has sent me a mix to listen to in Pro Tools and when I played it back through my studio speakers (via and AVID HD interface) it was just insane distortion from the master output clipping, like +20dB of overload. It sounded like some kind of experimental industrial noise piece (it's meant to be a pop-country song). When I mentioned this to them they said that they hadn't noticed anything like it and I started to wonder if they must have something wrong with their hearing, because it was ridiculous. So just to be sure I played it back using the Built-In output on my mac and listened to it on headphones as that's how they had mixed it and the clipping was completely gone. What is going on - does Mac OS have some kind of clip compensation built in? If so, can it be turned off? I'm trying to explain to this person why you shouldn't go over zero on the master output, but without buying them a decent audio interface they can't hear why.

Any help with this would be greatly appreciated,

Thanks,

Liam
 
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The Orban Loudness Meter (free! download here) is something I discovered on this forum. Why not install it if you don't already have it and tell us what numbers you see when you add the file you're posting about? (Use the Analysis tab and click on the + at the bottom left to add a file.) It will look something like the attached image when done.
Screen Shot 2018-01-12 at 5.01.29 PM.png
Then we can all agree on what the file is, and you'll have something concrete to use to talk to the audio file's creator(s).
 
Hi Keith,

Thanks for your reply. Just to clarify - they haven't sent me a stereo bounce, I'm talking about a Pro Tools session. I gave them a full session to practice on and they sent me back their session file so I could take a look and give them some feedback. I've bounced it down anyway so I could run it through the Orban software and this is what it came out like:

Screen Shot 2018-01-13 at 21.45.00.png

As you can see - that's a lot of clipping. But like i said, when I play back the Pro Tools session using Built-in Output I can't hear any distortion. Since my original post I've also played the session back through my RME interface at home and my mate's MOTU interface - both were clipping like crazy. So if it clips when played through an AVID HD system, an RME interface, a MOTU interface and when bounced out of Pro Tools, but doesn't clip when played back through the mac's Built-in Output I can only surmise that it is something that the Built-in Output is doing, but I haven't a clue how or what?

Liam
 
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Is the Pro Tools master bus meter reading over 0dBFS?

[Edit] Looking at your first post it looks like the answer is yes.
 
I wish I knew the answer to your question, because everyone else in this thread is ignoring it and trying to troubleshoot a problem you aren't having.

Good luck.
 
It may be that the Mac audio system can detect a floating point stream and adjust the gain to compensate.

If you just want to explain why clipping is bad there are plenty of resources out there. Rehashing that here is a waste of (my) time.

I'm more interested in this: Why is it so loud on your system? Is it actually that loud on their system or is there some difference between the PT setups that's causing this? If it's not actually that loud on their system then explaining why clipping is bad doesn't help. If you don't want to use your Mac's normal audio output to audition the song then knowing why it does't clip doesn't help, unless that tells you why it does clip using the other outputs.
 
Well, the file you bounced is thoroughly squashed and its average loudness is effectively 0dBFS, so I'm not surprised at the number of times peaks exceed that.

Who knows, maybe the system audio stack has the sense to normalize so as to not destroy speakers (or ears if you've got earbuds on, more likely)?

Anyway, I guess this is some interest to someone, but why bother trying to puzzle out a project playback problem for a mix that is completely wrong level-wise, not to mention compressed/limited beyond recognition? Tell them to fix the dang mix.
 
Turn the built in audio system all the way up. Find whatever place it has a volume control and put it at 100%.

I don't know ProTools really, but if you can just pull down the master fader and then it works, do that.
 
keith.rogers said:
Anyway, I guess this is some interest to someone, but why bother trying to puzzle out a project playback problem for a mix that is completely wrong level-wise, not to mention compressed/limited beyond recognition? Tell them to fix the dang mix.
Click to expand...

Maybe on their system it's not over 0dBFS. That amount of clipping doesn't seem like people just trying to mix loud, it seems like a technical bug of some sort. I'd first find out what the original user had it set for.

Or I'd just turn down the master and move on.
 
bouldersoundguy said:
Maybe on their system it's not over 0dBFS. That amount of clipping doesn't seem like people just trying to mix loud, it seems like a technical bug of some sort. I'd first find out what the original user had it set for.

Or I'd just turn down the master and move on.
Click to expand...
Still seems like looking for the least likely answer, but there's got to be at least one other PT user here who could do the same import and report what they see. Or, if there's some reason that can't be done or be conclusive, I'd ask the owners of the project to take a screenshot of the project while it's playing back around a certain point, and the OP do the same - maybe do that first and send so they can duplicate. Compare sliders and peaks, especially the master (not a PT user but assuming those are all obvious). Next would be a non-normalized bounce (by the owners) and run the same loudness/peak analysis.

Without more data it's just a guessing game, literally.
 
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