Pro Tools Metering Accuracy
 

I'm wondering how accurate are the meters, or rather which meters should i trust.

In mix control (focusrite) meters are clipping while in pro tools they aren't sooooh which ones are correct now :confused:

I'm not getting any distortion tho, however I'm just curious what's up with the meters.

any suggestions ?

Re: Pro Tools Metering Accuracy
 

at which stage? input or output?

Re: Pro Tools Metering Accuracy
 

input, output seems ok

Re: Pro Tools Metering Accuracy
 

Check that your ProTools meters are set to pre-fade.

Oh, and if your input stage indicates clipping you should turn your input gain down - period. There's no reason to use up every last bit of headroom anywhere in the chain.

best,
rich

Re: Pro Tools Metering Accuracy
 

pre or post fader doesn't matter really, it clips in mix control and it doesn't in pro tools. I have some hardware inserts and that's my main thing, because when I return the signal to pro tools it doesn't clip but in MC it clips. that's why i'm not sure which meters to trust. If I turn the gain down on saffire 56 the levels go drastically down, it's very sensitive. anyway, the whole thing is just about metering, if i had same results on input metering in MC n Pro Tools i wouldn't question, but if 2 separate software show 2 different things then I need to know which one to trust.

btw on the output, I have my old acid 6, and sometimes when I put limiter in Pro Tools (master fader in PT doesn't clip) however In acid when I drag the same file it's gonna go clipping by .1, .2, .3

there has to be something wrong somewhere. also if you didn't see watch the video below

http://www.youtube.com/watch?v=Rmxfu1tIuQY


Thanks

Dot

Re: Pro Tools Metering Accuracy
 

If it already clipped inside the Saffire, then the signal being delivered by the Saffire to PT is just under clipping. It's clipped, but PT doesn't know that because the digital signal being delivered to it doesn't exceed 0 dBfs (a digital signal can't exceed that, by definition). If you could deliver a PT interface analog input the exact same analog signal that clipped the Saffire, it would clip it. The red clip light should come on when a certain number of consecutive samples are at max. I think it used to be 3. If it doesn't come on, it's a bug. But really, if you need the red light on input, you're tracking way the heck too hot. Way way way. Turn down the mic pre gain by about 12-18 dB.

Re: Pro Tools Metering Accuracy
 

yes it would make perfect sense if PT wouldn't clip at all but it does if i raise the level so both saffire and pro tools are clipping. What i say is just the accuracy thing going on. saffire just clips faster. and I don't record at clipping really, I always leave at least 3db headroom minimum but usually from 6-10db. It's just interesting having two different readings from same inputs. And again everything you say makes perfect sense, however the only thing is that if i'd go all way up with clipping in MC pro tools shouldn't clip at all, and it does. Its just clipping at different levels

Re: Pro Tools Metering Accuracy
 

From what I understand this sort of thing has to do with how many consecutive samples at DFS (digital full scale) are counted before the clip warning is lit. Some systems light up at 1 -others require 4 -some even more. Obviously the system can only see level up to DFS. I don't know what the number of DFS samples the ProTools system needs to call it a clip.

Hope this helps -others will chime in eventually and explain in better detail.

all the best

Bruno

Re: Pro Tools Metering Accuracy
 

I think Bruno probably has it right. The two devices use different rules about how many samples in a row have to be full scale before it flags it. There's no set standard on that, so both rules are arbitrary. It could even be that the focusrite is measuring the analog circuit for clipping, in which case, it would be impossible to reconcile it perfectly with any digital system's clip meter.

Knowing focusrite, they probably set their units to flag anything that pushes the limits at all. I don't know which Saffire model you're using or whether it has a way to meter lower signals precisely. If you can get it to tell you when a 1 kHz sine wave is sitting at exactly -18 peak, and see if Pro Tools also shows that reading on it, then you'd have something to go by. Clip meters just aren't that clear a reference point, especially in the world of A/D where the analog line amps are pushing their headroom pretty hard with anything over -6 except in really expensive units.

Re: Pro Tools Metering Accuracy
 

:D thanks guys, it's all clear to me now. I'll do some more tests in the future but the answers i got satisfy my curiosity. The only thing that sometimes i wonder about is that the snares or hihats i usually send to hardware processing. They clip in MC and stay good in PT (they sound good in my ears tho) but that's just a little thing on the side. I guess i should trust my ears more than meters, but they good for visual reference.