Sound meter in recorder vs software in post

F

fhammond

Well-known member
Hi,

I'm new to audio recording so my apologies if this is a silly question.

I've read that recording interview audio at between -12 dB and -6 dB is appropriate. I'm recording using a MixPre-3 and an MKE600. The mic is on a stand (to simulate a boom pole) about 12 inches away from me and pointed at about a 45 degree angle down at my chin. At a gain setting of about 50 dB, the meter on the MixPre shows peaks around -20 dB with most of the recording being between -20 and -30.

However, when I put the recording into Premiere and make no changes, the dB levels are right around -12 dB to -6 dB. I see the same thing in Final Cut Pro. Can someone explain to me why what I see on the meters during recording is so different from when I see in Premiere?

Thanks!
 
I don't know about Premiere, but FCP uses a non-standard scale by default, where zero is not full scale. I think the free Audacity DAW has full scale metering, as does most other DAWs (and audio editing software like Sound Forge). There are lots metering plug-ins available as well (free and otherwise), though I don't know if Premiere or FCP support third-party audio plug-ins.
 
Two different types of meters showing two different versions of the same end-product.

Look carefully at the meters on your MixPre-3. You'll see the solid meter level bouncing around -20dB, but you should see a very thin line of meter segment that shows a higher value. There will be a visible gap in the metering, and the thin line will hold its position for a moment. The solid metering is your average, and the thin segment is your peak.

NLE meters typically show Peak Program (PPM). Your audio hasn't changed at all, just how the meters read the levels.

Rick brings up a good point about non-standard scales. Some less-expensive recorders (Zoom and Tascam handhelds, for example) actually meter a little higher than actual. This is a design implementation aimed at inexperienced users, so when it starts to show a peak near or at 0dBFS, it actually still has a couple dB of headroom before clipping. Audio from these devices, when brought into an NLE or DAW, will meter low and often have to have gain increased in post.

I've not had much experience with FCP X (which is likely to change, since the latest OS update officially no longer supports FCP 7), but FCP 7's meters are pretty accurate. I do my audio post in ProTools, and the meters in FCP 7 show the right peak levels when I bring my exported PT mix back in.
 
To add to the confusion...

FCP, at least V6, had an auto anti clipping "function" built in that used some floating point something or other and adjusted some internal levels with out you knowing about it to make sure that the user couldn't do anything in the program to clip levels. So FCP metering is (was) fairly useless for non home projects.

Another thing that could be a factor is different scales. SD uses (or used, don't know if the new MixPres are different) dBu for their meters. Most software uses dBfs (full scale is 0 and you count down from there). So on the old MixPre 0 was 0dBu and the device didn't actually clip till +24dBu, where of course anything using a fs meter will clip if you try to go over 0.

Alex also made a good point about peak VS average. Peak is pretty much the same box to box but the average can change a fair amount depending on how they are averaging. There have been a number of different formulas used tailored to different users. The big variable is how much time they use in the average. A big window gives you a better overall look at the level but reads low with very dynamic material, a small window reads closer to the peaks but is not as good a look at your average program level. You may even be able to change the values in the MixPre.

A lot of older info on levels is referring to dBVU which has a window designed to simulate how a human ear perceives loudness and was fairly standard in analog mixers and recorders.

A lot of the hot and heavy worry about levels comes from analog days when you really had to work to optimize levels to avoid noise, tape hiss etc. Not that you shouldn't pay attention to gain staging but the window where you can get good results has grown from a peephole to a picture window, especially with gear on the level of SD. As long as you are not cranking levels up or down at any point you are probably OK. A red flag is if you are making a big correction at some point. Say if your trim is way down and later you are gaining way up, not a good sign. As long as you don't have to make a big move later in the workflow you are at a pretty good level.

I would work backward. Figure out what gives you the levels you want in post and set the MixPre to get you there. The Mic pres are so clean with the SD gear that you have a lot of room to play with out having to worry much about noise.
 
Noiz2 said:
Another thing that could be a factor is different scales. SD uses (or used, don't know if the new MixPres are different) dBu for their meters. Most software uses dBfs (full scale is 0 and you count down from there).
Click to expand...

The original MixPre and MixPre-D used analog scales on their mixers. The MixPre-D used the same meter design as the 301, 442, and 552 mixers, and there was also a way to alter meter ballistics, if I recall correctly.

The MixPre-3 and MixPre-6 both use dBFS. I've searched through the menus, and even read through the User Guide, to see if there were any deep-menu settings to change the meter ballistics. There are none.
 
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