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A question about gain-staging with VU meters vs. Peak/RMS
Old 12th November 2018
  #1
Gear Maniac
A question about gain-staging with VU meters vs. Peak/RMS

Hello,

I am in the process of establishing proper gain structure across my studio. As I configure my virtual instruments (particularly drums), I'm getting confused by a few things:

1. From what I understand, it is best to hit the DAW (or virtually "hit the DAW") with average RMS levels at around -18, and peaks at around -12. All this before any inserts. Yes? Next question:

2. I've also read that peaking at 0 on a VU meter (and sorry if I'm using incorrect terminology here) is in some way analogous to this wonderful -18 dB headroom level that we all love. Am I correct so far? OK, now here's where I'm getting (more) confused:

3. I'm noticing that when calibrating an instrument, say a kick or snare, to -18 RMS and -12 peak, that the VU meter only peaks about halfway. In fact, to crank the VU meter up to 0, I've found that I have to add gain to the point where I'm looking at something more like -12 RMS and -6 peak.

Sooooo, clearly I am not understanding something properly, or something is not calibrated properly in my meter setup...or somewhere else?

Any light you can shed on this topic is greatly appreciated :-)

Thank you!
Old 12th November 2018
  #2
Quote:
Originally Posted by Ishkash View Post
Hello,

I am in the process of establishing proper gain structure across my studio. As I configure my virtual instruments (particularly drums), I'm getting confused by a few things:

1. From what I understand, it is best to hit the DAW (or virtually "hit the DAW") with average RMS levels at around -18, and peaks at around -12. All this before any inserts. Yes? Next question:

2. I've also read that peaking at 0 on a VU meter (and sorry if I'm using incorrect terminology here) is in some way analogous to this wonderful -18 dB headroom level that we all love. Am I correct so far? OK, now here's where I'm getting (more) confused:

3. I'm noticing that when calibrating an instrument, say a kick or snare, to -18 RMS and -12 peak, that the VU meter only peaks about halfway. In fact, to crank the VU meter up to 0, I've found that I have to add gain to the point where I'm looking at something more like -12 RMS and -6 peak.

Sooooo, clearly I am not understanding something properly, or something is not calibrated properly in my meter setup...or somewhere else?

Any light you can shed on this topic is greatly appreciated :-)

Thank you!

1 & 2. Especially when tracking, -18dBFS is a common target level because a lot of A/D converters are calibrated so that an incoming audio signal of 0VU from the preamp (which is usually +4dBu/1.23 Volts in pro gear) is converted to -18dBFS. But -18dBFS isn't universal by any means. You'd have to check the specs of your converter. Some are calibrated to -22dBFS, -20dBFS, -16dBFS, etc., and some are switchable. Either way the whole point of it is to leave enough headroom for peaks.

3. Traditional VU meters are for measuring average RMS level, in other words they are much slower than peak meters. They don't react fast enough to measure the fast attack of a kick or snare signal. That's why your VU meter is only going "halfway." The best way to calibrate your system is to use a "static" sound, like a 1k tone signal.

Last edited by Bender412; 12th November 2018 at 07:45 PM..
Old 12th November 2018
  #3
Deleted c0657d7
Guest
Quote:
Originally Posted by Bender412 View Post
3. Traditional VU meters are for measuring average RMS level, in other words they are much slower than peak meters. They don't react fast enough to measure the fast attack of a kick or snare signal. That's why your VU meter is only going "halfway." The best way to calibrate your system is to use a "static" sound, like a 1k tone signal.
True, and I'll add that a PPM (Peak Programme Meter) type is better suited for gainstaging singular signals and will align well with '0' = -18dBFS (or any other chosen headroom range).

*To be calibrated with 1kHz sine aiming at; -18dBFS = -6PPM*
Old 12th November 2018
  #4
Gear Maniac
Quote:
Originally Posted by Bender412 View Post
1 & 2. Especially when tracking, -18dBFS is a common target level because a lot of A/D converters are calibrated so that an incoming audio signal of 0dB VU from the preamp (which is usually +4dBu/1.23 Volts in pro gear) is converted to -18dBFS. But -18dBFS isn't universal by any means. You'd have to check the specs of your converter. Some are calibrated to -22dBFS, -20dBFS, -16dBFS, etc., and some are switchable. Either way the whole point of it is to leave enough headroom for peaks.

3. Traditional VU meters are for measuring average RMS level, in other words they are much slower than peak meters. They don't react fast enough to measure the fast attack of a kick or snare signal. That's why your VU meter is only going "halfway." The best way to calibrate your system is to use a "static" sound, like a 1k tone signal.
Thanks for your response Bender. So, say I'm gain staging a virtual drum kit: each instrument of the kit is on a separate track, and I'd like to get healthy recording levels (pre-mix), so I tweak the level of each instrument (pre-fader) to...what exactly? Should I be trying to hit 0 on VU meters? That feels a little hot IMO, especially considering that my plan is to then saturate, compress and/or EQ the sound. Or should I be calibrating to -18 RMS, -12 peak instead?
Old 12th November 2018
  #5
Gear Addict
 
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I feel like if the recording studios of the 70's mic'd individual drum pieces, they would see the tracks on a vu meter through the desk. and i imagine they aimed for roughly zero vu on everything until they made choices based on taste. Im curious if 0 vu was the baseline for many recording setups.
Old 12th November 2018
  #6
Gear Guru
 

Quote:
Originally Posted by Ishkash View Post
1. From what I understand, it is best to hit the DAW (or virtually "hit the DAW") with average RMS levels at around -18, and peaks at around -12. All this before any inserts. Yes? Next question:
If you're working with drums for example then it's not a particularly wide range between your average -18dBFS and peak -12dBFS, only about 6dB to fit your transients and peaks etc. So I wouldn't actually worry about -12dBFS much. You have 18dB between your average and 0dBFS so that's plenty of room.

Also consider what you'll be doing to your signals. Typically in music we tend to limit the dynamic range of signals (meaning from average to peak, which some feel should be called something else actually). So if you have a drum kit I'm going to guess you're going to squash that signal anyway. In other words: If you have a drum kit reading average -18dBFS and peaks are up around -4dBFS BEFORE you start processing AND your processing is likely going to include compression then don't worry about it. Your peaks aren't going to be that high when you're done.

Quote:
Originally Posted by Ishkash View Post
2. I've also read that peaking at 0 on a VU meter (and sorry if I'm using incorrect terminology here) is in some way analogous to this wonderful -18 dB headroom level that we all love. Am I correct so far? OK, now here's where I'm getting (more) confused:
0VU is an analog measurement, not digital. If you calibrate your converter to 0VU = -18dBFS (average) then that gives you 18dB before exceeding the absolute digital maximum "zero" value.

Quote:
Originally Posted by Ishkash View Post
3. I'm noticing that when calibrating an instrument, say a kick or snare, to -18 RMS and -12 peak, that the VU meter only peaks about halfway. In fact, to crank the VU meter up to 0, I've found that I have to add gain to the point where I'm looking at something more like -12 RMS and -6 peak.
Ok, but why worry about it? This is all virtual and already digital, and you're not going to settle for that one component but instead use a whole drumkit, right? So just balance the kit and keep an eye on levels to avoid clipping. You don't have to complicate things. If you want you can set the output of all your drum tracks to a group ("aux" in Pro Tools) and look at the meter there to see the level of the sum of the entire drum kit and also adjust the level there.

Also remember that a sine wave looks one way on a VU meter and a kick drum completely different. They're different animals. The VU meter's needle has a lag both rising and falling and that lag helps us see something that feels more like what we hear, but it's probably more true with longer signals. A kick drum and a snare are short. So, it's not really clear that the VU meter will catch the level "accurately", for lack of a better word. So this to me is textbook "don't worry too much about it".

Quote:
Originally Posted by Ishkash View Post
Thanks for your response Bender. So, say I'm gain staging a virtual drum kit: each instrument of the kit is on a separate track, and I'd like to get healthy recording levels (pre-mix), so I tweak the level of each instrument (pre-fader) to...what exactly? Should I be trying to hit 0 on VU meters? That feels a little hot IMO, especially considering that my plan is to then saturate, compress and/or EQ the sound. Or should I be calibrating to -18 RMS, -12 peak instead?
Just balance the kit. Don't exceed 0dBFS and don't otherwise clip the signal. You can look at a later stereo bus to figure out how loud the kit is as a whole as that may be easier - either looking at the master out bus or create a group/aux and look there instead.

If you want to process one individual component on one track with for example a tape-emulation plugin that has been virtually set to nominal level = -18dBFS then you should be able to hear the effects of the plugin get more and more significant as you push the level higher into the plugin. At an average of -18dBFS I'd expect it to change the signal less than at -10dBFS. Just push the signal into the plugin until it sounds the way you want.
Old 12th November 2018
  #7
Gear Maniac
Quote:
Originally Posted by mattiasnyc View Post
If you're working with drums for example then it's not a particularly wide range between your average -18dBFS and peak -12dBFS, only about 6dB to fit your transients and peaks etc. So I wouldn't actually worry about -12dBFS much. You have 18dB between your average and 0dBFS so that's plenty of room.

Also consider what you'll be doing to your signals. Typically in music we tend to limit the dynamic range of signals (meaning from average to peak, which some feel should be called something else actually). So if you have a drum kit I'm going to guess you're going to squash that signal anyway. In other words: If you have a drum kit reading average -18dBFS and peaks are up around -4dBFS BEFORE you start processing AND your processing is likely going to include compression then don't worry about it. Your peaks aren't going to be that high when you're done.



0VU is an analog measurement, not digital. If you calibrate your converter to 0VU = -18dBFS (average) then that gives you 18dB before exceeding the absolute digital maximum "zero" value.



Ok, but why worry about it? This is all virtual and already digital, and you're not going to settle for that one component but instead use a whole drumkit, right? So just balance the kit and keep an eye on levels to avoid clipping. You don't have to complicate things. If you want you can set the output of all your drum tracks to a group ("aux" in Pro Tools) and look at the meter there to see the level of the sum of the entire drum kit and also adjust the level there.

Also remember that a sine wave looks one way on a VU meter and a kick drum completely different. They're different animals. The VU meter's needle has a lag both rising and falling and that lag helps us see something that feels more like what we hear, but it's probably more true with longer signals. A kick drum and a snare are short. So, it's not really clear that the VU meter will catch the level "accurately", for lack of a better word. So this to me is textbook "don't worry too much about it".



Just balance the kit. Don't exceed 0dBFS and don't otherwise clip the signal. You can look at a later stereo bus to figure out how loud the kit is as a whole as that may be easier - either looking at the master out bus or create a group/aux and look there instead.

If you want to process one individual component on one track with for example a tape-emulation plugin that has been virtually set to nominal level = -18dBFS then you should be able to hear the effects of the plugin get more and more significant as you push the level higher into the plugin. At an average of -18dBFS I'd expect it to change the signal less than at -10dBFS. Just push the signal into the plugin until it sounds the way you want.
Thanks for your helpful response, Mattias. I've appreciated your input on a variety of posts over the years.
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