Recording Meters and Levels

Recording Meters and Levels

When I started out in Sound Recording I was confused by the different Recording Meters and Levels, surely that was impossible? Why record at -12dB on a digital system but aim for 6 on a VU meter? So here is a rundown of what it all means.

Digital Recording Meters compared to analogue systems

Digital is obviously here to stay for many reasons but an important note in terms of levels are how the different systems deal with very loud signals. Sound is always analogue at the source and how we hear it only in between can it be digital.
Analogue recording systems gracefully handle extremely loud signals and slowly get completely messed up. Digital on the other hand just cuts off and dies horribly!. This is due to Sampling theorem and the Dynamic Range of data that can be stored on a sample before it starts to distort. Thus it is very important to have headroom and understand your meter system.

Before we begin:

Handy comparison before we get into more specifics:
recording meters

Digital Recording Meters and Levels

These range from around -60dB up to 0dB. The zero has no actual value other than the loudest sound that can be free of distortion. When measuring in just dB it is only a representative change like a percentage or ratio compared to another value.

Example: If I said his voice was 20dB higher than hers, it would be his voice is 10 times louder than hers. Just saying my voice is 10dB means nothing unless compared to something else, if I said my voice should be at 10dBu or dBA then it means something. (But it will get it`s own topic soon)

 

PPM Recording Meters and Levels

PPM (Peak Programme Meter - BBC)

Range = 0 to 7 line-up: 4 (needle straight up) Max level: 6 Each division: 4dBs Average level: 5 Edit suite/CTA measurement - See a real version of a PPM meter system

VU Recording Meters and Levels

VU (Volume Units - USA) line up:-4 (between 3 & 5 black) Max level: +4 (Red notch right of 3) Each division: 1dB Average level: 0 Analogue VTRs

 

Digital Recording Meters and Levels

Digital line up: -20 Max level: 0 Each division: Varies Average level: -14 Digital VTRs, Digital Recorders