-18 optimum recording level question and VU meter.

[keano12]

Very confused... I know that for plugins and resolution etc -18 is a good recording level to shoot for. I have a VU meter Klanghelm. I have a sine wave at -18 which shows on my VU meter at 0 reading -18.

 

So when recording I shoot for 0 on the VU meter (-18) but when I do the my level in my DAW is around -5.4db?

[stardustmedia]

That depends on the source you're recording. This is normal. The VU meter is kind of a RMS meter, it doesn't "show" transients like a peak meter. For instance with a very short closed hihat, you'll hit 0dBFS way before you hit -18dB RMS (respectively 0 VU). 

[David Nahmani]

I know that for plugins and resolution etc -18 is a good recording level to shoot for. 

Snake oil. Just don't peak at 0 dB FS and you'll be fine. The vast majority of plug-ins behave the same independently of the level you feed them, and for those that don't (guitar amp emulation, analog compressor emulation etc...), it's a matter of taste what you want them to sound like and how much signal you want to feed them, so in that case, use your ears. 

 

This, to me, is akin to asking someone recording in analog to never, ever go above 0 VU. Doesn't make sense. 

 

There is a LOT of misinformation out there. Don't believe the hype. Use your ears. 

[MikeRobinson]

Also – and please correct me if I am wrong on this – the internal processing that is done by Logic is done using "floating point" math (basically, "scientific notation") which isn't subject to the numeric range restrictions of however-wide "integers."  

 

If you see something "go orange," it means that the level is so "hot" that it would have been clipped, had it been an integer ... but, it isn't.  It's floating-point. So, Logic is still able to represent this "out of bounds" waveform precisely.

 

If you see something "go red," it means that you are in trouble, because the signal is headed for integer output, and it's too hot ... numerically, too big ... to fit in the chosen number-of-bits.  The numeric value which Logic is now holding cannot be represented:  if stored, the value will be truncated mangled destroyed.  (Music-file delivery formats (MP3, WAV, what have you) consist of integers of some number-of-bits each.  Logic also supports other file-formats, not intended for direct playback, which do not.)

 

My understanding is that "0 dB FS" basically corresponds to "that maximum-possible integer," beyond which mathematical truncation would occur:  destruction, not "distortion," in the digital world, i-f the signal is going to be reduced to a "delivery-file integer" at that point in the pipeline.