Understanding recording levels and clipping

seanakaforty

New member
First thing's first: I am using a Fast Track Ultra audio interface by M-Audio. I'm a bit confused as to how I should set up recording levels and how exactly clipping works (It doesn't help that I don't understand the term "decibels" and its theory either...). So I'll just throw a bunch of questions at you and please let me know if my understanding of things is incorrect. As I understand it, a signal coming into an audio interface can overload either the preamp or the AD converter, correct? So a line input does not go through the preamp at all and therefore can only overload the AD converter, correct? How do I know if the AD converter is being overloaded or not when I'm using a line input; the front panel LED's on the Fast Track only indicate PREAMP clipping for the mic/instrument inputs, not clipping from the line inputs. In a software DAW/sequencer, when a track's meter is "in the red" and the level excedeeds 0db, is this referring to the AD converter being overloaded (are the headroom/clipping of the AD converter in my interface and headroom/clipping of a track in my software one and the same) or is the meter on my DAW's track referring to yet another stage in the chain that has been overloaded after the AD conversion? In other words, if line level signals don't go through the preamp at all, does this mean that I can record the line inputs as loud as I wants as long my Sonar doesn't show my track clipping? Also, I know that when the mic preamp is overloaded, the clipping is actually recorded and can't be reversed. But when the AD converter is overloaded, can this be corrected by simply lowering the volume of a track in the DAW after the fact?

Now, with all of that out of the way let me explain why all these questions came about in the first place. I started off using the built-in mic preamps in my Fast Track Ultra. This was pretty straight-forward: I raised the gain knob until the LED turned red and then backed off some. But now I've upgraded to a standalone mic preamp, so I'm running to the line input of my interface. So now the gain knobs don't effect the sound level at all (I take it line level signals don't need gain because they don't need to be "preamplified"?) and the LED's don't help me out either :rolleyes:. So do I just go by the meter's in my software DAW, and as long as I don't clip there, I'm OK?
 
Short quickie version- Use the software's track meter set to 'peak mode to monitor the AD input conversion level. That covers you on that end regardless of the type on input on the analog end. (Generally the level settings in the software won't effect record level -if in doubt set them to zero' initially.
Where ever things may end end up on the analog side keep your record levels on the peak meters well below 'zero for some head room -typically sustained levels -18 or so, peaks -6 is fine.

On the analog end whatever your using should be set within it's optimal range. Generally that output level will line up with the AD record level. If it dose not then you may have a slight mismatch in expected voltages in which case you can attenuate or boost the output or record lower.
 
Back
Top