Peaking!

Hi again,

I am using the Edirol UA-25 USB audio interface and find that it seems to peak very easily - that is, it sets of the 'Peak Limiter' LED on the Edirol interface and shows volume bars in the red in the recording software. e.g. when recording electronic drumkit or even some synth programs that have a bassy pulse, peaks seem to occur even when playing at (what I believe to be) reasonable volume. If i decrease the sensitivity of the input to the UA-25, then the recorded track sounds too quiet (albeit without peaks). Is this a technical limitation of my audio interface? Would upgrading to a different type of interface (Firewire?) help in this respect? I can't imagine it has to do with the transfer rate... I'm just not sure. I will give two example problems to clarify:

1. Recording a Roland Electronic Drumkit, hitting the bass or snare too hard causes a peak, but otherwise, signal is not distorted. So I turn down the 'sens' on the UA-25 but this results in a rather quiet drum track! (At the moment I then go on to layer duplicate tracks in software, or use some other crude method - like overdrive - to boost the volume of the track)

2. Bassy pulses on certain synth sounds can also trigger peaks. (at the moment I just stay away from these sounds, but I would like to use some of them!)

However, when plugging my guitar in, or using a microphone (SM58 mostly) I don't have a problem with peaks. Any tips about this would be really helpful. Thanks again.

Cheers,

Albert

IMHO the best way to solve this problem is with an external limiter. This allows you to get a lot of level on the track without distortion. I know that some will say it's better to record at 24 bit at lower levels then boost it in the mix and this gives you the same performance as 16 bit. But to me that's a waste of bandwidth. If I'm going to record at 24 bits I want all that dynamic range and lower noise floor.

if you're recording in 24bit then anything over -48db is at a higher fidelity than 16bit audio.

What a great way to put it simply. By "fidelity", are you referring to dynamic range?

Albert-- the emphasis on pushing the levels close to the red is somewhat outdated if you're recording 24-bit digital. The reasoning is long and complicated, and you can run a search for it, but 24-bit digital does not have the inherit noise floor of analog tape, and it has more dynamic range than human hearing, so there is little need to obsess about getting close to peak level.

Also the distorted "peaks" you are referring to are technically called "clipping" or "digital overs." A "peak" is just the loudest part of any soundwave-- there's nothing wrong with "peaks" unless they actually "clip."

you said:

If i decrease the sensitivity of the input to the UA-25, then the recorded track sounds too quiet (albeit without peaks).

That's correct, go ahead and record with the track too quiet, and then use a plugin effect, either a limiter or a compressor to bring the level back up. This is exactly what compression and limiting are for-- they "limit" or "compress" the difference between the loudest and quietest parts of a sound, allowing you to "turn up" the main body and impact of the sound, WITHOUT turning up the "peak." So the "main" part of the sound gets louder, but the peak doesn't.

Make sense?

You might find it beneficial to check out a book such as Modern Recording Techniques or Home Recording for Dummies to refresh your memory and catch up on some of the developments in the past few years.

Cheers.