Question about recording levels

[melbendi]

I'm recording audio from LPs with Audition on a MacBook 17" (Mid-2010, standard sound card) through a McIntosh MP-100 phono amp (which, oddly enough, only has "high" and "low" output levels - it's set to high).  I'm recording 24-bit 96kHz audio, but my recording levels are only around -6 to -10, which is quite low.  It may just be the limitation of the phono amp, but I thought I'd ask and see if there might be anything I'm missing within Audition that will allow me to record at higher levels without losing quality?  And another question I have is, does boosting levels in Audition effect quality? Thank you for your help!

[SteveG_AudioMasters_ · Accepted solution]

That's pretty much the correct sort of level to use, and it's not low at all. Always when you are recording into a system with a fixed ceiling (0dB), you should leave sufficient headroom to allow for anything that accidentally gets over your notional peak level. On professional gear, it's not recommended to record with peaks any higher than -12dB, or in some cases, even -15dB. That way 'accidents' can be recorded without distortion.

Other stuff: if you're recording using a 24-bit system, then you are losing no quality at all. What technically happens is that you theoretically lose a few dB of dynamic range - but in practice you don't, as there's no physical way you can use all of the dynamic range in a 24-bit signal anyway. At 6.02dB/bit, if you record at a peak of -12dB you are losing 2 bits out of 24. Only you aren't, because it's not physically possible to record that much dynamic range in the first place! Even if you lost four bits, that would still leave you 120dB of dynamics, and the best systems in the world can't reach that level; the Laws of Physics see to that. So no loss, and potentially some gain, especially as there's no vinyl in the world that's anywhere near that good!

And by recording at 96kHz, you are putting your recording system under rather more strain than it needs to be, and 50% of what you will be recording is nothing but noise - no useful signals above 22kHz, which says that sampling at 44.1k is more than adequate. There used to be arguments about brick-wall filters around 20kHz having strange effects on signal phase, which resulted in a slightly 'cloudy' sound, but frankly nobody's using that style of converter at all these days - everything's massively oversampled in the converter, and there are no artifacts at all to detect. This has all been checked out by a reputable academic study - under carefully controlled conditions using excellent equipment, nobody can tell the difference between 16-bit 44.1k sampling, and 24-bit 96k. It makes sense for processing reasons to use the bit depth, so 24-bit recording is fine - just don't bother with the 96k unless you are trying to record bats!

[melbendi]

Thank you for your reply, Steve.  I'm glad to know my levels are correct.  I'm boosting them in Audition and so far, they sound good!    I appreciate all the knowledgeable info and expert advice!