I can’t tell you the number of times I’ve heard someone tell me you need to record as close to 0db as you can to “use up all the bits.” Much has been written about proper recording levels in the digital domain, and from a purely theoretical/best practices standpoint there really isn’t much more I can add – unless you’re working with really nice preamps that overload in a musical manner and add something desirable to the mix, with useable headroom of 96db for 16-bit recording and a whopping 144db for 24-bit recording, there’s no point in pushing your luck on tracking levels since digital gain once you have audio on disc is totally transparent and either 16- or 24-bit offer far more headroom than a modern rock mix will ever need.
That said – a practical example never hurt anybody, so after posting about this on a message board earlier today, I thought I may as well post it here as well – if you’re recording guitar anywhere remotely close to -0db, you’re probably going to have to turn the tracks down, by a fair amount, to not overload your master bus.
Below is a screen grab from the mix to my song “Badlands” off Zero Mantra.
It’s not immediately obvious from the image above, but at unity, both tracks are peaking at about -15db. At least on the M-Audio Profire2626 I was using at the time, that’s about where I generally tried to have levels come in. They’re bussed together into a master rhythm bus, where I’m taking another-3.5db off. This then goes into an overall mix with bass, drums, lead guitar, and clean and acoustic guitars in various points, as well. I’m using the Avatar kit from Superior 2.3 for drum sounds on this album, and in the drum bus where I’m summing each individual part of the kit, I’ve got the drums backed off -11db. The overall mix is getting a +7.5db boost from the master slider, for reasons that elude me at the moment – probably, by the time I’d balanced all levels, it was coming in a little lower than some of the other mixes, so I boosted it up for comparability. The master peaks at about -2.5db, which to be fair is a little higher than the -6db or so I usually target.
But, let’s walk through all those adjustments. We have guitars peaking at -15db, which are then getting lowered another 3.5db in the rhythm bus, to -18.5db, are being fed into the master bus where they’re increased another 7.5db (to effectively -11db), and the mix as a whole is peaking at about -2.5db.
So, I have rhythm tracks that are falling at about -11db, peak, in a mix with -2.5db of headroom. Another way of looking at this, is that if I had foregone all of those adjustments, raw tracks any higher than -8.5db at peak would actually have to get turned down in the final mix, or you would risk pushing it into clipping trying to get the mix balanced to the point you want. Sure, digital gain adjustments are transparent, but why even bother?
In the analog world, pushing your tracking levels could, at times make sense, since tape can add some attractive coloration as it compresses and distorts. Headroom on tape was quite a bit lower – I’ve seen measurements in the low 60s before you hit the self-noise noise floor cited – so tracking volume was something you wanted to be a little careful about, not to go too low. The move to digital, however, was supposed to remedy this, and in particular 24-bit audio has an obscene amount of usable headroom. Considering there’s nothing attractive about digital clipping, there’s no sense not playing it safe.
There’s a lot of great articles about recording levels on the internet, but this one, published on the Massive Mastering blog, is one of my favorites and would be a great place to start.