I'm really new to recording, but I've been getting on well using the Tascam 2488 Neo 24-track digital recorder. However, when I create a master and then burn to CD, the overall volume is low. I record at about ‑10dBFS to avoid clipping and then use the compressor at mixdown to boost levels and even things out. This does raise the volume a tad, but nowhere near to that of commercial CDs. Am I correct in thinking that I'll have to use a lot of compression and limiting to get the levels to where I want them?
Via SOS web site
SOS Technical Editor Hugh Robjohns replies: Indeed, you will find it very hard to match the insane levels of some commercial CDs, but with a little compression and limiting you should be able to produce something that doesn't sound excessively quiet in comparison.
There are lots of ways of approaching this but, in general, when you're working on a track that is fundamentally well balanced but lacking in overall volume, I would start with some wide‑range and gentle compression. Typically, I would use a very low ratio — say 1.5:1 or even lower — and set it up with a very low threshold of around ‑40dBFS, so that it is slightly squashing everything in the mix, from the loudest to the softest instrument, all the time. This gives a very subtle and homogenous sound and is very different to the more typical use of compression with higher ratios and higher thresholds, which only affects the loud bits and for only some of the time.
Using this low‑threshold level, very gentle compression technique you can often squeeze as much as 8dB of gain reduction without the material sounding squashed at all. Adjust the attack and release times to suit the track — slower rather than faster is usually the right way to go for smooth level control — and then crank up the make‑up gain to raise the level close to 0dBFS.
The track will now sound significantly louder than it did, but there will still be spiky transients poking up above the main body of the waveform, and these are now restricting the total volume you can achieve. So the next process is to shave off those brief transients with a fast‑acting limiter and then wind up the make‑up gain again (unless your limiter does that automatically, as many do) to give another 2‑4dB of level increase.
By using this simple approach of a low‑threshold, low‑ratio compressor followed by a good limiter, you should find the material is substantially louder than the original mix track, but still without sounding overly compressed. However, this is obviously an artistic judgement call that only you can make: how much 'squash' will you accept for a louder‑sounding track? Sometimes you can only squeeze a few decibels before it starts to sound damaged, and sometimes you can manage 10dB without obvious problems.