Ok, so the status quo for digital recording at the moment is 24/96. That would be 24 bits at 96 kilohertz. This is a fair step up from when I got started. CDs are 16/44.1 and most of the stuff around at the time was as well. Why make the jump and fill up your hard drives faster? Two reasons.
Without getting into a long scientific discussion let's just cover all this stuff about "headroom" being better in a 24 bit system and move on. If you're working at 16 bits and you record something with a lot of dynamic range, you have to hold the volume down so that the peaks don't run out of room. You wind up with a lot of quiet sounds in there. Later on if you're looking to normalize or compress that signal, there are only a few bits describing those quieter sounds. If you record at 24 bits then you don't need to record as hot because there are more bits describing the quieter signals. You can raise them up in volume and maintain better quality. The only thing you need to watch out for is converting down to lower bitrates. Some poorly implemented converters accomplish the job by just lopping off the least significant bits, good ones do a lot of math to make sure everything translates in the best possible fashion.
Now let's get on to sample rate. The Nyquist rate is the speed at which you need to sample to obtain frequencies that are half of that rate. So a 44.1 kHz system can capture audio frequencies up to 22.05 kHz which is above the hearing range of humans, so we're all good right? Not so fast. There are frequencies emitted by almost any source that are above our hearing range. What happens if you take a sine wave at 25 kHz and another one at 26 kHz and play them back? They're both above our hearing range, but you would actually hear a beat frequency where the two interact at exactly 1 kHz which is right in the middle of our hearing range.
There are mics now that are capable of capturing frequencies in excess of 100 kHz. Pair them up with a 96 kHz recording system and you're capturing just a ton of data that we can't hear, but some of the interaction between those frequencies up there will translate into stuff that we can hear.
So it's not hard to see why it's worth making the jump up to a 24/96 system or even higher. This is one of those areas where if good enough isn't good enough, you can take some extra effort that might seem superfluous but will actually improve your work in subtle ways. Why? Do low bitrate MP3s sound OK? That depends, do you just want to hear that catchy song from the radio and enjoy the hook on your earbuds? Or will you be trying to reproduce that same song in a venue with pristine line arrays for a discerning audience? I'd be looking for higher bit and sample rates myself in the second situation.
Hopefully that sheds a little light into the murky depths of the digital audio realm for my fellow Brethren of the Knob and Fader. Feel free to hit the comments section or contact us through Facebook or Twitter to further the subject.