The Bit Depth Monster Will Eat You and Swallow You Whole
Originally Written for LIve2Play Magazine
Who’s ready to get nitty gritty? Or should I say, bitty?
Some of us had the benefit and joy of having worked in analog before the digital studio invasion, and you’ll often hear engineers pining over the good old days of quarter inch tape. Just open the conversation in any gang of self-respecting engineers and you are eventually going to hear “Digital SUCKS!”
But analog was dense and clunky. Expensive to maintain and required a lot of extra equipment and staff. Hello, obsolescence!
Flip forward 15 years to the digital revolution and average working musicians are operating their own affordable project studios. Arguments about whether this is good or not abound. But digital is here to stay. Suck it up, purists.
So today, we’re talking ‘bout bit depth. Yes. I know. You’ve never heard of it before. It’s geeky and technical. But very important to the project engineer. Here’s why:
DAWs are driven but the underlying reality of sampling rate. Sampling rate is simple, even though most only know more is supposed to be better. What it tells you is how many samples per second of an analog sound wave can be recorded by your DAW. 44.1 equals 44,100 slices of the wave per second.
Your ears hear analog waves as a continuous piece of information. Your DAW grabs enough slices to trick your ears into believing that they are hearing the entire sound wave. The more samples per second, the closer the reproduction comes to the analog sound wave. There is a lot of data that says most people can’t hear the differences between lower and higher sampling rates, but that’s a brawl for another day.
What’s most interesting about all of this obsession in the digital audio community about increased sample rate, is that when you get to the mixing OUT to a single stereo digital source, our world hasn’t really progressed very much.
Think of bit depth as a finite tunnel at the end of your recording project. You have a 24 bit tunnel. Only a certain number of “binary words” made up of 0s and 1s (the alphabet of digital) will fit into the tunnel. Words past the capacity of the tunnel have to go somewhere else. In audio, they go to that magical place called “away.” Like where we throw all our trash and stuff we should probably be recycling right now.
Like a freeway, where five lanes have to merge into two at the scene of an accident, the tunnel gets overwhelmed with data that wants to get through. But unlike the freeway, where cars wait their turn and crawl through (this is how your internet connection also deals with the problem), the music tunnel has no choice but to eliminate extra bits when it can’t handle anymore – so imagine those cars just flying off the side of the road now. This is called truncation. Information gets chopped off the ends and goes to “away.” (Someday we should all visit this place just to see all the stuff that is there. It’s probably like a museum by now.)
In real audio terms, the dynamic range (aka “headroom”) in your recording becomes smaller. Your stereo field may shorten and narrow. Longer trailing reverbs will disappear, the quality of certain EQs will be diminished, and your overall sound quality will suffer. There may even be distortion. This is obviously not ideal if we were hoping that higher sampling rate was helping our sound quality.
Maximum bit depth hit 24 about ten years ago. And that’s where it has stayed, due mostly to determinations by the computer industry. Even odder is that bit-wise, music delivery methods keep getting smaller as our sampling numbers go up. CD quality means that even if you have sent your final data out in 24 bits, it will have to be “dithered” (think further truncated) down to 16 bits. Convert your files to mp3s and forget it –you’re recording is now very far from its original 24 bits. Engineers raised in analog will tell you they hate the sound. They may be the only people out there who can really hear the difference, but that still tells you something.
And though people will argue all the time that all of these minor differences don’t matter at all, the reality is there are times when they do and times when they don’t. If you have absolutely STELLAR recording skills, then maybe not. If you are a newbie with simple equipment, then maybe a lot more. If there is one thing you will learn in the studio, it’s that you can’t put something back in that isn’t there in the first place. And quality is one of those things.
So how do you fend off the bit depth monster and keep him from eating your recordings for lunch? Below are some bit conservation suggestions:
Remember that when you mix, all the information has to go somewhere. Just because you CAN record 150 tracks and use 10 plug-ins on each track doesn’t mean that you should. If you have overwhelmed your stereo field in the first place, you may lose some quality during truncation. Sometimes less is more.
Use routing and plug-ins efficiently: subgroup like tracks that share plug-ins into the same Aux track whenever possible to reduce the number of instances that a plug-in is running (this will also save you processing power). Use plug-ins like spices, and go to the excellent sound guy’s primary effect – EQ – before immediately trying to fix a lame track with layers of fancy plug-ins. Learn the EQ spectrum and work with it often.
Bounce down your MIDI tracks to audio tracks. Yes – this means recording them in real-time internally. It saves processing power at your mix down, among other things. Processing glitches and digital hiccups are not your friend at mixdown or bounce to disc time. Keep the MIDI tracks, but turn them off so you can change the patches later if you feel like it. Experiment with bouncing plug-in settings at the same time for even more streamlining.
Experiment with NOT using the Bounce to Disc function in your DAW. Instead, route a stereo master and record your final mix in REALTIME to a new stereo track. Export that track out instead of a bounced stereo mix. Try using a separate mastering/sweetening program to do the actual dither to 16 bit instead of the one in your DAW.
Even better – if you’re doing a full album for release – run your master out to an external high quality recorder of some kind or directly to your mastering engineer’s system in REALTIME. This used to be standard practice when digital first entered the fray for a reason – it guarantees the integrity of your final mix.
Experiment with listening to your final mixes in lots of different environments. Bounce down in different ways, even trying things like bypassing the master channel of your DAW. Don’t be afraid to try things that aren’t in the manual.
So…get in there and get your hands dirty if you want to fight off the bit depth monster.
Nobody ever said recording was for wusses.