What's Up with Digital Audio?

What's all the fuss about digital?
Yeah, what's all the hubub, bub?

Sixteen-bit master recordings are not adequate for subsequent replication on 16-bit CDs.

That is to say, CD quality isn't good enough for CD output.

For example, when using a digital console or workstation to add equalization, change levels or perform other digital signal processing, error accumulates in the 16th bit due to computation. It's one of those bit-twiddly facts computer scientists are paid to discover, and sound engineers go to school to learn about. It is therefore desirable to use a longer word length, such as 20 bits, that allows processing prior to 16-bit storage.

However, the problem of transferring 20 bits to 16 bits is not trivial. Nor can it be avoided, for CDs only work at 16 bits. Simple truncation (chopping-off) of the four least-significant bits greatly increases distortion in the overall output. If the 16th bit is rounded, the improvement is only modest, and distortion still occurs. Noise shaping, dithering and all sorts of techniques have been applied to try to smooth things out, but the solution really lies in a higher bit rate and a combination of mastering techniques.

So Atlas Audioworks starts off with a fat 24-bit-professional-level, super-clean signal, and later squeezes it to fit seductively in a slinky 16-bit outfit that anyone can take home to enjoy. It's all done with outstanding dedicated digital-to-analog and analog-to-digital processors and the latest in professional studio software.

It's all about detail, really. In audio terms, each bit of resolution translates into about 6dB of dynamic range (the difference between the softest and the loudest sounds that can be represented.) A 16-bit CD has has a dynamic range of 96dB; a 20-bit system has a range of 120dB.

Our 24-bit system has a theoretical dynamic range of 144dB. It remains theoretical, because the physics of the real world and limitations of human hearing refuse to let us experiment further.

Something to keep in mind is that the extra dynamic range afforded by higher resolutions isn't on the loud end of the scale, rather the bottom of the scale is pushed down, capturing quiet sounds more accurately.

Digital equipment has been cursed from the start for being "too good," or "too clean" to produce the warm, fat, greasy, vintage-sounding, saturated sounds we've all grown to know and love. That warm, fat, soaked, seductive sound is called distortion. It has many other names, but all boils down to some sort of grungy coloration of the original sound. It also comes at a price--tape hiss, tube hum, and the occasional broken or overdubbed tape and subsequent destroyed masterpiece. (There is no "undo" in the analog world.)

The particular sort of distortion that we appreciate has a certain harmonic quality to it and is dependent upon a variety of different factors. It is true that nothing makes a guitar sound beefy like a hot, overdriven tube. Nothing warms up a voice like valves. Nothing mellows out a signal like tape saturation and a tube compressor. Nothing except painstakingly modeled algorhythms that controllably simulate all of those and more. We use digital reproductions of vintage microphones, preamps, amplifiers and tape machines. We can simulate the sound of vinyl from any era, a speaker cabinet that you wish you owned, and acoustically modeled rooms from shoebox-size to mother-of-all-ampitheaters.

Is it convincing?

You bet it is. We are musicians ourselves, and if it doesn't sound great, we don't want anything to do with it. We can give you all the perks of analog without all the problems. If you still want hiss and crackle when all is said and done, we can add it into the mix. We can even add in motor hum and 60hz noise, if you really want the analog sound.

The dynamic range of tape isn't up to par for CD mastering or archiving. The motion of the tape across the recorder's heads creates noise and hiss. If you need to copy from one tape to another or combine tracks together, you'll add noise and probably lose some treble response...you're compounding the uglies. This is called generation loss. We've all heard it, and we all hate it.

Tape begins to degrade as soon as signal is recorded on it; the magnetic patterns start fading, and could even print from one layer of tape to the next on the reel. Tape is crap.

Don't even consider recording your inspired creations to tape. It has been out of vogue and behind-the-times so long that you should feel a tinge of guilt for even considering putting your precious work on such substandard media. Do you really want to go into your project knowing that there will be hiss and noise from the start? It's time to clean up your act.