Wednesday, September 9, 2015

The pseudo-science of digital audio recording

It wasn't so long ago that digital recording didn't exist or wasn't accessible at all to anyone with any conservative budget. Because it's so new, it should've been a red flag to me to see so much "expertise" in the area of advice to young "recording engineers" (of which I've been) and I should've done a bit more research into the history of the art-form before jumping right in. I started recording music in 2001 or so and I started digitally. My first recording device was a Fostex MR-8 Digital Multitracker. Only last year did I ever experiment with using analog tape to record live music and the experience has changed my approach, to say the least. Not because it sounds "better"... but because the way you get signals to tape (or in the case of digital, hard-drive) is, in my opinion, overlooked.

Let me elaborate... When you record to tape the audio signal needs to live on the physical magnetic tape, whereas with digital the signal is converted to digital information (i.e. 0s and 1s) and this difference has an effect on how you should be recording. Now, the size (width) of the tape is finite and so is the size of the digital storage space, but the sizes are different.

The big mistake I was making was that if you read any beginners guide to recording they tell you this: Get the loudest signal you can get without going into the red (clipping) for each component of your music, then once it's all recorded, go back and "mix" your audio and adjust the volumes. I blindly followed this advice for years but now, I don't anymore and this is why...

When you record to tape, if the signal is too hot you will achieve tape "saturation" which is generally an unpleasant sound of distortion, but before hitting this "point of no return" you will hear the tape gladly accepting the signal and letting it fill out all of the space it is alotted: generally this is what's referred to as "warmth," i.e. natural tape-based signal compression. Now the physical size (i.e. width) of the tape is only 2 inches or less, so it's generally a small space to live. I think the idea of capturing  the most digital info as possible in terms of the various components to a mix is mis-guided, almost by definition. This is because the point isn't to hoard all the sonic information just because you can, the point is to record the sound you want to hear on playback. The luxury of "unlimited tape" blinded the neophyte digital recordists ability to properly engineer mixes. The analog workflow has proven to be essential to a natural sounding recording. When you dive deeper into this subject it becomes a combination of philosophical decisions and assessment of history, but ultimately it's about one thing... what sounds good?

Of course we aren't taught this concept of commitment and technique to recreate analog warmth on a digital audio capturing device when it comes to digital recording expert advice and that's where my issue is. If you apply this strategy of get-the-loudest-signals-you-can-without-clipping-and-then-adjust-in-mixing to your digital recording, you'll make a recording where it will come out sounding not necessarily over-saturated, but somehow wrong. It's too many hot signals competing with one another... and only one or two break through at a time. It's a lot for the ear to handle. The processing power of digital recording is mis-used in this context and the results are less than good typically. At long last, clarity?

So how do you achieve tape warmth on a digital recording interface? Change the way you take in audio signals. Just take in the signal at the volume it will be heard at in the mix (i.e. an appropriate and accurate reproduction of what you're actually hearing in the room) and don't go as high as the red, don't even go as high as the yellow. Don't have to adjust any volume knobs at all in your DAW. They should all always be at zero. I personally record to peak signals somewhere between -24dB and -12dB depending on the instrument. I assess this input level as I mostly focus on what I'm hearing through the monitors. If you're using a mixer, put your faders all just below 0 and adjust your input signal volumes with gain (and EQ) only. Your results will be better because you are following an analog workflow for your digital session, and the unity gain simulates the concept of natural tape compression in that it limits the input depth? Something like that... I'm still working on articulating this properly.

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