Three minute reads for audio engineers and music makers

By Thomas Dulin

Hey Reader, here's this week's Take Three email.

TAKE ONE: QUICK LINKS

• I enjoyed this article, "Should Audio Professionals Advertise Their Rates?" by Russ Hughes
• Sony and Warner Chappell have sued Anthropic, via Variety​
• Reason software is now available as a free plugin in your DAW, it's called Reason Free.​

TAKE TWO: PHASELOCK UPDATE

Over the last week I've solved two problems with PhaseLock: one specific to Fender Studio Pro, and one specific to Reaper. Could not have found these issues without the help of amazing beta users. If you want to try PhaseLock for free, join the beta list here.​

We also added group lock, Add To Analysis, Live Sound mode, and a global bypass button so you can A/B your whole session.

I'm planning to release very soon! More info coming.

TAKE THREE: THREE COMMON MYTHS ABOUT PHASE

Phase is the least-understood / most-important-to-understand concept among working audio engineers right now.

For this week's Take Three, I'm going to talk about 3 common misunderstandings and myths around phase that I see talked about all the time.

#1: "Just look at the waveform."

I saw a clip of recent podcast where a guy (a smart, successful engineer!) advises listeners to always make sure that a given waveform starts "up" or positive instead of down, and then just make sure all your waveforms look good visually.

I understand where this comes from, it seems intuitive. But this is a gross misunderstanding of complex waveforms, power amp design, and the human ear.

Too much for this "3 minute read" but if you're curious about this rabbit hole, this research paper is a great starting point. The short version is that you could maybe hear the difference between positive and negative excursion of a simple waveform on headphones in an anaechoic chamber.

Even if it were true that a positive-first waveform was a "good" thing (it's not), you have to account for all the processing that's going to happen downstream of that waveform! A simple high pass filter can easily turn visual upside down.

#2: "Polarity = phase"

This one is super common. If you only have time to think through one of these, choose this one.

The ɸ symbol on a mic preamp inverts polarity. It's a completely linear process, meaning it applies to all frequencies the same. In your DAW, it multiplies every sample by -1 (an inversion) so that what was positive is negative, and what was negative is positive. In isolation, it sounds the exact same (see myth #1 above).

We often invert polarity when we have two signals that are around 180 degrees "out of phase" around an important frequency, meaning one signal is positive at the exact moment the other signal is negative, causing loss of magnitude at that important frequency.

Another way of describing that action is to say that we rotated the phase 180 degrees. Or, we "flipped the phase." These are simple shorthand phrases that describe the action of inverting polarity.

Phase is actually a much broader term, and it does include the concept of polarity. But there are other ways to manipulate the phase relationship between two signals.

We can, for example, use delay. Delaying one of the signals could improve the coherence of an important frequency, but it could also produce comb filtering in another range of frequencies, so that's a trade off. Moving a microphone is a form of delay!

We can also use all-pass filters, which are EQ filters that have no magnitude change -- they only rotate the phase around a specific, important frequency. This can cause "group delay" or "phase smear" which is another tradeoff.

To sum this up - the umbrella known as phase is much larger than just polarity. And there are more ways to control it

#3: "Time alignment = phase coherence"

I've been learning and obsessing over the science behind phase relationships for the last year

Until next week, happy music making, Reader.

Thomas Dulin Producer / Engineer / Mixer