(Originally posted on The Steel Guitar Forum discussion, copied to here.)
Electronic tuners didn’t exist in the 60s. Everyone tuned by ear. The better your ear, the more in tune you were. Before I got an electronic tuner in the mid-70s, I tuned by ear using harmonics. That is what we refer to as “just intonation” (JI). Tuning everything to the center mark on a tuner is “equal temperament” (ET). Most steel players use JI or something close to it, with the pedaled “A” note tuned to 440 Hz (cycles per second).
When I was tuning by harmonics, I started by tuning the E note to a tuning fork. Back then, “Give me an E” was a very common phrase on the bandstand. Everyone tuned by ear. Some weekend bands sounded really bad because of it. Singers were notoriously bad at tuning their rhythm guitars.
The first affordable electronic tuners appeared in the mid 70s. The very popular Korg tuner had a dial to set the note you were tuning and a meter that was calibrated in Hz, not cents, with 440 Hz at the center mark. That’s how the notion of “tuning E’s to 440” got started. In fact, when you tuned the E’s to 440 on the dial, you were actually tuning them to 329.6 Hz. “A” is the only note that is 440 Hz. It’s used as a reference in the same way that “Give me an E” was used in the past. All of the other notes are derived mathematically from it.*
If you are happy playing along to records with ET tuning, there’s no compelling reason to change. Most of us prefer a “sweeter” temperament or JI, but both ET and JI sound in tune to most listeners. It’s not a huge difference. To me, the fact that a pedal steel can sound better than ET is a fundamental characteristic of the instrument. I love it for that. What a marvelous invention it is!
*In ET, each half-step is calculated by multiplying the previous one by 21/2, which results in 12 equal steps per octave. In JI, musical intervals are calculated by ratios of whole numbers. You can read about that here.