Two Christmases ago, I was gifted a Hammond SK1 stage keyboard. I remember wanting a Hammond since my youth but no longer have the space (or budget) for a restored Hammond A, B, or C electromechanical tone wheel model or its modern digital equivalent. This unexpected gift thus delighted me.

It also immediately confused me because in my initial fooling around, neither middle C nor concert A sounded right. I then discovered that what I thought was concert A (aka A4) was not at 440Hz but an octave higher, at 220Hz (I've got an electronic chromatic tuner).

What?

This is when I learned about scientific pitch and, more importantly, scientific pitch notation (SPN). Actually, that's not quite true. I knew about SPN from my piano studies long ago, which is why I know that middle C is called C4. The important factor here is that the numbering is based upon the C note. Thus, the lowest C on a conventional 88-key piano is C1. (To add a bit of confusion, note that pianos also have A0 and B0 notes, just below C1.)

Then the Musical Instrument Digital Interface (MIDI) came along in 1983. MIDI does not define octave numbers, only note numbers (from 0 to 127). In 1991, an update to the spec codified concert A (A4 or A440) as note 69, making middle C note 60.

When considering groups, humans tend to number the groups starting at 1. Engineers often number starting at 0. And so it was with the Japanese companies jumping into the electronic keyboard market. Although Roland defined MIDI note 60 as C4, Yamaha, Korg, and later Suzuki (aka Hammond) defined it as C3.

The Hammond SK1 has a "Split point," at which a different sound can be specified for the lower and upper parts. The SK1 Reference Guide states that "C3 is the default Split point." That happens to be between middle C and the B key just below it.

Well, at least I'm no longer confused.

Hammond might be, though. The manual for the Model XK-7/7D refers to the bass range of pedals as 1C to 3C. At least it didn't say 0C to 2C.