Registers, Shifters, Couplers

[Chickers]

I generally refer to bass and treble voice changes as "registers", however, I also hear the term shifters, rockers, and couplers.
Can you help me to better understand these terms, their differences, and how the function ?
Thanks for your comments.
CHICKERS

 

[JeffJetton]

Speaking only for myself, I use "register" to refer to a particular reed configuration. A register is a state that the accordion is in.

I would use the terms "shifter", "rocker", and "coupler" to refer to the physical part on the accordion that you use to select a register. Actually, I most-commonly call them "register switches".

That is, I use my accordions register switches to select a particular register to play in.

Which often causes my wife's face to register an expression of dismay.

 

[Ventura]

rockers were a specific type of "shift" used just before and slightly after WW2

there would be one rocker for one set of reeds

pressing the rocker added the associated reedset
pressing it again silenced that reedset

so you controlled each reedset separately and independently

eventually Charles Nunzio suggested to Settimo Soprani the idea of "shifts" being pre-set to both open or close several reedbanks at once, and the modern system was basically born from that thought, and early empiric experiments to make it a reality eventually codified into a more or less uniform system we see today

 

[JIM D.]

n.wikipedia.org/wiki/Accordion_reed_ranks_and_switches

 

[Alan Sharkis]

Re: the master bar — it may also be referred to as the palm switch or the bump switch.