Can it be simply put what is the tessitura of an left-hand of a Stradella bass accordion?

Question

I have seen no such chart that's a simple bass clef gliss of what the left of a Stradella accordion plays. I have seen the chart linked in this answer about accordions, but it says nothing of the intervals (which seems like a dumb thing to say, since it's obvious it's fifths going up and fourths going down, but I've watched a video where a player goes strictly up the column of bass notes and some are fifths and some are fourths, and she doesn't even cover the counter-bass buttons). On the topic, are there any gaps in the chromatic scale along one?

Answer 1

There is a very detailed article "Registers of the Standard Stradella Keyboard" by Donald Balestrieri published in 1979 in Accord Magazine, U.S.A., that in very fine detail explains the ranges of the various reed banks and the available combinations. That gives a good idea how a player may utilise their instrument to the best degree for arranging a piece best for fitting Stradella bass.

Contrary to what this article suggests, however, its advice does not apply to more than a single particular instrument model. The number of reed banks, their individual ranges, the available combinations, whether or not bass reeds are coupled into chord reeds: all that differs by instrument (or at least manufacturer) and cannot be depended upon.

Consequently it is much less common for bass registrations to be listed in arrangements of accordion music than it is for the treble: there just is not much to rely on.

Answer 2

It's fifths up and down going up and down, not accounting for the octave. No exception (we are not talking about Belgian bass which is the other way round). Accounting for the octave is not done since each reed bank in the bass covers only a single octave and whatever note in this octave happens to match the desired pitch is played.

It's not even a given that the different reed banks selected by registration have an octave of distance. While big Hohners tend to have reed banks starting at E1, E2, E3, E4, E5, an Excelsior of mine does A1, A2, F♯3, C4, C5 in order to better mask the octave breaks when playing in the Master register: it's the rule rather than the exception that whatever reed banks are used for the chord buttons are also engaged for bass notes while the lowest two reed banks are reserved exclusively for bass notes: the bass couples into the chord reeds.

Some Gola models are examples for accordions foregoing the coupling: in order not to be unbalanced in Master then, they have a third reed bank exclusive to the bass notes.

Answer 3

I haven't heard of any standard for exactly which notes a Stradella bass plays. Each kind of accordion is different and each register switch is different. It often isn't documented for a particular model.

Typically, the chord notes come from an octave range, and the single bass notes also come from an octave range. They might be the same range, but the bass range may be lower than the chord range, depending on the register switch.

Also, sometimes the bass buttons will play octave intervals, blending notes from two octaves together. You can play an ascending scale and keep going without an obvious jump down, sort of like a Shepard tone illusion. As you go up the scale, the top note of the octave interval fades out and a lower octave fades in. (This fools some people more than others.)

If you're curious, one way to find out what's going on for a particular accordion is to use your ear and compare each note with a piano. However, the blending might make it hard to decide which octave interval is being played for a particular button.