So rather than fixing the problem with the sound difference between white and black keys (or really, the sound difference between the two blocks in cassotto)
when Paul explains the physics of these fine points even i (think) i understand !
now on to the less quantifiable reasons..
not just for Jazz, but also players who use their treble like Vocalists use their voice,
we want a really clean, sweet, and pure tone that carries with great dynamics
(as opposed to raw boldness and volume)
and we like that tone to be rich.. more than a solo M or solo L..
but the OPPOSITE of Musette
so our L+L and M+M are tuned in unison, or damn close to it..
some of us, like on my 960, have all 3 M-McM+ reedsets basically tuned unison
(mine is an LMMMH configuration)
AND then there is the touch
we need it to be light and responsive, ridiculously quick, so
you are talking about high-end accordions that are built with dual pivot
rods and walnut bodied keys and hand tweaked balancing and springs
and SHARPLY CUT AND TRIMMED valve pads over the reedblock plate
this also implies an action mechanism that has near zero lateral play,
which goes back to the Pivot not merely being low-friction, but also
being quite robust
when those Jazz players are flying, the keys are barely depressed but
the sound has to still be perfect, so the airflow must be perfect too. Precision,
with that minimal lift of the pad off the hole.. and the buiider/finisher
needs to do this with a split Cassotto keyaction, meaning two points
where the pressure and pads must mate then lift perfectly in an absolute
harmony of motion
so you can say sure, a good accordionist CAN play Jazz on a student LMH,
and they probably can.. for a minit just for giggles and grins.. but when some faker
calls some piece of crap he sorta fixed up a Jazz or Pro accordion on their Reverb listing,
and it doesn't make the grade, people just gonna laugh at him because we know
which ones were built the right way and which ones were not
and those who do not play "Jazz" or need that level of touch, let them play
a real Super6 one time and they will understand what a difference that
level of quality makes.. let them squeeze a real AC one time and they will
never forget what it felt like.. how it almost plays itself..
what is a Jazz accordion ?
simply the best, with the cleanest, purest, sweetest sound imaginable
inspiring to play
rock solid reliable
something you treasure if you are lucky enough to get your hands on one