Why do non-modern-classical instruments and players sometimes sound much better than modern classical instruments and players?
Not always, but sometimes.
And this despite accepting - as I do - that great classical players, singers and instruments are supreme in their field.
Why does a jazz clarinet player like Acker Bilk or Monty Sunshine make a nicer sound than any classical clarinet player?
For that matter, why do some early clarinets from the 18th-19th century, make a nicer sound (at their best) than modern ones?
Why do jazz and blues sax players (from Paul Desmond to King Curtis) sound so much better than classical sax players?
Why are trumpets used in modern classical orchestras when cornets sound better, and were generally used in the 19th century?
Why were keyed conical brass instruments (ophecleide etc) dropped from the classical orchestra during the late 19th century and replaced with valved cylindrical brass instruments (trombone, tuba etc)?
The answer is pretty straightforward - a compromise with other priorities.
In the end you get what (poet) Philip Larkin complained about in modern jazz compared with the old stuff - the old jazzers treated the instrument as a human voice; modern jazzers treat the human voice as an instrument.
It is to do with the professionalization of music, especially of composition.
Non-classical players strive for tone, above all.
In pursuit of this they will transpose into the most favourable key, rewrite, and do whatever necessary to achieve their goal.
Classical musicians strive for even-ness of technique - for equal facility in all keys, dynamics and registers, for smoothness of transition between registers, for effortless facility across all types and styles.
Therefore their tone in any given register, key or dynamic is always somewhat sub-optimal.
Early clarinets sounded great in certain keys and registers - but had uneven tone in other keys and registers. Cornets are beautiful in the low register but change quality as they get higher, have a smaller range than trumpets, and are rather breathy on high notes. Keyed brass instruments sound great on their best notes, but tend to change tone and volume on certain notes.
It is the same story as even/ equal temperament tuning for keyboards - equal temperament sound equally acceptable/ quite-good in all keys - but other tuning methods are better for their best keys.
In other words, classical music has continually taken the path of even-ness. Better to be 85 % across all the keys and registers than 100 percent in some and 70 percent in others.
The tenor voice provides a good example.
Up to the mid 19th century the classical tenor sang in (at least) two registers - a high baritone chest voice, and a falsetto flavoured head voice - and there was a break in between these registers.
A really great tenor would sound really great in both of these registers, but each register sounded quite different.
However, this style of singing limited the composers freedom to write musical phrases which crossed between registers - since it would sound peculiar to change register in the middle of a phrase.
So modern tenors evolved, who took the chest voice register right up to high C, which was also very loud and exciting - at the cost of considerable strain, reduced ability to sing a high tessitura, loss of some top notes, and in general a less beautiful tone.
All notes sound similar to the note next-door, but some of the notes are not as beautiful as they could be if even-ness was not a priority.
Something similar happened in male altos - which (probably) were people with a bass chest voice, and therefore a low break in the voice where it would switch to falsetto; who sang most of the time in head voice, falsetto - but dropped into chest voice for the lowest notes.
This was fine for choral singing, but no good for solo work.
Until Alfred Deller discovered how to stay in falsetto even for the lowest notes while still being audible. However, while acceptable - the lower notes were still quiet and sub-optimal.
Another innovation was the high tenor/ tenoraltino (Russel Oberlin, Rogers Covey Crump) who sang alto by extending the tenor range upwards into falsetto, learning how to blend the chest and head registers to disguise the break in the voice.
However, this is very difficult, very rare, and insufficiently nimble across the break for routine choral work.
My point behind all this is to note the fatal error which classical music made in compromising with beauty.
Voices and instruments sacrificed beauty of tone in favour of other imperatives.
The composers did the same.
In the end (from Stravinsky and Schoenberg onwards) classical composers were composing music that was not beautiful at all - indeed it was not even trying to be beautiful.
Most recent classical music - far from being beautiful - is actively unpleasant; we are supposed to appreciate its other qualities, but not its beauty.
So we find ourselves in a situation where art - which originally broke away from morality in order to pursue beauty untrammeled by religious acceptability (art for art's sake; i.e. aesthetics indifferent to morality) - ended-up by being not-beautiful-at-all!
In this we see an exact analogy for the situation in natural science - which broke away from theology (and then from philosophy) in order to pursue truth without regard for morality; and ended up being not-truthful-at-all - not even trying to be truthful.
Note: To understand what I mean listen to the sax playing on this:
It is best to listen from the beginning, but if you can't bear to do so the sax solo comes in after 2.35 - and is the best I have ever heard, bar none.
Notice that the tone is incredibly "un-even" - no classical player could or would do this. The player is Wesley McGoogan - a virtual unknown except for this glorious few minutes of work.