Playing Volume - Past and Present
My buddy Pete asked me to discuss how loud pro players play on the harmonica...
In my early years, everyone was playing unmodified Hohner Marine Bands. At that time, the combs were not sealed and the harps weren't set up as well as they are now, so most players played with a lot of force/volume. For those that used Hohner Special 20's, they still played loudly, but slightly less so, due to the consistency of the plastic comb.
Then, when harmonica customizing came around (early 90's), it took players a while to accustom themselves to how much less force they needed to use to play these harmonicas, and many, myself included, destroyed a whole bunch of custom harmonicas in the process until we learned how to dial it down. I still know a few old-school players that have a hard time playing softer, so they'll play modern harmonicas (that play very well), but won't/can't use custom harmonicas.
Now, generally speaking, everyone I know (students and pros combined) play much softer than in the past. Custom harmonicas have mostly to do with this and the fact that current harmonica models, like the Hohner Crossover, play so well out of the box, that there really is no need to play hard on a harmonica any more.
These are good times to be a harmonica player.