The idea that repeat Klaus Fenner, is that above 125 cm the treble begin to suffer from a too large and too heavy panel.
Now Yamaha panels are light generally speaking so they may be less sensitive to that problem.
For Fenner, above a certain surface and mass, counter measures are necessary to obtain good treble, (added inner stress to provide an energy reserve for the treble and have the panel acting as it it was lighter)
there is certainly a less sparkling treble (more sounding toward fundamental than with much high partials) in the taller uprights, when one think of it.
Longer basses are powerful and have much presence, they reinforce the mediums as well.
That is also the effect I had with epoxy impregnation of a panel I did. the treble was stronger, but vulgar, missing partials and life.
I cannot say much about those taller models but the seri have good reputation generally speaking. I just suggest to be aware that extra tallness may provide some problems (action wise too) so keeping that in mind when comparing the different models may be a good idea.
For instance I worked on a very tall Steingraeber. The touch was somewhat "slow", may be due to the tall capstan located on the line of centers at rest.
Interesting touch but "linear" not "springy".
Edited by Olek (07/06/13 04:21 AM)