Tuning possibilities

Hello,I have recently bought a Boston grand 8 yrs
old.the middle range of keys have the strongest
resonance,can that be modified when I have it tuned?
i believe it has been tuned to concert pitch before I
got it.thanks for any advice

Demonstrate to your piano technician what you are hearing in the middle range, and explain to him/her what you don't like about it so that you're both on the same page. The piano will have to be tuned and regulated before it can be voiced.
It's very likely the hammers in the mid range have hardened (the felt compacted) more than the others due to more use. Keys at the top and bottom of most pianos usually don't get played as often. Voicing will help.
All pianos are tuned to concert pitch (A440Hz). A440 means the A above middle C is vibrating at 440 cycles/second. (Cycles per second are expressed in hertz, or Hz.) This has nothing to do with the variations in resonance you're hearing.

Thank you for explaining how to correct the
resonance,I live in France, & bought the piano
from Scotland without hearing it.Have read
that the Boston has a powerful sound.but although
the piano looks new,the felts could have hardened.
Will speak to the tuner,& am grateful for your help.