Yamaha C6 v C7

[amugen]

Here in Thailand the local dealers don’t stock C6 and I will have to wait 6 months if I order one. I have heard many people on this wonderful forum say that there is a big leap between C5 and C6. I have a 28 x 13 room, which opens onto another small room of 5 x 13, ceilings 8ft high. Would the C7 be too loud for such a space? There is only a thousand dollars difference between the cost of the C6 and the C7, yet between the C5 & C6 $4000. I am assuming there must be some greater technical excellence in the C6 & C7? PS Yamaha is the only reasonably priced quality piano here along with Kawai

[amugen]