Hi there. Perhaps you could give us a little more information. A floor plan of the
existing room layout would be very helpful especially as the location of existing
windows/doors/services will dictate certain elements of the proposed layout. Also consider
how necessary a waiting room is, as personally I would be more inclined to allow for small
storage and machine rooms before a waiting room. Remember, depending on the existing
construction you will need to consider isolation from the outside world and vice versa in
addition to acoustic treatment (not to be confused). The fabrication required will eat
into the overall volume of the remaining space.
I can thoroughly recommend
visiting
John L
Sayers Recording Studio Design Forum and also getting yourself a copy of
Rod Gervais's book. I found it invaluable when building my place
of a similar size to yours.
Read that book! Ask loads of questions on here and
also on RSD forum but make sure you give us the info required to give you a proper answer
otherwise you might find that the responses aren't particularly helpful.
Hope
that helps.