Dick, I mentioned before that the "steel" itself has been misvalued in many discussions since in the absolutely greatest part major accordion/concertina makers have been using the *same steel* for a century. The tongue *material* has a know importance though and *mostly* steel reeds, iron alloy reeds and brass reeds sound differently but differences may be reduced by processing methods.

No question - as I tried to say - the *free reed* (frame + tongue)in free reed instruments IS the most important factor for sound qualities. This has been evaluated labwise and is supported by massive maker judgements but naturally when instrument makers market their own products they often(always..) try to promote other factors, particularly those they regard as "their own" - sometimes patented substantial qualities,sometimes minor marketing lies etc

You said initially: "what is the most important contributor to acoustics as regards concertinas - is it the steel used for the reeds or the wood that is used in the construction".

As a consequence of what I have said it is in real an impossible question since it is NEITHER the steel NOR the wood! - but IF you insist on one answer it will be this: In principle it firstly is the *free reed* (tongue+frame) qualities - secondly ALL qualities from compartments and materials may be of minor or major importance..but that is not a very meaningful answer either since you learn very little from it. IF we wish to learn something we simply have to check the tests which have been carried out and do some more to get further...