Shared Reed chamber in General Concertina Discussion Posted August 30 20 minutes ago, Sprunghub said: I once had a German made box distributed by Campbells, I think from the early 1900's, .....one has been discussed previously on C.Net...... with a "slide" mechanism by the thumb, which created a single or dual reed effect on all the buttons. It was a melodeon reeded instrument rather than traditional, but the effect was the same...."Celestial" ?? or some such branded ? I now own the one described above. Celestial means double reed tremolo tuning according to the Dan Warroll's article here.