The Talking Machine Forum — For All Antique Phonographs & Recordings

I put a note on the Edison site in my "Designing a Diaphragm" thread about some updates I am doing. One thing I think I stumbled across today that I hadn't considered before was having to do with the replacement rubber gaskets.

I had installed a diaphragm I was working with into a different head, one in which the gaskets were the type are are noticeably wider than the originals, most of which are about the size of the metal retaining ring. When I put it on the machine to test I noticed it seemed more lackluster than before. The only difference I knew of was those gaskets. I switched them out for the narrower ones and tried it again. This time the volume level was back up to where I had heard it previously. I would seem that the extra width which does cut down on the area of the diaphragm that can vibrate may cause it to be less responsive and somewhat duller sounding. I know there isn't a lot of difference, but to my ears it was pretty obviously different.

I wonder if any of you have both types and might be able to switch them around and see if you get a similar effect?

The upside of making the switch is that I discovered that the original needle, while exhibiting no defects visibly, evidently is causing the kind of thing to a degree that a steel needle with too many plays will, a sort of fuzzy quality that leaves you feeling the music isn't quite clear. It may be some of the diaphragms I was writing off as faulty were less so than I thought?

While I haven't tried this on my DD reproducer yet I am aware of this issue, especially when doing recorders and floating reproducers. I totally agree with your theory, by the use of a wider gasket the diaphragm's size is reduced which usually results in lower volume and even up to a more squeaky sound.
Especially recorders are very sensitive and I always try to apply as little wax as necessary to hold the diaphragm in place.