Altec 291-16L diapragms (21531 and 25885)

[Tom Bellinger]

Thanks Murray,

Given our application we really should be replacing the diaphragms annually. Since we use the drivers as both transmit and recieve, we notice that over time the diaphragm seems to "move or bounce" a little longer after each pulse. This is noticable in our data that we obtain, especially when it gets below freezing outside. We have had numerous diaphragms fail over the past 12 years. I think about 12 or so. I have been running in the fly till failure mode for some time now since our stock of 21531 diaphragms is just about nil. I'm going up to our site tomorrow to take inventory of what we have in stock. I know we have many used 21531's and several 25885's diaphragms. I'll get back to you about getting some 21531's. How many would you be willing to sell?

[Tom Bellinger]

Gasket is in place on the exit. I do/did have a small gap in the driver cover gasket. It did not seem to affect the old diaphragm just the replacement. In the future, if I lose or damage a gasket, can one be made from gasket material from a hardware store providing it's roughly the same thickness?

Something else that I have not fanally reloved:
I going to check how both wires are connected inside all 3 drivers I have. Is this a possible problem? The manufacturer says it should not make a diff.

[Jim D]

With all the banter back and forth, I wonder if one simple, though not always thought of by people not familiar with Large format Altec Drivers, thing may have happened here. Is the round rubber ring gasket in place on the driver exit? It often is not adhered to the driver and when the driver is removed, it falls out. The person reinstallaing the driver, oftimes not the one who removed it, has no clue it exists. Lack of this gasket will destroy diaphragms. We had the local parks crew remove and reinstall a 290 from a horn in a light tower renovation and they forgot to put the ring gasket back in. The driver failed in less than one week. You seem to have been very careful, however please check this. We also have one brand new 21531 diaphragm if you are interested. Jim