Originally Posted by
JeffW
Always made me wonder on compression drivers. The 2451, for example, is listed as "negative" - but the diaphragms for those are physically compatible with drivers not listed as "negative", and the coated versions of the 2451 diaphragm are popular today as replacements for other 4" drivers. And what about TruExtent? Their 4" diaphragms are listed to work in most all 4" JBL drivers, ones JBL lists as both "positive" and "negative".
Most guys here will be able to do measurements to see if a driver is suddenly out of phase after a diaphragm swap, but looks to me like a potential source of confusion.