HF driver comparison 23744 vs 34647

[Alien_Shore]

But there's something that should be said for what looks like a 35+ year old diaphragm that is still outperforming a newer one on paper. (Flatter Response)

Two main points to ponder here: a) the "better measuring" transducer is not always perceived as the "better sounding" one, and b) a difference in frequency response between two different transducers is likely only one of several differences in sonic signature.It's not just brand loyalty that drives the Altec enthusiast, the fact they sound so good has a lot to do with it..

So here are a couple of other measurements that are interesting, given your comments. The first is that same 34647 fram in a 908 ferrite driver, compared the 802-8G driver, mounted in the big 511B horn, again measured with all other conditions the same:



And here is the 802-8G with the lite fram compared to a brand new B&C DE250-8 driver (with its own new stock polyimide fram):



One thing to note is that the 23744 lite fram would not play well at all in the 908 driver body. One fram had fairly severe distortion 500-1100 Hz, and the other fram had less distortion but very low output 500-1100 Hz or so. I tried both since I was curious if it was either particular to the one fram, or if perhaps I had mounted it improperly. These tests of course did require me to employ the fram conversion kit, to put the newer 34647 fram into the 802 driver, and the older fram into the newer 908 driver. It was quick and easy, but you need to have that tiny star wrench to remove the binding posts...