Peerless HDS Exclusive - consistency

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Are there any differences between current version of Peerless HDS (8", 7", 5", 1") and the one Zaph tested? He suggests there may be so. I have seen pictures of old Peerless stock and new Tymphany and there was clearly different paper surface, but no measurement was made. I could stand the paper difference, but what about the motor design? Is the impedance curve still the same (good)? I would like to build my new louspeakers on HDS line...

Carefull buying HDS Exclusives, Tymphany has been revising and changing them. I can't say that if you bought this speaker today, that these measurements would be representative.

[john k...]

I can only speak to the 6 1/2" HDS. Initial Qc was variable as the first units were from Denmark. Production moved the China with problems. Latest units appear very consistent.

P.S. All drivers undergo changes. The SEAS Excel units availble today are not even specked the same as thouse of a couple of years back, but no model number change at all. The new Excel using look and spec differently.

[Svante]

I suppose one would expect a serious driver manufacturer to make new measurements and give the new driver a new model number or "mkII" or similar. Otherwise the measurements are nothing but advertisment.

I have six 830870 units that behave VERY different from the original Peerless drivers with two huge resonances (+10 dB) at 6 and 11 kHz. These are not present in the measurements on the Tympany page.

...the bottom line here is that one cannot trust the measurements on the Tympany page.

[rjb]

Don't forget also that measurements of units straight out of the box are not reliable. Drivers vary, but running in is an absolute must, as I found to my cost with some Seas L12.

[Dave Bullet]

Drivers vary, but running in is an absolute must

To see if your drivers have manufacturing faults or amplitude or impedance variations, I'd agree. But for box design, I've found T/S param changes still yield similar alignment slopes.

David.

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I fear disappearing copper most. If could someone post measured impedance curve, it would be still flat, then i would be happy.
My only hope is, that they still write about rich utilizing copper and show flat impedance curve on web.

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Why Zaph writes, that they are discontinued?
I'm going to order them in few days. Do they have rear vented magnetic strucure (hole i centerpolepiece)? I'm thinking about making them coaxial with some small neo tweeter...