T/S Measurements, Nomex vs. Poly

[ch83575]

Ok, I have measured these drivers (Peerless 6.5" HDS Poly & Nomex cones) a few times now, both with an 8ohm resistor and 330ohm resistor and I get measurements that are pretty close to spec (at least for the Nomex), but not very close to each other (not close enough for me to be confident that is, specificaly the VAS). I dont understand how for each driver the constant current technique would produce different results than and 8ohm resistor. I have repeated the measurement process with each technique and each result is repeatable, but not matching. My question is which should I use? Am I worried about differences that are not very big on the grand scheme? I am doing these at low levels, with broken in drivers and using the added mass technique.

Here is the two techniques for the Nomex:

8 ohm resistor:


constant current:



And here are the measurements for the Poly cone:

8 ohm resistor


constant current


The other thing that I am worried about is the Poly cone is pretty far from the spec. It would not normaly bother me, but Peerless seems to think they are almost identical, and I get results that are pretty different for the two cone materials. Has anybody else had this experience? Should I suspect my measurements, or do the look reasonable?

Thanks in advance,
-Chad