DiyMobileAudio.com Car Stereo Forum banner

1 - 1 of 1 Posts

·
Registered
Joined
·
997 Posts
Discussion Starter #1
Just received my Infinity 122.7W 12" drivers today.

Published specs vs measured (WT3) specs:
(parameter : published / measured):
Re : 1.00 ohms / 1.03 ohms
Le : 0.76 mH / 0.50 mH
Vas : 3.47 cu.ft. / 3.767 cu.ft.
Fs : 20.6 Hz / 18.8 Hz
Qms : 7.35 / 6.26
Qes : 0.49 / 0.49 !!
Qts : 0.456 / 0.457 !!


Compare to specs for the eD 13Kv.2-D4 I purchased some time back when eD was having a sale on them
(parameter : published / measured):
Re : 3.7 Ohms / 1.64 Ohms (likely published specs for D2, not D4)
Le : ?? / 0.66 mH
Vas : 5.72 cu.ft. / 2.82 cu.ft. ???
Fs : 21.5 Hz / 27.6 Hz ???
Qms : 3.33 / 5.44
Qes : 0.35 / 0.64 ???
Qts : 0.31 / 0.57 ???


Of course the Infinity 122.7Ws have some other issues that I'm not particularly happy about (I have to keep reminding myself that they were just under $100 each, LOL), but it's nice to know that at least the published t/s parameters can be trusted.

My experience with the eD driver is one of the reasons why I almost always suggest MEASURING the t/s parameters first before committing to a particular box size / tuning recommended by WinISD or another box design program. Take a chance that the published specs are the actual ones, and you might end up with a "Garbage In - Garbage Out" scenario. The published specs for JBL and Infinity drivers seem to be reasonably accurate though to take the chance.

As for how the Infinity 122.7Ws sound, well, I'm going to find out very shortly :)

A few manufacturers publish "birth papers" for their amplifiers, indicating actual measured output capability and s/n ratio, amongst other things. It's a pity no-one (I know) seems to be doing that for subwoofer drivers (takes about 2 min to do with WT3 (excluding Vas)).
 
1 - 1 of 1 Posts
Top