? about coverting L100T to T3

Decided months ago that I need to try out a set of L100T's. Given all the talk about how they set the bar for rock speakers, I have to know what the fuss is all about. Besides, they're JBL, an American icon in the music industry....and I dig that kind of stuff.

I've been holding out for a set of T3's rather than the T's since, as we all know, the improved crossover design makes for a better sounding speaker. Well, I've run out of patience for a set of T3's to show up on the local market. It doesnt' help that I've seen more than a few sets of very nice T's come and go while I sit patiently (with veins popping out of my head) watching the opportunties to own some very nice T's pass me by. Well, another set of T's has shown up on the local market for $300 delivered and money back if I don't like how they sound. They were recently refoamed (by a reputable local speaker repair service) and the cabinets are an 8 with perfect grills (except a few broken tabs). Yeah, I think I'm done with waiting for some T3's to come along.

Question is, how difficult is it to modify the T's crossover to T3 specs? I have a local source to do this for me (Doug at DC Audio...he's on AK a lot and definitely knows his stuff) and I'd be asking him this question but he is unavailable for the next several days and I need to make a decision soon on these T's. And is that all I'd have to do to get the T's to sound like T3's? Seems like I may have read there was some additional bracing in the T3's as well.

It is not that tough. They sound better when they are done. I also like reducing the cabinet tuning a little too...

Here's the parts required:

L100T L100T3
R1 39 41 Woofer
R2 2.4 2.4 Mid
R3 20 20
R4 1.2 2.4 Tweeter
R5 20 20

C1 40 44 Woofer
C2 0.01 0.01
C3 17 15 Mid
C4 0.01 0.01
C5 14 14
C6 0.01 0.01
C7 3 4 Tweeter
C8 0.1 0.01

L1 3 3.2 Woofer
L2 0.5 0.6 Mid
L3 1 1
L4 0.2 0.2

In the woofer section, L1 goes from 3 to 3.2mH, C1 from 40 to 44uF, and the R goes from 39 to 41 ohm (via 2x82ohm in parallel)

In the mid, C3 goes 17 to 15uF, L2 0.5->0.6mH

In the tweet, C7 goes 3 to 4uF, and R4 goes 1.2 to 2.4ohm.

I believe the above to be correct, but it has been a while and these were my notes from the process.

Very nice, Cosmos. Thank you! Could you elaborate on "reducing the cabinet tuning", please.

You can lower the cabinet tuning by either making the port longer or smaller. There is a concern if it is made too small you could get wind noise, but it would likely be too low if you went that far anyway.. So you can take some paper or flat cardboard stock (like the back of a legal pad) and coil it into the port ID... extending the port with the cardboard. Do so listening and tweaking a little at a time. Some rooms may want more than others. As you go lower, the bass should appear to be smoother, tighter and have less boom. Do so to your liking.