L100A Bastard Speaker

[Martin_Cph_DK]

I have picked up a pair of L100A (serial 296452A/296456A) - they sound sort of OK, but I have feeling that something is wrong around 6-10 kHz. I have been adjusting the presence and brilliance for quite some time but I never really hit it right.

I am worried that I may have a "bastard" speaker...??? Semi/Non original.

It's JBL components all the way and there no signs of malfunctioning. It's like the response proberties are off? As if the components have been changed and no longer fit the original x-over?

They hold the 123A woofer, 104H-2 midrange driver and LE26 tweeter

I am worried that I need the individual response data from all drivers while placed in the cabinet to simulate and make the a hard-wired test crossover to fine-tune the crossover for my listening position....unless you guys tell me differently.

Is this a driver combo that you are used to seeing?

This site rocks by the way - great job!

[grumpy]

http://www.harmanaudio.com/search_br...=US&Region=USA

even the last run appears to have used LE5-2 mid, and LE25, tweeter...
I would -guess- that the midrange would have the largest effect in sounding
different than stock components.

[Zilch]

104H-2 is considered by some as an upgrade to tame down the forward mids of the stock L100. Somebody changed the midrange drivers in yours. First thing I would try is reversing the phase on that driver and/or the tweeter to see if they will integrate better.

There are many, MANY threads here outlining various approaches to making L100s "Right," that being a matter of definition and personal taste. They've been analyzed, upgraded and tweaked to death ever since first produced.

In my experience, they are what they are, which is colored, inaccurate, and fun, and any endeavor to make them be something else is largely pointless.

If you want studio monitors, buy studio monitors. L100s aren't that, and can't be made into that....

[Martin_Cph_DK]

Thanks for all your help.

So the 104H-2 is OK in terms of "fitting" the original x-over. (the phases are right)

What about the LE26 compared to the LE25 - how does this change fit?

Its an extremely simple x-over anyway - maybe I am just seeing (hearing) things or demanding the impossible from this old gal?

I am used to the Dynaudio Special 25's.

If you want a very analytical JBL-monitor what should I opt for?

[Zilch]

If you want a very analytical JBL-monitor what should I opt for?

Now discontinued 4400 series, 4410 or 4412, particularly, quite affordable used, or LSR series, not so affordable....

[Doctor_Electron]

ZILTCH is exactly correct. Several years back, I had a problem in one of my 4410 crosssovers, and in the process of fixing it I wound up rewiring both cabinets and screwing up (reversing) the mid drivers' phase. The sonic result of this was absolutely horrendous. I then suspected that my CD player and/or power amp had gone south. When I finally "pulled my head out", all was well again. I could not believe how bad they sounded, it was really amazing.
I had become complacent and overconfident in that project, after 30+ years in Hi Fi & electronics, in not documenting all the details of what I done. That won't happen again!

[duaneage]

Specifically what happens with phase mis connection is a hole develops in the response between the woofer and the midrange, causing them to sound dull or flat. It also changes the polar response between the mid and tweeter so they only sound proper if tilted extremely back or forward.