Question about my L100T's

[Boss96]

I got them home tonight after listening to them at work for a day or so. At home I have a Pioneer surround receiver, a fairly powerful one, a little over 100wpc.
Anyway, I was trying them out and was playing them fairly loud and I bottomed out the woofers..I had read the spec sheet for these speakers and understood you could use them with an amp up to 400 watts (probably an exagerration). I had looked at one of the woofers (a 2214?) 3" voice coil, big magnet, etc, and figured with my measly 100watts I would not cause these woofers any trouble.
Later on I pushed the cone in to see how far it would go and it went about 1/4" in and then bottomed, I could hear the voice coil hit. Is this normal for this vintage speaker?
My previous speakers (homemade with Rockford Fosgate 12") had more excursion than these and were nowhere near as well made as the 2214's.
Is this normal?
Bob

[Robh3606]

Hello Bob

First thing is don't make a habit of moving the cones by hand. They don't have all that much clearance. I use the same woofers with strapped Crown PS-200's which is about 300+ clean watts and have never had them bottom out on music. Where you in HT mode or music?? You have any bass boost in place?? Turntable up and running?? Any powerful low bass below box tuning on a reflex cabinet is a potential problem.

Rob

[Boss96]

Well, I hate to admit it but I had the bass turned up fairly high and also some EQ in the low end to get the sound I was looking for. I'm aware of bass reflex tuning and the problems of sending it a signal lower than the port tuning but I was still surprised it happened. My old speakers were bass reflex also but had no problems.
FWIW, I was listening to the Who's "Won't get fooled again" which has a pretty good low note or two near the end of the song and this is where it happened. Also tried some Steely Dan, the latest CD's which have very good bass and it happened on them too.
Unfortunately the room I am using them in is not optimum at all, the speakers are in a corner caty corner (sp) separated by a TV.
I just can't imagine JBL rating them for use with 200 wpc amps and not thinking someone may turn up the bass control
However, if that is the way they are then I can live with them.
Bob

[Robh3606]

Hello Bob

I hear you but you have to realize that for every 6DB of bass boost you increase the power by a factor of 4. With 10 db it is 10X. With that in mind if you are cruising at 10 watts which would be loud with them and 100 watts power for your amp you have 4db of headroom before your amp clips at the frequencies where the bass boost is applied. With 10db of boost you have none assuming no headroom. Bass boost just eats your headroom. If you like the bass up a bit can you get them into the corners or closer to the sidewalls?? That would give you more bass without the electronic boost and give you more headroom. Might help things a bit.

Rob

[Boss96]

Thanks, Rob, I'll probably have to convince the wife to change the room around some
I certainly understand the headroom problem, in fact I am looking for a bigger amp now that I have these speakers but after seeing the woofers bottom out I'm wondering if that is a good idea. I know I can get the current receiver to clip fairly easily with lots of bass but that won't make a cone bottom out, just get muddy.
Oh well, I'll see if I can move them around somehow and find the perfect spot to sit in too
One thing I do like about them a lot is the mids and highs. Quite a bit different than what I had before, seems to make most music "clearer" although I suppose that can be caused by a rising mid or high end too.
Bob

[Zilch]

2214H Xmax = 6.60mm = 0.2598"

Check for DC offset comin' outta that amp.

Does the cone move to a new position when you turn the amp on?

[GordonW]

X-max and maximum mechanical excursion are two different things! While a 2214 has about a 1/4" X-max, it should be able to move inward close to 1/2", before bottoming!

I'm guessing maybe there is some damage to the driver... either a collapsed spider or an improperly installed replacement foam surround (this can happen when someone mistakenly installs a foam surround on the FRONT of a 2214 cone- it's supposed to go on the BACK). These things can significantly off-set the cone inward, making it easy to bottom out.

Regards,
Gordon.

[Boss96]

No DC offset, surrounds are attached behind the cone. Can't verify the condition of the spider other than that they are there
FWIW, they do have a relatively stiff suspension compared to other speakers I have seen but that is very subjective at this point.
I have a feeling that there is nothing wrong with them, perhaps back in 1985 it was'nt considered that important to have a long suspension travel compared to today.
I guess if I really wanted to I could buy a modern JBL 12" driver like the ones they sell for car audio, I'm thinking of the one that looks almost 12" deep That must have some serious suspension travel
I wonder how well it would match up to the current mid and high freq. drivers?
Bob

[Zilch]

I you want more thunderous bass, add a pair of subs. Fully one-third of the content of this forum relates to that subject, probably....