Advice on JBL 18Ti Bookshelf speakers

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09-27-2008, 07:51 AM
Jeddyb

Advice on JBL 18Ti Bookshelf speakers

Hey everybody, I'm new here, so, Hello!
Anyway, at the moment I am using a mixture of components for sound.
The main source is my PC, into which I recently installed a Creative Soundblaster Audigy 2 ZS sound card.
The main amp is an older one that my brother built. It is stereo 100w x 100w. Unfortunately that is about all the info on it I have except for the fact that it is a two piece set. One piece is a relatively small main head which has the PCB and is surrounded in heat sinks. Then it connects via a "speakon" or something cable to the power supply which is roughly the size of an average audio receiver and has 4 giant capacitors and a really big toroidal transformer.
The output is my father's old set of JBL 18Ti bookshelf's. Titanium tweeter, 6" woofer, 45hz-27000hz. http://www.audioheritage.org/vbullet...ad.php?t=10622
Very good speakers, although recently I've been having a few problems. I've noticed that in the left one, there is a tiny rattle of some sort. It really is apparent around 1000-2000hz or so. It sounds almost like something could be stuck in the voice coil.
Another thing I've noticed is, despite their supposed ability to withstand up to 200watts, at relatively loud volumes, the midrange becomes worryingly muddy and colored, mainly I would say in the realm of 1k - 3k. You can hear it very clearly with something like the Fur Elise and many piano pieces.
Please, any advice would be greatly appreciated because these are very good speakers. Even now they still retain a very powerful bass, the high are very clear and they sound quite amazing with heavy rock like music, but I really want to be able to enjoy more delicate music at elevated volumes.
09-27-2008, 09:38 AM
4313B

Quote:

Originally Posted by Jeddyb

Another thing I've noticed is, despite their supposed ability to withstand up to 200watts, at relatively loud volumes, the midrange becomes worryingly muddy and colored, mainly I would say in the realm of 1k - 3k. You can hear it very clearly with something like the Fur Elise and many piano pieces.

It is a known liability with that 6.5" polycone.
09-27-2008, 10:59 AM
Jeddyb

I see, do you think getting them reconed would make a difference?
09-30-2008, 10:28 AM
duaneage

I doubt a recone would make a difference if it is a known problem. These are small speakers, 100-200 watts is a bit much for their size.
09-30-2008, 11:22 AM
BMWCCA

As I read it, he's got two problems: 1). a rattle, 2). mid-range mush.

Depending on the problem, the rattle might well be fixed with a re-cone though the 115H-1 may well still be available new from the Pro site for the 4406 monitor, though I don't see it. Regardless, L20Ts with the same LF speaker can be bought for a paltry sum quite frequently. Certainly less than the price of a cone kit.

That being said, I've run my L20Ts pretty darn loud using a 200wpc Crown amp and find the speakers' performance remarkable for the size. Are you sure you're not hobbling your JBLs with whatever program material you're feeding them via your PC? How large a space are you trying to fill?
09-30-2008, 12:23 PM
Robh3606

Quote:

That being said, I've run my L20Ts pretty darn loud using a 200wpc Crown amp and find the speakers' performance remarkable for the size.

I have agree with you, one of my small speaker favorites. Especially when you consider what you can get a pair for. Put a decent sub under them and it's a real hoot!

Rob:)
10-04-2008, 10:23 AM
porschedpm

Quote:

Originally Posted by Jeddyb

...recently I've been having a few problems. I've noticed that in the left one, there is a tiny rattle of some sort....

One of my 18Ti's also had a subtle 'buzz' or rattle as you put it. It wasn't very loud but once you heard it your ear would go right to it whenever that speaker was on. I isolated it to the woofer although I'm not sure if it was a problem with the voice coil since the DCR stil read 4.5. I 'fixed' it by finding a replacement 115H-1 woofer on eBay for $80.
02-26-2010, 10:22 PM
Jeddyb

Hey guys, I know this thread is ancient, but I though I might just say what I did with the speakers in case anyone else has a similar problem and want advice. It seems like the last time one of them was reconed, the guy did a bit of a dodgy job of gluing the cone to the surround and so I simply took it upon myself touch up the those loose areas and they seem to have no problems now.

Also might I just say, oh boy! For a while I've had them going through a highpass filter running along side a sub, but just a couple days ago I took off the filter and let them loose and I was really very surprised at well they can handle themselves, it also gave me a chance to turn the low pass filter on the sub right down to like 60Hz or so and it also sounds so much better not having to deal with all the midbass frequencies.