Rear Sound bar Vibration making speakers weak?

i have a 99 XJ with a built in soundbar.
i replaced the speakers in them with a set of 6.5 JBL's
yet even with the new ones they still sound very weak (no bass)
the front ones sound way better.
what i was thinking was that this is caused because the sound bar is flexible
causing it to absorb the speakers vibrations
i was wondering if anyone else has had this problem,
and what they did to fix/improve it?

thanks
-chris mandich

in my experience the sound bars suck in comparison to the speakers being in the hatch. i've had both and hatch sounds way better. better bass, i think because more air room and lit may be sealed better, less flex if that makes sense?

subwoofer

IF you put crap in your cargo area, the hatch speakers will be covered up.

Speaker bar is fine. Try adjusting the bass on your head unit. Are you using the stock head unit as well?

no, i put a JVC KD-HDR1 head unit

and i'm putting subs in tomorrow,
but that'll just make it thump.
i still need those back speakers to be able to get the lows along with the highs.

and i've had 4 xj's
2 with speaker bars and 2 with them in the hatch.
and both with the speaker bars even with new head units
and good speakers, you turn the bass up it just sounds bad

i'm thinking about amplifying the speakers,
but i'm hesitant, b.c of the money
and i'm not positive if it'll help much.

i'm not sure if there's room in the 99 xj for speakers in the hatch.

you said your putting in subs tomorrow i assume there amplified if not your wasting your time/money get a amp with a crossover to power both sub and speakers

you can tune the sub to do more than just hit hard. My twelve adds a whole range to the other speakers and sounds great. Mess with the frequency and power controls on the amp. you can also double check and make sure one of the speakers did not get hooked up backwards. That would cancel out the other speaker pretty well at higher volumes.

That is a fun trick on people running 2 subs, reverse the wiring on one of them. It will cause it to hit exactly opposite of its mate and no bass will occur. Wont do any damage though.

I have a sound bar that I swapped into my trail jeep with 2 speakers in it and it sounds great...

In my fathers 01 cherokee I recently replaced the headunit and the speakers. We removed the oem tape deck and got an oem tape/cd player off of ebay. He had the standard stereo not the fancy infinity one. I replaced the speakers with infinity references. Standard size in the sound bar and 6 1/2" in the front door. The front door speakers have tons of bass and sound awesome but the sound bar speakers seem to produce very little bass and really only fill in the highs. Its a very noticeable difference.

Its rather annoying. The new infinity speakers are also 2 ohm as opposed to 4 ohm so I am not too sure that the headunit likes that as sometimes it gets overloaded and cuts out. But I paid store cost for the speakers which ended up being under $100 for both pairs, well worth it.

Answer to the problem was a small self powered sub in the rear. Sounds a thousand times betters.

Go to the your local fabric store and get a bag of polyfill they use for pilows and quilts . Pull the speakers and stuff the sound bar full and reinstall the speakers.

You can also install some bass blockers on each of the speakers, check Best Buy or a stereo shop for those.

yeah i have an amp for them to

I can answer this one easy. I used to work at Audio Express for a number of years installing stuff and I ran my own audio company that did custom stuff. And yes, my championship sound vehicle from MTX makes me kinda knowlegable.
The sound bar is fine if you get speakers that are meant to be installed in an open air environment. Most speakers offered at most stores require a bit of baffling to produce the advertised sound. Pyramid used to make a baffle attachment just for the XJ sound bar. There are a few cheap tricks you can do to 'adjust' the output of the speakers you without resorting to electronic means (screwing with the EQ or other annoying settings)
The material that xjjeepthing showed you is great stuff for the speakers in the $20 to $80 price range (I used price range since that groups alot of the same speaker offerings to an area of sameness in sound reproduction)
My old favorite, which works wonders if done right (hard to mess up) is to 'seal' the speaker. Take the speaker cage and find a 2 liter plastic bottle. cut the bottle so as to use the bottom end as a baffle and duct tape that sucker on there making sure that you totally enclose the rear of the speaker air tight (as much as possible) cut a 1/2" hole in the rear of your new baffle. Viola! you now have a new 'tuned' speaker, which will produce a more fuller sound. If you made it right it wil barely fit inside your sound bar (cut into ceiling if you like to get more room).
I used to do all kinds of stuff like that for my buddies in highschool who could not afford the serious stuff but wanted better sound. Messing with the EQ's in on your deck will only frustrate you, since the music that is pumped off a CD or the radio is designed for your system to be in a flat state (mid level for each of the ranges) since that is what the majority of consumers have there system set to (default settings).