lex400sc,

MW is right, I'm only running 2 front speakers and 1 sub. Not 4 speakers. Sorry for not being clear and I realize you are not as involved in this thread before.
I don't think I've gotten bad advice at all. I'm just learning each day and trying to figure this whole 'science' out
I was on the Boston ProSeries site the other day and found out it could handle up to 400W of power ?! With my friend's comment about underpowered, thats why I thought maybe the JL 300/4 might not be enough at high volume.
another newbie question I'd like to throw out there. some of my dissatisfication has to do w/ the way the IB hits. it's thumping and shaking back there and i think it has to do it being so close to the gas tank. Also, you know the rear enclosure from the trunk? Should I by using some insulation there to make the sound better? It seems like the whole bak end is just one rattling mess. I have a feeling thou, that this is something on the SC's that we have to live with.

 

I'm in the same boat as Legend. Two of my stock speakers blew out and now I have an awful buzzing that drives me insane. I would like an upgrade but don't really want an aftermarket deck ruining the "luxury appeal." Can i have a shop wire up two amps and have good sound with the oem headunit and changer? And of course all speakers would be changed and maybe 1 subwoofer in a box would be added. Thanks

 

Try some acoustic damping in the tank cavity, the fibre stuff you get for putting in speaker enclosures to supress standing waves.

 

You mean like some Polyfill in front of the tank? Great idea Bill...

 

Lex,

It has different brand names but that is the stuff, it will help the free air sub and prevent some rattles.

You can never have to much sound proofing, Dynamat is expensive, if you are going to do the whole car then try to get some "torch-on" roof flashing (they use it to replace led flashing on roof joints), it is a bitumen pad, self adhesive and comes in several metre rolls, in the UK it's about £12 a roll, if you use a gas torch to soften it, it then sets quite firm and will stiffen the panels, I also put this on the fuel tank as it generates noise from the bass - DONT USE THE GAS TORCH IN THE CAR !

When I mounted the 8" Rockford Punch in the rear shelf I made an oversize mounting plate in MDF (fibre board) and screwed this down to the shelf to provide a stiffer mount, the result is a better hit from the smaller sub and less rattles.

 

The Lexus would be the perfect car to use acoustic membrane.

 

Bill, for me it's not the cost, it's the weight - i'm on the track more than i'm on IASCA's floor. I use Xtreme Dynamat, but I use it sparingly, only in the areas around the drivers, but it works, I don't have any rattles and the bass is tight and not muddy whatsoever. The acoustic damping fibre though, that's a solid idea, with no weight penalty. Next i'll try a little Deflex action in the doors...

- LL

 

JL Audio 300/4

This amp is not designed for mid/high and sub combo setups. The power rails on channel 1/2 and 3/4 are variable and are determined by the lowest ohm presented to each group. Meaning if you have 4 ohm speakers all around then all get equal power. If you have 4 ohm highs and a 4 ohm sub bridged off 3/4 then you only get 1/2 power to your highs ... so 37.5W RMS per speaker instead of 75W RMS. I would never ever recommend this setup to someone without letting them know this info first. If going with a single sub, then purchase a 8 ohm sub. Even still, the JL designers didn't design this amp to run subs. That is what their monoblock amps are supposed to do.

 

I suspect most "bridgable" 4 channel amps are compromised when 2channels are bridged, specifically when driving a sub.

 

Actually running the amp in bridged mode is not that compromising. Sometimes you can actually get better performance with dampening factor. The reason that JL is different is because of the games they play with their power supply. There is effectively 3 power supply levels with the JL amps.

 

You've got bigger ***** than I. Can anyone else just see themselves aiming a blow torch at their gas tank to "torch-on" some sound proofing? ...Would Nomex be appropriate? Perhaps the call to your insurance company might go like this:

me: errh, my car caught on fire, sorta also burned down the garage and part of the house .
co: what happened?
me: uh, duh, not exactly sure, there was this freaking flash and explosion
co: lightning?
me: not exactly, it was a blow torch
co: blow torch, so was it arson ?
me: well I sorta had something to do with it, I was melting roofing material onto the gas tank to make my stereo sound better and, uhh, it got a little hot and, like......
co:

Just having some fun with this one, struck me as funny and suprised no one else picked up on it, sat here for 2+ years.

Actually, kidding aside, there is some great info in this thread.

 

Further proof........ a thread is never dead.