Jeep System Sub Box advice

Systems

I would like to have some input from the experts here. I am planning on building a custom box for my Jeep TJ. My hope is the build a box that will house two subs and then mount the amp and CD player to the box so I can disconnect and remove when the top is off or if I want to hose out the interior (advantage of a jeep!)

My questions and concerns I'm hoping you guys can help with are:

1. should the subs be down firing or is forward okay? I'm planning on mounting the box between the rear seat and the tailgate.

2. Should the two subs have separte spaces in the box or can they share the same space? What is the rule for inside volume for a 10" or 12" sub to work properly?

3. Can the amp be mounted inside the box to protect it? Any heat issues here?

4. Any ideas on how to help the CD player not skip while rough offroading? Can it be mounted on some type of rubber grommets to help or would that just cause it to move/jiggle more?

5. Would one of the new MP3 portables work better? Seems like with no moving parts they may not skip. Does anyone make a deck unit with these MP3 "memory chip" units that would have an integrated FM tuner? That may be better than a portable.

Thanks in advance for the help. Sorry for the length, but I know you guys have ALL the answers



3.

sntnsupermen131

1. the subs in my truck are firing forward and they sound great
2. separate chambers, the space in each chamber depends on the subs, they will have it listed with the specs
3. the amp can be mounted inside the box, but make sure it has room to breathe
4. dont use the cd player while off roading...lol...otherwise...some cd players still come with a 10 second anti-skip feature...its very uncommon now...but i think theres still a few out there
5. dont know anything about mp3s
-Cody

Systems

Im a big believer in firing subs down when they will be in the same compartment as you (i.e. hatchback, pickup etc). I built a box to fit in the cargo hole under my rear seats in my 02 Ram and built it to fire down.

Firing subs down will give you a lot more db for a given wattage. The wave builds off the floor and basically rebounds back harder and louder. This is kind of how bandpass boxes work.

It also filters out some of the higher frequencies and makes the bass sound a little deeper.

Other than sheer volume Ive noticed no real difference in my little 8 firing up or down in terms of SQ. I dont know how many more db Im getting but, at the same volume setting, notes that vibrate my mirror violently when firing down, do almost nothing when firing up. Test it out if you have an opportunity. Ill bet you will be suprised.

MTXMAN

MacLeod...

Probably one of the reasons that it vibrates your mirror more when it's downfiring is the fact that the sound waves are being directed straight at the frame of your car, thereby transmitting the vibration directly to the mirror w/o traveling through all the free air...

PoweredByDodge

i think downfiring is best in your situation - again, having an X cab pickup i concur with Mcleod.

as far as the amp, i would mount it outsidet he box, and i'd mount the cd player on top with one of those "under dash kits" -- its 15 bucks, and its a piece of plastic that screws to the box (or under a dash or whatever) and it houses the cd player giving it a nice protective covering while lookin good and makin your install easy as hell...

you can rhino liner the box as well... might help.

Systems

I wasnt basing my comparison of downfiring vs forward firing solely on mirror vibration, I was just using that as an example. The sub firing down was way louder than firing forward with a definite, bigger punch felt in my gut on kick drum notes.

I also didnt mean to imply that downfiring is the best possible way, just that is yields more output. I am on a budget and got a smoking deal on my Alpine 2 channel at Circuit City ($100) so I felt I couldnt pass that up. Considering that this thing only puts out 140 rms mono, I knew I would need a little more umph so I went with firing down. If I were just pooping cash, I would love to have the $500 JL Audio Stealthbox. It is a 10" W3 and it fires up but with the proper amount of wattage (250ish) Im sure it wouldnt matter which way the thing was pointed!

PoweredByDodge

the stealth box that replaecs the middle seat and fires up? -- u dont want that... and i thought that fired down anyway?

1 - upward firing in a truck without precisionplacement is suicide.

2- a w3 is suicide

3- in large air spaces downfiring just rules -- bass is heard best as a reflection off something else -- and when its got to travel 1000 miles before the wave hits something (from box to wall / dash / windows / whatever) it becomes seemingly weaker.

spl probably wont change, but listener's perception of clarity and 'loudness' will proably change for the better when downfiring. it has for me.

Systems

The Steathbox Im talking about goes under the passenger rear seat. It sits in the hole and fires up. It has a 10W3 with dual 2 ohm voice coil wired in series for a 4 ohm mono load. Ive heard these things before and they sound pretty sweet to me. Does it sound $500 good? No way. JL makes some great stuff but they sure are proud of em and the price tag reflects it.

PoweredByDodge

actually when u buy a stealth box - ure payin for the box more than the sub - and even though i despise JL, i'd buy a stealth box -- they're fiberglass... and they FIT well. if i were to buy one i'd buy it online for cheap or buy a used one w/ a broken sub -- and whether the sub was good or bad, rip the sub out andput in a momo or a type R or something i was happy with.