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Discussion Starter · #1 · (Edited)
Hi! First post in a while, been reading through off and on for a time.

I'm trying to create a decent audio setup in the worst environment possible: a 99 Jeep Wrangler TJ. Lots of bare surfaces, no carpet, it was built for an off-road vehicle before I acquired it. I'm in the process of making the interior comfortable again (new carpet, new trim, etc.), and as I'm working on that I'm also working on the audio system.

What I have:
4-channel 400w RMS amp
Monoblock 500w RMS sub amp
Two 4" rounds in adaptor plates (existing front holes are 4x6)
Two 5.25" round component speakers run as standalone speakers in the speaker bar
Two 1" dome tweeters on the A-pillars
One 10" sub in a shallow box rear-facing towards the tailgate.

The 4" rounds are better quality with larger magnets/motors than what I could get in 4x6s. The 5.25" component woofers were chosen because the sound bar is RIGHT NEXT TO MY HEAD and any tweeters present made any sort of soundstaging near impossible. They're closer than the front speakers, and unless I had the fade so far forward that I couldn't hear the back it sounded like the music was playing behind me the whole time.

This sounds okay as is. The bass isn't great, especially on the interstate, but I have some sound dampener that I'm about to line the entire vehicle with, then getting some carpet to put on top of that, and I have hopes that this will improve bass response and reduce road noise a bit. I'll eventually get a dual 10" downward firing custom box for the back, run my subs at 2 ohms and pull about 740 RMS from the monoblock. The midrange is nearly nonexistent, even with the EQ dropped in the highs and lows. I'm piece by piece putting this together.

The tweeters in the A-pillars completely dominate my audio and sound very bright/harsh. I want to lower their output a bit. The passive crossovers that came with the components are unused at the moment.

1. Could I run the crossovers to the tweeters alone and use the -3 dB switch to drop their output? Would that change the impedance of the front channels too much and fry my amp?
2. Could I run the tweeters directly to the front channels of the head unit itself instead of the amp to lower the output but still retain fade/timing control?
3. Are there any ways to improve my midrange?
4. Outside of what I mentioned are there any ways to either improve the output or improve the acoustics of my Wrangler?

The master installer I know said 1 and 2 would work. He also mentioned putting potentiometers on the tweeters' speaker wires, which is an interesting thought, because then I could adjust the output at will.

Thank you all for any input!
 

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I know my input likely isn’t what you’re looking for but in my TJ and a buddies we always ran rear seat removed with a hard top and they absolutely pounded. My TJ was very loud inside even without any deadening but for a SQ setup it could have been better.

Do you have a hardtop? I don’t think a soft top would work well at all. Also one other thing to note is you can hear a TJ with a decent system from a long ways off due to little deadening.

If you don’t use your rear seat often I’d remove it and build a nice size box preferably ported if you want more output. A single 15 or (2) 10s or (2)12s would be perfect. I actually ground my seat brackets off to fit a prefab I had in the early days but don’t believe it’s that hard to take in and out. You get 33-34” of width if memory serves and 35” if you removed the brackets like I did which wouldn’t make any sense for you.

If you used your rear seat on rare occasions you could put a couple handles on your box and make your connections quickly detachable for quick seat installation. If you can’t remove your rear seat I’d get (2) 12s sealed behind the seat that liked small boxes. You may be able to do a single ported sub back there too but it’s been so long since I looked at the specs.
 

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If you don’t use your rear seat and can swing it money wise and want some good bass a single 15” SI SQL would be great on a 1000-1200rms amp either sealed or for more output ported. At least from my brief reading on here.

The sub and amp would run you about 5-600 but you may be able to get a couple hundred out of your current setup locally depending on the sub. Stock electrical should be fine to 1200rms maybe a bit more with a big AGM up front.
 

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Discussion Starter · #4 ·
Wolv19D,

No hard top, though that's on the "eventual list." At the moment it's a soft top. The bass is meh, but I'm going to try out an older 12" that I have in storage, see if it's an improvement over the 10". That plus some deadener I think will give him a little something to work with.

I might try a larger box with the seat folded down. I ran without a seat for years, but it was always annoying to have a few people need a ride and always having to take someone else's car. Having something I can quickly disconnect may help with the bass issue, at least.

If I drop the impedance down to 2 ohm I can get about 780 RMS out of this amp. Down to 1 ohm I can get 1000 RMS and still be stable.

Now to figure out the harsh, overpowering tweeters.
 

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Discussion Starter · #5 · (Edited)
I really want one of those downward firing 2 10" boxes, but they're pricey, something around $450 minimum, up to $600. But they'll fit the back with the seat unfolded, so I wouldn't lose anything and anyone peeking in to my Jeep wouldn't see a huge box in the back.

The SQ setup is brutal at the moment. I need that carpet bad. Fingers crossed on the deadener helping a bit.
 

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If I was going behind the rear seat (2) 10s sealed or (1) 10 or 12 ported would be what I’d do. If you are going sealed I wouldn’t worry about paying high prices for the right box as long as it’s made out of quality materials like 3/4” MDF it’ll likely be fine. The dimensions of the $100 sub box and $600 box will be identical for the most part since they have to fit in the same tiny space. Looking it up you have about 1.5-1.7 cubes max. If you ran (1) sub ported you’d loose a bit of that to the port but it may be louder then (2) sealed and cheaper to only get one sub.
I was in the same dilemma years ago and ordered a couple FI Q 12s to run sealed behind the seat but thankfully ended up making a big ported box for them. I imagine with the back seat and tailgate sandwiching there box together a lot of air won’t be allowed to escape and loudness will suffer. In a similar way as a trunk car with the back seats up instead of folded. But if your not looking for something that really hits hard and just want some decent bass I imagine (2) 10s sealed on 700-1000rms would work well. It may be louder then you think.
A crazy idea if your into fabricating stuff yourself is to design a box that also can be used as a seat if it needs to. Or find a single seat to bolt in the rear so only half of the bench is available for one person to set there and the other half is taken up by a box. So 17” wide for the seat and 17-18” wide for the box. You could run a ported 12” like that very well and incorporate storage on top of the box for cup holders and things for the rear passenger but that’s a bit involved.

When I ground my rear seat brackets off I removed the possibility of installing my rear seat again but I found even without the brackets the rear seat stays in place very well and the bench can be pushed more to the rear giving you a lot more leg room for the rear passengers. It’s probably not safe in a wreck since it’s not bolted down though but I imagine there’s a way you could rig up a bracket with a couple quick release bolts.
I fear no matter what you do if you have a soft top it’ll likely be lacking and the road noise will of course be much louder. I loved having a hard top and if you have a person to help you can install and remove a hard top in a minute or two if you don’t use standard bolts in all the holes at the rear. Use some sort of quick clamps or bolts that unscrew quickly that just get hand tight. I usually only put like 2 bolts in the hole thing and clamped it up front of course and never had any issues. I believe a YJ top will fit and can often be had for half the price of a TJ one. At least that’s how it was years ago I believe YJ tops were $500ish and TJ tops about $1000 on the low end but it’s been 10 years and the prices may have come down on the TJ tops with less of them on the road then there used to be.
 

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Dang phone messed up my paragraphs ... sorry about the wall of text.

And I know I’m only talking about a small part of what you asked but I’m just not knowledgeable on the other matters so hate to comment.
 

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Discussion Starter · #8 ·
No worries at all, I appreciate the input. The half seat idea is intriguing as hell.

I swapped my 10" with an old MTX 12" in a sealed box and it's a very noticeable difference. I'm going to see if I can get another small sealed box for the other 12" MTX I have and run them at 700 - 1000 RMS. I think I'll be in good shape 😁

Today I came across some cheap sound deadener. I didn't have time to install it, but I laid it out on all of the surfaces just as a test and holy crap it made such a difference. A lot less road noise and the sub hits harder. I've read that the stuff works a lot better when it's actually rolled down, so I'm excited. I'm going to prep the interior tomorrow and try to get it all put in properly. In the next few months I'm going to get carpet (the previous owner tore it all out) which on top of the deadener I think will make a big difference.

I was just reading about sound mats for soft tops and I wonder if I can make something myself. Every little bit helps, and I can do it if it's cheap enough.
 

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I don’t know what could be used for soft tops to deaden the sound but for my hard top I considered getting 1-2” thick sheet insulation and Gluing or double side Velcro it up so it could be removed. But it was so loud without any padding I never got around to it.

Any carpet should work If you want to cut it to fit yourself. You’d likely save some money that way too but it may not be as pretty.

for the half seat idea finding a old seat that was low back would be key or perhaps find a scrap TJ seat and literally cut it in half. Sew the open part shut and put a seat cover over it and one side of the bracket will already be installed so just figure out a way to get a bolt in the other side of the bottom. It may require a metal tab to be welded on the bottom with a bolt hole.

I forget what the factory brackets look like so maybe just one side would be good enough to hold it down. And if you put a L bracket on your sub box and bolted it to the Jeep itself you could figure out a way to bolt the seat to the sub box perhaps and it would keep it sturdy. I think a half seat makes a lot of sense and would be badass.
 

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A sub box 17-18” wide would be enough room for a single 15” if you wanted maximum output. Just put a slot port on the bottom of the box instead of side and make it about 20” tall. But a high quality 12” ported would likely put those MTX sealed to shame but I could be wrong. You would have 5-6 cubes easy on that side and could even do 2 subs up and port back if you wanted but a hard top would likely be needed for decent output?

I never heard a TJ with soft top and subs but I know without a top on there is very very little bass. They pound hard with a hard top. Loudest vehicle I’ve had to date I believe. Must be something about the way the air flows in them.
 

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Discussion Starter · #11 ·
I'll have to look at the brackets for the rear seat and think up some options. There are a few used, beat-to-hell back seats that people sell off, either because the Jeep gets scrapped or they decide to toss them when they make the Jeep an off-road toy (that's what the previous owner of mine did).

As for the way it is now I'd love to get someone to make a ported box to fit that MTX (or another sub when I can afford it), though maybe I should save up and do a 15" if I can get someone to make a box with enough depth to accommodate one. Even with a soft-top the 12" slams, and I never take the top off, so for now it works. Just when I get up to speed on the expressway/interstate I notice a heavy drop in bass. That's why I'm doing the sound deadening next week, knock down some of that road noise. I have the mats laid out on the floorboards, not pressed down, and the difference is already amazing. I've read up on a few Wrangler sound deadening threads and the results seem to be solid. I want to get a layer of closed-cell foam to put on top of the butyl/metal deadener to get a stronger effect, then cover it in carpet. If I can find some cheap carpeting (no luck with Google yet, at least for automotive carpet) I'll try my hand at cutting it myself. At the moment I care less about how it looks and more about making it comfortable.

They make headliners for Bestop soft-tops, but unfortunately I don't have that brand, so I think I'll need to make something myself. From what I've read they work pretty well. We're still dealing with a canvas top, so there's only so much you can do, but any little bit helps.

Maybe with the hard top it works so well because the space is so small and the subs aren't separated from the listener by a sealed trunk? Just spitballing.

As for the tweeters I'm going to run my passive crossovers to a resistor network that someone on another site recommended. It'll allow me to drop the output in 3, 6, or 9 dB. I think that solves that problem.

Now I have the pleasure of installing deadener, removing rust, running the crossovers, mounting the amp down, and Tesa taping all of the new wiring I've run. I'm going to try improving the quality of this prefab box by taking wood glue to the seams, letting it dry, then applying latex caulk to really seal it up. It's going to be a fun week 😁.
 

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If you can get by for now with 1" less of headroom I believe the foam insulation sheets I mentioned earlier would work well but haven't tried it myself. It would be a cheap thing to try anyways. I believe 1" is only about $20 a sheet for 4 foot by 8 foot and you could cut it to fit. They make much thicker then 1" as well but I can't say how well it would deaden the sound. But it's super lightweight and would be easy to make fit.

If you do install sheet insulation what I would do is get a roll of double sided velcro. I believe 3M makes some and could probably be had on Ebay for $15-20 for a big roll Clean your soft top well where the sticky glue will adhere (alcohol should work well) then apply the velcro in certain areas then stick up the insulation and press firmly so it will get a good hold on the velcro that's already stuck to the soft top. If this doesn't work or doesn't look right to you simply remove the insulation sheet and you'd only be stuck with some velcro on your soft top. It would be removable just by pulling it hard to undo the velcro. Paint the visible side of the insulation to match your interior before or if you get fancy you could even get some cheap thin fabric from walmart and apply spray adhesive to the insulation and apply the fabric like a headliner. Before going through all that trouble I would test the insulation first to make sure it helps. It would likely only take a half hour to complete most of this.

As for carpet check out Ebay, I bet they have carpet already cut to fit the TJ. And for even cheaper you can probably buy a roll of carpet and cut it yourself to fit. And looking into the rear seat a bit I found in the past companies made split seats you could install.

Check out this page - Jeepin.com » TwinSeats’ split folding rear TJ seats

Forum topic - Split Rear Seat?

I didn't read all of the replies on there and I believe you could find more topics on the matter by typing in "TJ Split rear seat". I don't think it would be very hard if you had someone to fabricate a bracket to the cut in half rear seat.
 

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On the speaker box, you may be able to build one yourself? Do you have any experience with that type of thing?

If you are hands on at all it's easy enough to learn and only cost you a sheet of MDF at $35. On the cheap a circular saw, cordless drill, and jigsaw should be all you need tool wise. Add some fine threaded screws, wood glue, and accurate tape measure to the list. You can have a box designer build you a design or do one yourself with an online program.

The last one I did I designed myself really quick and it turned out very well. Knowing what size box your sub likes and what tuning is best are the most important things to know. You also generally want 12-16 square inches of port area per cubic foot of box net. Subs that move a lot more air with higher Xmax generally need the higher end of that. Then you can just type in the dimensions you have to work with and play with the numbers a bit to turn out a design that has equal dimensions for easy cutting. Or pay a box designer $30 or so to design a box for you and build it. The box designer will take everything into account and build a great design. You may not notice much if any of a difference having a professional design you a box if you do all of the specs right to start with on your design but for a higher end setup it's worth the piece of mind and knowing you got everything right. On a cheaper setup it probably isn't worth it unless you want peace of mind.

If you have the money to spend upgrading your system would be great. Everyone seems to love those 15" SI SQL subs for around $350 that are rated for 1000W but seem to like a lot more. There are a few other good options in the $300-350 range. And a couple that aren't bad in the $200-300 range but not many good quality ones for under $200 I can think of. But I am just getting back into it myself and have a lot more to learn so there may be a sub out there that fits. I'd splurge and go for a good sub to start with at $300-350 and run what you have now power wise and that SQL should sound good on your power and be even better on 1200-1500 watts if you ever upgrade amps.

Without a rear seat you have plenty of room for a 15". Or (2) 12"s. But the 12's will cost more if you get (2) good quality subs. So on a budget a single 15 of high quality is probably better then (2) cheaper 12's in my opinion. And you can probably fit a single 15" in a 17.5" wide box to fit your TJ for a half rear seat setup. The port would have to run across the bottom though and the box would have to be about 20" in height or a little more but it should be doable. A sealed box would be no problem at all. A single 12" ported would fit no problem but I'd likely do a 15" as well if I knew I could fit it just to have the extra output.
 

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Discussion Starter · #14 ·
If you can get by for now with 1" less of headroom I believe the foam insulation sheets I mentioned earlier would work well but haven't tried it myself. It would be a cheap thing to try anyways. I believe 1" is only about $20 a sheet for 4 foot by 8 foot and you could cut it to fit. They make much thicker then 1" as well but I can't say how well it would deaden the sound. But it's super lightweight and would be easy to make fit.

If you do install sheet insulation what I would do is get a roll of double sided velcro. I believe 3M makes some and could probably be had on Ebay for $15-20 for a big roll Clean your soft top well where the sticky glue will adhere (alcohol should work well) then apply the velcro in certain areas then stick up the insulation and press firmly so it will get a good hold on the velcro that's already stuck to the soft top. If this doesn't work or doesn't look right to you simply remove the insulation sheet and you'd only be stuck with some velcro on your soft top. It would be removable just by pulling it hard to undo the velcro. Paint the visible side of the insulation to match your interior before or if you get fancy you could even get some cheap thin fabric from walmart and apply spray adhesive to the insulation and apply the fabric like a headliner. Before going through all that trouble I would test the insulation first to make sure it helps. It would likely only take a half hour to complete most of this.

As for carpet check out Ebay, I bet they have carpet already cut to fit the TJ. And for even cheaper you can probably buy a roll of carpet and cut it yourself to fit. And looking into the rear seat a bit I found in the past companies made split seats you could install.

Check out this page - Jeepin.com » TwinSeats’ split folding rear TJ seats

Forum topic - Split Rear Seat?

I didn't read all of the replies on there and I believe you could find more topics on the matter by typing in "TJ Split rear seat". I don't think it would be very hard if you had someone to fabricate a bracket to the cut in half rear seat.

Oh those look wild! Thanks for digging those up for me, I'll continue to look into that. It would be a wild thing to try, and, man, that would give options when I have a few people to drive around versus no backseat.

As for the foam insulation, I'll take a look at the store tomorrow. That's a killer idea. From everything I've read about headliners it does make a difference, and I really don't mind losing a little room up top if it makes it all more comfortable. I'll have to section is out to accommodate the speaker bar, but it seems worth it.

I'm really not experienced in building sub boxes, or anything involving woodworking, but I have a lot of experience turning wrenches on my Jeep. If it's not difficult to get into then I would rather do that than pay someone $400 - $600 to build me a box. I'd love to find a way to put something reasonable into the tiny trunk I have with the bench seat installed, as I don't think I could do the split seat for a while, and there would be times where I'll need to sit four people in the Jeep.

I did find a ported tube-shaped enclosure that would fit a 12" that might fit in the back. At least it would be better than a sealed box, but it only has about 1.37 cu ft, and a lot of the subs I like need 1.75 to 1.85 cu ft. I'm not sure how much this would damage them if I tried to run them in an enclosure this small, but from what I've read it's a no go.
 
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