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Guest Message by DevFuse

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My custom subwoofer enclosure ('85 GL Wagon) (9/28 UPDATE!!)

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17 replies to this topic

#1 syphon


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Posted 07 September 2003 - 04:09 PM

So as I'm sure many of you are aware, Subarus are a bit easy to break in to. My friend Tex has had both his Subarus broken into and a LOT of moneys worth of stereo equipment stolen. The guy I bought this wagon from had his subwoofers stolen from it about a week before I bought it.

I wanted to add an amp and some subs to my Subaru. Nothing too boomy, but something to round out the sound. I don't have a cargo cover, however, and I was worried about potential theft.

I have to thank Austin for the idea, because he mentioned he had a pair of 8"s he would be willing to sell me. They came in boxes, but I started wondering if there was something else I could do with them.

The following is the product of a few days work by Tex and myself.

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Basically I just cleared out the little storage area underneath the carpet. I then went to Pull A Part and grabbed a new gate from another wagon.

Tex and I then drilled holes to mount the 8" subs to the bottom of the gate. We had to use a LOT of bolts to space the subs far enough from the gate so that they wouldnt slap the gate when firing, then we used some rubber washers to cut down on the uber-exessive rattle.

After that, We took some foam tape (insulation tape actually) and lined the edges of the gate to cut down on the rattle. Then we cut a piece of wood down to size to seperate the chambers for the amp and the subs.

After lining the sub enclosure in dynamat (which is expensive!) We were done.

I plan on cutting some holes in the gate above the subs for a bit more volume. What I want to do... is drill a BUNCH of little holes, so that the top of the gate has the appearance of speaker grills, and I wouldnt have to worry about damaging the speakers when putting stuff in the car.

What do you guys think? Any comments? Suggestions?

#2 Subarutex


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Posted 07 September 2003 - 04:13 PM

I think its rad. We do need to drill some holes so you can get some more volume. I kinda wished i had done something like this back in the day to my wagon. BUt big huge 12's sound so much better in a huge box. To bad its hard to hide.

#3 Flowmastered87GL


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Posted 07 September 2003 - 04:19 PM

Thats a pretty good idea there... :clap:

I think you should go the small holes route also and make sure not to drill through the carpet, total stealth mode on the stereo :D

You DO plan to drill a bunch of holes to let the amp get cool air too right???

#4 Ratty2Austin


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Posted 07 September 2003 - 04:20 PM

nice to know that my 8's are still getting good use seince their original purchace for my high school 83 wagon, back in '98 & '99

hope it sounds good too! (you are going to stop by and let me hear it right? :D

#5 Bratwerst


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Posted 07 September 2003 - 04:24 PM

Good show! I love things like this. I too have had several cars broken into and it sucks that things like this need to be done because of some &%@... yea - but seems it brought better ideas about - and you executed them well (I've been talking with a friend about something similar with his wagon - different execution though) So hows it sound? We already know it looks... um... non existant :D

- Erik Hosa - Tacoma, WA -

#6 TheSubaruJunkie



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Posted 07 September 2003 - 04:32 PM

That is a DAMN GOOD idea. Wish my EA81 had a storage bin like that.


#7 syphon


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Posted 07 September 2003 - 04:33 PM

As far as sound goes, I'm pretty disapointed. They sound WAY better in the box. I hope drilling some holes and tightening things down will help (I bought a latch to help tighten the tailgate). There's just not enough to fill out the bass.

I also suspect one of the speakers is messed up, since there's something INSIDE the speaker rattling. We have to investigate it more, but I hope we didnt damage the speakers during the install.

#8 GeneralDisorder


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Posted 07 September 2003 - 05:16 PM

Just remember to follow the golden rule of thump - "Never play where you park". My buddy found this out the hard way with his 4 runner. He had 2 12" Audiobahn subs in the back, with 1500 watts driving them - all gone.


#9 PoorManzImpreza


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Posted 07 September 2003 - 05:53 PM

ok guys my 2 cents;

the space between the subs mounting flange and the cover must be illiminated and holes must be drilled in said cover to allow the front pressure wave from the subs to vibrate the air in the car, but not the air in the box...at no point must the back wave and front wave meet out of phase with each other which is what is happening in your setup with that space.. also find a way 2 fasten the storage cover to the car or else the pressure wave from the back of the speaker will push it open assuming the above has been done..the purpose of the box is to isolate the back wave from the front wave as they are 180 degrees out of phase with each other and cancel out any sound below a frequency determined by the diameter of the cone..

it is a good idea and will be nice once you figure out a way to do the above and also if your amp can handle it run the subs in parallel and not in series as you have them..also if you must run them in series make sure you go amp+ to +of right -of right to +of left - of left to - amp. left and right can be interchanged in the above so it can be amp+ to +left -left to +right -right to - amp....

umm ok nuff said

#10 syphon


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Posted 07 September 2003 - 10:58 PM

You have wonderful suggestions there.

So today we modified it a bit. We were driving around, and ended up at some car stereo places. We saw some MTX 8"s that were a steal, so I got them. They sound a bit better than the other ones, so now I have MTX Thunder 4500's in there.

As far as future plans, this is what I want to do.

The suggestion to remove the space between the subs and gate has serious merit. I'm going to remove a couple of the bolts (whatever is safe to keep the sub from slapping the gate) and then cram some foam tape in there to seal it off (unless anyone can think of a better solution).

I'm also gonna put some foam tape on top of that wooden board, and maybe below it too. Anything in an effort to seal that compartment off.

You'd be surprised at how the weight of the subs seals the gate to the compartment. I think that I want to ensure this is sealed properly, so I'll put some latches on the gate. Think of the type of sliding latch you'd see on an outhouse or a bathroom stall in a restroom, I'll put on of those on each side to keep the lid sealed down.

Also we're going to drill holes in the gate... Don't know how much of a difference that will make.

As far as the amp goes, I have to run them in series. The speakers are 4ohm speakers, and the amp is only 4ohm stable. With them in parallel, it's a 2ohm load and the amp tends to crap out on that. This is a definate poor man's stereo, so getting a better amp is not going to happen.

#11 baccaruda



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Posted 08 September 2003 - 12:31 AM

that's really nice. I don't want to sacrifice the smuggler's hatch though so eventually I'd like to make custom side... uh, thingies, taking up the rest of the space next to the wheel wells. It'll cover up the side compartments but I plan to incorporate something else, maybe drawers. I also saved the carpet from my last gray 86 T-wagon, so I can make it look factory carpeted.

A couple suggestions: Get or make a cargo cover. It would be easy to screw in 4 attachment points where the stock spring loaded CC attaches, and you could probably get some matching vinyl from an upholstery shop if you can't snag a stock CC.

Also, close the sub box with hood pins! :burnout:

#12 MilesFox


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Posted 08 September 2003 - 01:45 PM

cool! me likey likey! its like the direct opposite of the "Roof of Boom" the floor of boom?

anyway, i like the idea of having speakers and such without using up your wagons cargo versatility. mine was on the roof, an 83, doesnt have the smugglers box....

yeah, drill holes for sound, but so nothing will poke thru and dameage the spaeker.

pack some fiberglass insulation in the box around the spaekers, it will give more "mass" to vibrat and give deeper bass. that one is mentioned in radio shack's "building speaker systems" book

that way the bass is shaking things up, will help make up for sound coming directly out of little holes.

drill the holes out rather large, at leadst 1/2 inch to 3/4, close together, it will still act like a flat floor for strenght

use one of those flat spade type drill bits for cheap, as any large bit will be expensive an only fit in a drill press

#13 syphon


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Posted 08 September 2003 - 02:38 PM

The fiberglass insulation sounds like a good idea, I never even considered it.

I'll work on it some more tonight when I get home from work, like sealing up the sides around that wood block and stuff.

#14 MilesFox


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Posted 08 September 2003 - 06:02 PM

if you were to seal up the speakers against the lid, it would act like a regular speaker box. the piece of wood being sealed off wouldnt matter as long as the whole lid is sealed off. there is a golden ratio when it comes to speaker enclosure size, also mentioned in the radio shack book.

you might as well go get the radio shack book, it goes a lot into the principles of speaker dynamics, and knowing a little will hwlp you to get your setup to sound better than the typical "big amp and big speakers but doesnt sound good"

having a good sounding stereo is more about how your setup is rather than how big your components are.

the book also tells about series and parallel circuits, ohm ratings, and bridging the amp.

its good knowledge worth knowing when you go to set up a stereo system!

let me know it it sopunds any better

maybe adding a tube bass port somewhere between the amp and speakers (you could probably remove the wood if you have enough dynamat for the whole enclosure) you will get better sound by allowing the box to "breathe"

the more air you can move around the better it will sound

#15 syphon


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Posted 28 September 2003 - 06:43 PM

So I just finished up some more work on this.

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Here you can see I drilled some holes for more volume.

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And here you see i've lined the outer ednge of the speaker in foam, to seal it off to the gate.

I'll be getting some fiberglass insulation soon (where can I buy something like that?).

#16 TomRhere


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Posted 28 September 2003 - 08:45 PM

I like this set-up. Stealth jams... Not much into the thump-thump sound myself, but I do like a good sounding system, be it a home system or in-car system. 'Specially if it's jamming some ZZ Top... As for the fiberglass insulation... Got any construction sites around you? You could probally get some small pieces for the trouble of asking... On sealing up the enclosure... As mentioned previously, you need to "vent" the inside of the box to the outside of the box. Take a look at any good speaker enclosure, you'll find the venting method. Be it holes in the back panel, or a vent tube routed to the front behind the cover/grille. With out the "vent", your speaker is fighting itself to move. IE; when it moves forward, it's creating a vacuum of sorts behind it. When it moves towards the magnet, it's trying to compress the air behind it. No worky to good with out vent. Distorted sounds. Also, proper polarity of speaker wiring is key to good sound too. Reversed polarity will give distortion to some of the frequencies of the sound waves. Be them highs or lows. Just some info picked up over the years there is all......

#17 MilesFox


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Posted 29 September 2003 - 10:24 AM

some spekers are designed to be spring suspended, or air suspended.

A spring suspended speaker will have a rigid accordian shape rim around the cone to the frame. these speakers are for an open application like a car door or dashboard.

the air suspended variety are designed to be in an enclosure, using the compression of air to bounce the cone on pressure wave. these are for enclosures such as bandpass boxes and such

you could get away with ow it is for the spewakers to work enough to hear, but making a port (about 2 in diameter) will get the air to move around.

all of this is in the radio shack book previously mentioned

#18 calebz


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Posted 29 September 2003 - 10:31 AM

... As mentioned previously, you need to "vent" the inside of the box to the outside of the box. Take a look at any good speaker enclosure, you'll find the venting method. Be it holes in the back panel, or a vent tube routed to the front behind the cover/grille. With out the "vent", your speaker is fighting itself to move.

This really depends on the sound your after..

I have been running sealed boxes for a long time.. vented/ported/bandpass boxes get better boom, but reach distortion levels at lower wattage. sealed enclosures get better thump.

as far as the speaker "fighting against itself".. that isn't entireley true either. that fighting is what allows for higher wattage in sealed boxes. the airpressure behind the speaker stops the speaker from overtravelling its voice coil.. which is what causes fried subs.

vented or sealed is a preference in sound, not necessarily o function of the speaker.. check the crutchfield compatibility chart somethime.. some speakers are designed for vented.. some for sealed.. some work in both.. then on top of that, there are, as miles stated, free air subs.

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