TomP

This summer, all my old stereo stuff is coming out of the basement, and going back in the car. (I miss the bass!) Anyway, I'm thinking of new ways to do the system; it's not my priority to spend millions in cash to get the system back!

The old "basement-banished" system consists of two 12" Pioneer free-air subs on a plate that went over the well. The sub amp is an ancient Sherwood BP240 in 2-channel mode. Interior amp is an old Blaupunkt 4x20. The amps sat in the bottom of the hatch well, on a board.

I'd like to do a sub box, and make it out of fiberglass. A friend of a friend has two Pioneer premier 12" subs that he's not using anymore, and will let go for damn near free. Same guy has a Pioneer two channel amp (not sure of any specs here) that he doesn't want. I might ditch the old Sherwood for the Pioneer, and use only one 12" sub.

But what the heck are my mounting options?? The 'net is slow, and not all of the pictures of sound systems on thirdgen.org loaded, but it seems that most people do one of two things. Most common is to build a box for the hatch well, and put the amps above the gas tank. Second common is to use a plate for the hatch well, and put the amps above the gas tank. I see a trend!

I hate the thought of putting the amps above the tank; it's a pretty high-visible area, even with rear window tint. Plus, it'd make beach trips a little more difficult; don't want the boogie board catching fire because it was sitting on a hot amp!

I thought of maybe mounting one sub in the bottom of the hatch well. I'd make a custom fiberglass box for it, and give it whatever airspace that Pioneer recommended for the sub. Then I'd put the amps on a board above the sub. I have the feeling though that the sub would vibrate the hell out of the amps, and work the solder right out of the boards! Too bad; I envisioned using slightly-worn-down hood prop struts, and using a junkyard hood latch, so I could raise the amp board, and then click it back down.

Then I thought of copying what I have now; put the subs in the bottom of the hatch well. Maybe I could make a fiberglass box "hang" above the subs... but what do I do about airflow? So I thought I could somehow rig ducting between the wheel wells and the side panels, so as I drive, cool air gets shoved into the hatch well- but then what do I do about rain? Turn the subs off? Do some kind of complicated waterproof duct?

I'd really rather not hide a little 6" sub in the spare tire well... and I don't want to drive around without a spare tire, either. And like I said, I want to use fiberglass; MDF is just too damn heavy! The air shocks are getting ditched this summer (had 'em since '94!), and lowering springs are going on. I'd rather not drag my bumper around town, or have to take the system out to get a decent 1/4 mile time at the track. (YES I know it's just a v6- which makes the weight thing even more important.)

Any suggestions? Any websites of 3rd gen f-body systems that "break" the ordinary pattern? It's times like this I think the sedan guys are lucky... imagine having a whole trunk to play with?

si_camaro

I don't know if this will help you, I'm just putting it here to get my post count up (only joking Brad & Dirk )

I'm thinking of building a box for the rear well, but instead of having it sit in the well right down on the floor, I'm considering having it sit on the 2 "step" like parts either side of the well, making it a little shorter to sit flush with the gas tank, but also wider to stretch the whole width of the well area. Make sense? That would leave the bottom of the well empty, free of the harsh vibrations (more free than inside the box anyways) to sit the amp(s).

jawzforlife1

I made a box that sat on top of the rear seats (with the back rest out) and a notch in the center to fit the hump. Looked nice. Migh want to try that.

FyreLance

REZN8R makes stealth boxes that can hold a 12" in the spare tire well.

TomP

SiCamaro, yep, that sounds like the way to go- but how will your amps stay cool? That's what keeps me from doing it... don't want to start a fire or anything. Hey... hm... what about making some kind of cooling ports in that box that connected the "under box" airspace to the "car" airspace? Hm. Shoot, that'd still need one hell of a fan, though. The side plastic on the driver's side would be a great way to get cool air from the wheelwell...

jawz, thanks for the idea, but I'm not a fan of yanking the rear seatback out. Plus, then the system becomes ultra-visible! And where am I supposed to throw my garbage without a backseat?

Fyre, thanks, I checked the link out. It does seem like a nice little sub box. It's definately an option. Especially since I wonder how a box that little would do "outside" of the plastic area... sitting on that ledge that SiCamaro mentioned.

Are the JL's the only low-airspace sub out there?

Z28ricer

iTrader: (2)

Soon as I sell my Boston Pro 10 im going to test a Image Dynamics IDQ 10 in the stealthbox, i have it and with the huge displacement of the boston inside the box, i think its whats killing my low frequency due to lack of airspace, the idq's call for .25-.50 so we'll see how they do.

Azure

what I had...and no, seeing out the back wasn't a problem at all. This is a LARGE box for one sub, too, a smaller dual box could fit no problem...

CAMp3RO

how big is/are the amps? try putting them in the driver side compartment and/or near the spare tire. as it stands right now, i have a single 12" box in the bottom half of the well with the amp mounted next to the sub. i plan on getting a locking hatch cover. the box is low enough to clear the cover no problem.

nikh23

Could you make a plate that hangs off those two indentions in the well and mount the amp to the plate? I'm not sure if thats what you're talking about. And also check out Zephers setup, he made himself an amp rack that sits on top of the gas tank hump but also has a cover for it. Not sure how its secured down and how the amp gets ventilation but i'm sure you could always throw in a small heatsink in the lid of the amp rack somewhere.

MartyMcFly

It holds a 10" in the cargo area on the opposite side.

cdoyle

Here is how my amps and subs are mounted in my car right now.



If I'm reading what you want to do, mount the amps under your sub box? I don't think this would be a good idea, you would have pretty much no air flow to keep your amps cool. So on a hot summer day, your amps would be shutting off all the time. Plus to get the right amount of air space for your subs, your going to need as much as that well as possible for your box.

Plus I know that sometimes these cars tend to leak, and the water ends up at the bottom of that hatch. Which is bad for electronics. Not sure about your car, but just something to think about.

Your choices to where to put the amp are pretty limited on these cars.

If you go here
http://www.oz.net/~cdoyle/audiointro2.html

You can see some of the previous installs in the car, maybe get some ideas from there.

Chris.

redcamaro83

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TomP

Like I said in my original message, that was my current setup, two 12" free-air subs in a plate over the hatch well. But thanks!


Like I said in my original message...

...I had already known about the overheating problem. I'm no newbie to car sound systems!

My car doesn't leak water; commonly, the weather strip between the outside of the hatch window and the hatch's "fill panel" (usually has a spoiler on it) deteriorates, and that's how water gets in the back. I'll attach a picture.

You're right though, the choices are pretty damn limited, and it sucks. "Redesigning" an f-body system is only applicable to putting new components in, there's nothing original possible about the layout of the components.

"Back in the day", in 1994, I had a Pyramid Pro amp hidden behind the plastic of the cargo area on the driver's side. It worked alright, but in order to maximize cooling (of course), the amp was mounted horizontal. The amps I have are too large to be placed like that. They'd have to be mounted vertically, which would suck for cooling.

Thanks for the link! Your one system, with the blue carpet and the RF logo, looked really sweet! Nice job! Damn theives. I had a system stolen too; they got everything except the Sherwood amp, thank goodness. I'd still love to know how they worked the plate with the subs on it out past the hatch window without breaking the window (again, thank goodness they didn't break the hatch window)! Damned punks; if I ever see a set of subs with metallic blue paint around the center cones, I'm kicking someone's *** right then and there.

RedCamaro, nice system, but don't you miss having a spare tire?

TomP

Oh friggin hell; forgot the "leak" picture. Hope this helps some people out there...

You can either buy a new weatherstrip, remove the hatch fill panel, put the new strip in place, and replace the hatch panel- OR, you can razor out a strip of the old weatherstrip, against the window. The old stuff usually "shrinks back" and leaves a gap. After you cut a larger gap, use a tube of Permatex "Black Silicone" (weatherstripping) to fill the void. Lay down a big BLOB of it, and let it dry. When it dries, go back with your razor blade and slice the blob at a slight angle, so the "thickest" part of the silicone is against the window, and the "thinnest" part will be highest, against the top of the fill panel.

Oh and What the Heck is wrong with thirdgen.org- it's so damn slow?? I'm on a fiber line, every other site is fast except this one!

redcamaro83

nope i have road assist on my cell and NNA
Negro Needing Assistance

cdoyle

Ya those darn theives, I'm just glad I had insurance just incase something like that ever happened.

Lucky for me, mine doesn't leak in the hatch area. The problem I have is its either leaking around the T-tops and making its way down to under the rear seats, or leaking up where the hatch mounts are.

I know its not the weatherstriping that goes around the glass, because I have totally sealed that up. So its coming from somewhere else, and it sucks because I can stand out there with a hose all day, and it won't leak, but sure enough first rain, that back seat is full of water.

Thats going to be this summers project, FIXING LEAKS

joezero

There are a few other options. One is to use just one sub, and build a box that goes down into the well but is only say 6" wide. That way you still maintain most of the space, so it doesn't look so crowded back there. Another thing is that if you're having to notch the enclosure to accomidate the hatch pull down, you can go a little farther in with it and have room for the amp. This is a pic of my brother's box to illustrate what I mean.

Hawk92z-TDZ

U can fit 10"s were the 6x9's go, keeps them hidden and knowone would ever know u had subs.

CaysE

Here's what I'm going to (attempt) to do with my setup, which I think may work well for you, as long as you're ok with having the subs in the rear hatch. I have two older Infinity Kappa 10" DVCs in a sealed MDF box, which is flush with the top of the gas tank and sits on the two "steps" by the spare tire and driver-side compartment. The subs don't need much air space, so the box doesn't extend into the lower well. I also want to find a good hiding place for my amp, so my best idea so far is mounting it on the underside of the sub box upside down. This would hide the amp and any trace of wires in the car, and the rear deck mostly covers the subs. With tint or a roll-out hatch cover, noone will ever know they're there, and since the amp isn't on the floor, you don't have to worry about water.

I realized quickly that cooling would be a problem, so there are a couple ways to fix that. If I didn't have the box already built, I would build it with two ports, one each on the left and right of where the amp will be mounted, going from the top of the box to the bottom. Somewhere in the middle of these ports, I would put two computer case fans, one on each side, one pushing air down and the other pulling it up. It would be the exact same idea as having two fans in a computer, and would keep the amp plenty cool.

Since I have the box already built, though, I plan to mount the fans somewhere in the plastic trim that covers the hatch motor. It won't be as effective as having them in the box itself, but will certainly do the job.

The other idea I haven't seen posted yet, is having the sub(s) wherever you want them (hatch, spare tire well, sail panels, etc) and mounting the amp in the backrest of the rear seats. When you fold down the seats, you see the amp; and you can fold it back up and (mostly) hide it, and still have room for envious passengers.

Good luck!

joezero

There's a tech article on it here:
http://www-ec.njit.edu/~ljd8271/amplifiers.htm

88txiroc

That is what I just started working on today. Gonna take some time, but I want my two amps in the rear seat. I will take some pics along the way, but I dont plan on finishing it for a while. Just going to work on it here and there.

cdoyle

One word of caution about mounting the amp upside down. When you do this, your disabling the heat sinks on the amp. So instead of the heat being transferred from the mosfets, to the heatsink and then off of the amp. The heat is being trapped inside.

I'm not sure if the fans are going to be enough to keep it cool, because the heat is trapped inside the amp.

Chris.

joezero

Great minds must think alike, I just started on this too! Except I"m doing a PSone instead of amps. I'm hoping to have it all finished and back in the car by tonite. I'm doing a little different than the tech article though.

CaysE

Heat doesn't necessarily move from bottom to top, it will spread evenly in all directions. Hot AIR will move up through colder air, and the same with liquids, but heat radiation spreads in all directions, so the heatsinks will perform their function, and the fans will do the rest.

If you're really worried about it, put half-inch spacers on the screws to give a little room between the amp and box.

TomP

Problem is, heat rises. And last I've seen, no amp manufacturer puts the heat sink on the bottom of the amp. You'd be cooking those suckers! A better idea would be to mount the amps to the underside, as planned, but use LONG spacers so the heatsink is facing upwards- almost as if the amps were bolted to the bottom of the hatchback well.

Nice install, Hawk! Talk about a tight squeeze! How's the vibration from the sail panels? Get any noise?

Joe, I was thinking along those lines when I designed this sketch. Not sure if it'll fit my amps, though. Plus I'm not sure how the angle of the subwoofer will work with the sub's ability to use the full airspace of the box. The sub would go on top, obviously, and the fiberglass box would extend into the hatch well. The amps would get mounted to either side of the subwoofer. It limits me to one sub, but keeps everything hidden.

Only two problems- if the angle of the subwoofer-mount will hinder the sound of the sub, and, how the hell I'd get to my spare tire if I got a flat.

joezero

Tom, I don't know if you've seen my setup, but it goes from side to side, and I can still get the spare tire panel off. It's a tight squeeze, but it's do-able. It really shouldn't matter what direction the heat sinks face, so long as there is enough air around them, and that the heat can escape. The other thing is that you can use a class D amp, it will generate a lot less heat.

CaysE

Sorry Tom, but contrary to popular belief, heat doesn't rise. The reason heatsinks are on top is because, since most everyone mounts their amps rightside-up, the heat from the sinks will cause the air around it to rise, drawing in cooler air from the sides. You can mount an amp upside down with no problems, as long as there's air circulating through the heatsinks.

People will mix this up all the time. Heat itself doesn't rise. Hot air will rise, hot liquid will rise, and hot solids would rise if they could, but they can't. This is why heatsinks can be mounted upside down. The heat will radiate through the heatsink no matter which way it's facing. The problem arises when the heatsink warms the air around it. If it's upside down and there's no circulation, hot air gets trapped in the fins of the sink. This is why you would need fans.

Trust me, it does work.

SinthetikIroc

iTrader: (1)

he is correct about "heat" itself not rising.

TomP

Hm; interesting stuff. I guess it makes sense if heat is an energy, and metal's just the conductor of it. But I'll still keep my amps heatsink-up!

But, nobody has anything else to say about that sketch? Hm. It's either a sure winner or a sure loser, then!

joezero

Tom, I don't know about everybody else, but your sketch has me a little confused. Are you intending the center section to go into the bottom of the well and the side parts to sit on those little "steps", with an amp on each side and a sub in the middle? Or am I looking at it wrong?

CaysE

The sketch is pretty simple... The sub is mounted in that triangle protrusion, and the amps are on the sides. Your problem would be hatch clearance if you did this, though it's certainly possible.

I'd say a better idea is putting the amp in the middle and subs on the sides.

Hawk92z-TDZ

Not that bad actualy, I havnt noticed anything myself when in his car but then again the four 15's could drown out any flutter they make.

We will be doing a setup there for an other friend along the same line with two 10's and tweets, but with a custom baffle replacing the sail panels, and the speakers will be mounted visable to the baffles. It will take abit of costom work, but it should look good when finished. I'll post some pics when we get it done, we wont be starting it till closer to the end of the summer. I will prolly be going 8's and tweets there in my car with the same visable baffle setup, at least thats what I got curently planed. To busy working on the engine right now to worry about it too much.

P.S. Heres another spot for sub's. He has two 8's in each door.

CaysE

as if the doors weren't heavy enough nice work though!

84 1LE

iTrader: (9)

Ive had this set-up on my 84 for well over 10 yrs.The coustic amps is almost 12yrs old.It runs my 12in cerwins/dual coils on 2ohms ea.It has NEVER had any heating problems,not even a blown fuse.The MTX amp runs the 6x9s/4x6s & two 3in speakers in my kick panels.Only my 6x9s are running on 4ohms.This amp is about 2yrs old.As long as there is room above your amps they will get enough air to cool them down.My amps are mounted to a board covered in matching material.Only gravity keeps the board in place(& weight of amps).My subs are mounted to a board that i made using the original lid as a template.My CD changer is mounted between subs & never skips.I even used the original lock to keep my lid from bouncing up/down while driving.Its also covered in similar material.I will post a pic below of lid(closed).

84 1LE

iTrader: (9)

Here are my subs/lid.This set-up allows me to still put my t-tops back here & strap them down,or anything else that will fit back there.

TomP

Joezero, yep, you got it right. CaysE, I completely forgot about the latch area; looks like the sub would have to be moved forward, so there'd be yet another angle involved. (sigh) Don't think this is gonna work; I've gotta actually open my hatch and do some measurements.

841LE, yep, that's the setup I have now; a hatch plate over the hatch well with two 12's, and the amps on a board beneath. I'm trying to get an actual sealed box out this "new" deal, though.

Do you guys think mounting the subs above the amp will pose a problem for the amps? As in, vibrating them to hell and back? I guess, too, that I'd have to leave some kind of airflow "out" from the front cone of the sub. Hm... wait... could this be done into a bandpass kind of enclosure? Let me try another lame sketch again...

Well, this might wind up looking like total crap if I built it...

But would the subs murder the amp in terms of vibration? I know people screw their amps to their subboxes, but would that be a lesser vibration or greater vibration? With an amp on a sub box, vibration hits the amp through the wood; with my question, the vibration hits the amp through air. Seems like it'd be -less- vibration; I'd imagine the solid surface would transfer more vibes to the amp's circuit board and wire connections, but we all know how theory & practical application differ!

Thanks!

Hawk92z-TDZ

Thats Y the weights kept up at the hinges We were gunna put them at the other end of the door so we would not have to build out the panels so much because of the window motor, but they look better at the front and the sound isnt slamming in the side of the seat plus of course they added weight issue

Nice loud mid bass punch, moves the pant legs pretty good

Just a couple speaker spots to keep your hatch free of sub's.

Good luck with your design Tom, personaly I wouldnt mount the amps right above the subs, circut boards are just to easy to break with mass vibrations. Just my .02$

TomP

Yeah, that's what I'm thinking, too. I am toying with mounting the subs in the first pic you had, by the rear seats... nobody sits back there anyway. The doors are a little too high-visibility for me...

joezero

I don't think that your second design would work for a couple reasons. One, a bandpass box would need more space (technically it's like 2xs the size of a sealed enclosure. I've never built one before, so I'm not positive on the math, but in my experience, you have to have the required airspace on both sides of the sub in a bandpass setup). Two, even if the amps didn't break internally from the virbration, I have a feeling that the screws holding them down would work loose. But it's difficult to say for sure. I almost always mount the amp (s) to the enclosure. I just like the completed feel it gives the setup.

In terms of what you could do, there are a few options. One would be to fiberglass the bottom of the well and up on to the little "steps". Then build an MDF box on top of that. That way you could maximize the airspace and still maintain the convience of MDF on the top/sides. Then there could be a sub on each side, with both amps "stacked" in the middle. I've seen setups with the amps like that before, where they've got the amps at like a 30* angle and one on top of the other. Then you could just recess it a little bit (or a lot ) and then you would have a seperate amp rack and subs, although it would all be one unit.

Another option is to go all fiberglass. I've seen some fourth gens that had like 2 bubbles that each held a sub. (I looked for a pic but couldn't find one. One of the cars in the "f-body havoc" videos on www.f-bodyhideout.com ) There are also stealth enclosures for fourth gens available, I don't know what would be involved in fitting one in a third gen.

One last thing, what about those flat subs that have a mounting depth of like 3"? I suppose that's not an option if you were planning on re-using your old subs, but it's just another thought.

kDB

i've done this with 3 JL 10" W6's, and faced them backwards towards the taillights. the little well kinda act's like a bandpass box. though i set the amp above the gas tank. sounded very nice, but you need to make sure the speakers can handle that small a space.
now i remember why i got that digital camera, now if only i cold find the pc-link cable...

kDB

TomP

Joe, true, I forgot about that bit. (Uh, I mean, I didn't do my drawing to scale! ) It was mainly an idea to give the subs something solid to mount to. Putting a board over the top of the subs and mounting the amps to the board (and the board to the car) probably wouldn't make for much bass. Plus I hear bandpass is a btch to build... I don't really want to spend 2 weeks making a stupid subwoofer box! Okay, decided: Scratch the bandpass idea.



See, what is different about mounting the amps to the enclosure as opposed to mounting them above the sub? Is it just added vibration from moving air? I'd think vibrations would carry through a solid surface with more force then through air... no?

I'm not really planning on reusing the subs; they're free-air's, and probably wouldn't act too well in a sealed box. I'm definately going fiberglass, and I want to use -ALL- fiberglass - no heavy wood. I've done bodywork; fiberglass can't be -that- bad, especially since I really only have to finish the outside.

That 30 degree angle idea sounds good; if the amps fit. But still, mounting the amps above the subs- isn't that the extra vibration that you mentioned? Flat subs, eh? Who makes 'em, anyone remember? I'm not out to spend $1k a sub, either

My MECP buddy gave me an idea.. he told me I could probably mount the 20x4 amp underneath the box, since it won't get as hot as the sub amp... then I'd just have to have the sub amp "up top". But I dunno, that 20x4 has gotten pretty hot on a 95 degree summer day.

If only I could find an efficient way to pipe air underneath the sub box, I wouldn't be having such a hard time with this. Damn!! I gotta sit down with some measurements and some drawings I guess. Do computer fans even move enough air to be worthwhile? Or would i have to pick up a squirrel-cage blower from somewhere? And I guess I'd need two of 'em, one on each side.... damn, what a PITA. Oh for the room of an SUV...

I wonder if I could do that 30-degree-angle-stacked-amps idea with only one sub? A sub on the left, cutting off half the hatchback (and maybe extending into the side compartment), and then the amps on the right?

joezero

Where to start...?
I think that the computer fans would be fine. Refering again to the tech article on putting amps in the back seat, he used a couple of computer fans with out any problems. And his amps were sealed under plexiglass and surrounded by carpet. In regards to the 20x4 amp: I have had the thermal protection kick on for mine after about ~1 minute of max volume playing if I leave the car parked where the sun shines in on the back window. Just because it's rated for less power doesn't mean it won't heat up just like a sub amp.

As far as stacking the amps, it won't take up any more room width wise than a single amp would. So if you could fit an amp and two subs (which many people have done and more), then you should be able to in this instance as well. Maybe what you'd want to do is put the two subs next to each other, and the amps over on the driver's side. That's how my brother's first setup was so that the baskets would go into the bottom of the well. I don't know if I have a pic, I'll have to dig around tonite and see if I can find one. If you can find subs with a low airspace requirement, you could fiberglass the well and keep the height as low as possible. I think it was white ninja that just finished up one like that, and he ended up with a little over 1 cu. ft. if memory serves me. Also Redbird did a rather lengthy thread on his construction of a fiberglass enclosure with a lot of pics.

My friend and I were planning the system for his 4runner and he says "I don't want to lose any space". And I'm thinking "have you seen my car?!? You could fit a small country in the back of yours!" I tell ya, SUV owners

TomP

LOL! Hey thanks for the ideas; I'll do some searches on those names and see what I can find. I just hate the idea of someone being able to look thru my tint and go "hey, look what this guy has!" I'd rather them just see subs. Maybe I could paint "pyramid" or "legacy" on the sub cones?

joezero

Unfortunately I don't think it'd work. In my experience theives are too dumb to know what brands are good.

chevylover5

iTrader: (1)

idk about you guys but the neighborhood i live in isnt the best, being right outside of philly, but doesnt this kind of scream break my window and steal me?


I have two tens in the hatch and I built a rear seat delete to hold the things that I used to keep in my hatch... no pics cause im too lazy to put em up but maybe ill post sum later
-ken

82firebird

Holy 4 year old thread revival.

AmorgetRS

iTrader: (6)

If this isn't living proof that the search DOES work I don't know what is :-D

chevylover5

iTrader: (1)

i aim to please gentlemen...and ladies lol

BlueSmoke

Yep search works fine as long as you use it.


Beyond cutting the plastic, did the guy who put the 10's in the sail panel have to fab up a mounting bracket beyond cutting the 6x9 plates? How much rattle does this setup give off?