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Discussion Starter #1
my idea is to use my spare tire tub as an enclosure, build a frame above it (if needed for airspace) or run a peice of mdf over top or recessed with braces to the sides. I am thinking of covering the sheet metal with oilbased clay to seal and prevent resonating of the metal. I just dont see how a fiberglass box there would help other than being able to take the whole thing out.

I would appreciate anyones thoughts or questions about this as it seems like a much easier and space saving method.
 

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Discussion Starter #2
I also wanted to possibly use the same enclosure to house the subwoofer and a midbass woofer, unless the midbass would be less likely to have the same heart punching thump on the bass drum beats if it were in the back in the hatch. or if having a 10 or 12 in the same overall enclosure (but braced and sealed and seperated and seperately vented, if vented) would cause problems.

the car is an '03 civic hatchback and I have noticed with my current (way too big) box that aiming up gets me much clearer and cleaner bass than aiming back, I have 500w running to a sub and I could probably have 150w running to it for the spl I want to hear it at, so gain doesnt bother me as much as clarity, though it does sound louder facing up anyways, so I think the midbass in this location MIGHT be amplified cleanly.
 

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You'd have to seal the thing up, including sealing the MDF to the metal so its 100% sealed.

I don't see why it wouldn't work if you did that properly. Usually the metal under the spare tire is pretty thick and sturdy.

Depending on how high you will cross your midbass, I'd keep it in the cabin. (and up front)
 

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Are you talking about having the Midbass woofer using the same airspace as the sub? If so it would sound terrible as each time the sub moved your midbass woofer would move as well. So I wouldn't do it.

Aside from the issue I mention above if you move your midbass to the back your sound stage starts moving back there too. Bass is technically omnidirectional, but the midbass is not, its where your sound stage begins to be formed.

As for the initial question I think you would need to figure out how to seal the baffle you mount your sub to or you'll have the same effect of just setting the sub in your car with no enclosure and no baffle whatsoever. I know that you said using oil based clay to seal, but I'm talking about airtight type seal.

P
 

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Midbass should be upfront, ideally. Think about it, what a sub can't play, your front stage should since you are trying to blend and keep as much bass and midbass up front as you can. Localization can occur if you try to put your midbass behind you.

Also, I think you are actually going to make your work harder by not fiberglassing. Think about it, it will take a LOT more time to seal up everything perfectly the other way, plus if you decide to take it all out, you get to deal with the mess. What's so hard about deadening your trunk w/ RAAMmat or Secondskin, then a small layer of closed-cell foam, then making a fiberglass tub?



You CAN seal off your
 

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Discussion Starter #7
I was thinking of epoxying the baffle or frame (if it must sit up higher than the floor) to the trunk metal, full seal, and rubber caulking as well.

if the midbass were in the rear, it would have its own airspace, NOT share airspace with the sub, basically two enclosures sitting next to each other in the tub. I am thinking the rear because I cant find space up front, at first I thought there was a cavernous area under the shifter in the dash, but its completely filled with electronics, and I dont want to cut into the doors. the rear speaker areas would be ok, but then I would need two drivers, and that increases cost, plus I am only running an 80w single channel, though it may very well be 2ohm stable (or I could get 8ohm drivers) so I COULD run them both off that.

I want to run seperate midbass and midrange because I want my drums to kick me hard, I love that particular aspect of live music and I want my car to do it well, the sub I currently have does NOT do it, and a sub should really be for 80hz and below, doesnt play the drums tight enough. plus, I have a 4ch amp with summed 5th, and will be running the midrange/tweets off the 4ch bridged to 2ch, and I figured that sum channel would work well for midbass since it has its own xover, and the sub amp only has one xover (for two channels that I currently have bridged to mono).
 

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try better mids instead of adding a rear midbass.

putting midbass in that location would require some extra processing. you'd need to cross them low and delay them just right.

and hopefully you wouldn't end up with phase issues between them and your sub.
 

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Discussion Starter #9
try better mids instead of adding a rear midbass.

putting midbass in that location would require some extra processing. you'd need to cross them low and delay them just right.

and hopefully you wouldn't end up with phase issues between them and your sub.
my current plan was the PG RSG in 6.5" for the up front.
I hear what you are saying about the extra processing, which right now I dont have.
 

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This is a job for the DIYMA sub, running about .85 to .9 cubic foot sealed. It will blend with the front giving you the impact missing from your midbass. Alternately and at a much higher cost (though more rewarding in some aspects), the SI Mag V4 would be ideal. It also weighs a bit less so that's a plus w/ a small hatchback.

Basically what I'm suggesting a sub that blends instead of makes itself known. The SI would be more ideal, but a pair of DIYMAs is about the same price so think about that too.
 

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Discussion Starter #11
well if I can trade or sell the current subs I have (2 xplod 12", I am only using 1) then a different sub would feasable. possibly a 10", since I would probably be able to blend the 10" better with the mids, and the box design could extend the response down low.

I've been reading in another thread about how the diyma12" does not like abuse, and sometimes I like to turn up the bass cause thats what sounds better to me at the time, and I am running 500w to it, so I don't think that would be my first choice.

can a 10" sub have a box designed to handle 30-200hz effectively?
 

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I would chuck the Sony subs and get 1 good sub and two good 6.5's mids. Operating any subwoofer up to 200Hz will cause you problems in imaging and probably phasing. If your on a strict budget (if you are maybe tell us what it is) try the ID OEM mid basses/midranges these play low and have some kick. Just remember to properly deaden your doors. As for subs, you can find JL Audio on ebay for less than 50.00 all day long. These are the best for small boxes.
 

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Well lets back up a step. You are saying you are worried about abusing subs...you must keep in mind that your Sony subs are massive steps down from the DIYMA sub and the Si Mag V4. I have a pair of the suckers and I can tell you that with the right box size and a somewhat mindful understanding of what to expect out of the sub, I am blown away. It is truly all relative and if you are used to what I would consider "average" equipment you will be in heaven w/ this sub. 500W in the right size box will not hurt this sub one bit, btw.

To cover the rest...you should definitely deaden and seal your doors, and run some potent front stage components. There's nothing wrong w/ the RSd's you want and they are CHEAP and good, but there is better so keep that in mind. It is a great starting point however.
 

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Discussion Starter #14
Well lets back up a step. You are saying you are worried about abusing subs...you must keep in mind that your Sony subs are massive steps down from the DIYMA sub and the Si Mag V4. I have a pair of the suckers and I can tell you that with the right box size and a somewhat mindful understanding of what to expect out of the sub, I am blown away. It is truly all relative and if you are used to what I would consider "average" equipment you will be in heaven w/ this sub. 500W in the right size box will not hurt this sub one bit, btw.

To cover the rest...you should definitely deaden and seal your doors, and run some potent front stage components. There's nothing wrong w/ the RSd's you want and they are CHEAP and good, but there is better so keep that in mind. It is a great starting point however.
yeah, I am aware that the sonys are junk, doesnt even sound good, got them and the amp in a box for $40.... hate the box, only using one cause I dont need or want both and would prefer the headroom 500w to one speaker gives over 125w to 2 speakers each, hopefully it stays better controlled. anyways, my thought is to sell one of them, keep the other for the wifes car (after I put the bass in mine and she heard, she wants now) and buy a nicer sub. my budget is very very low. as in the materials for the box, (1 sheet of MDF, some clay and epoxy) and the RSD's will be my entire summers budget for my car. we are sorta buying a house this summer, plus getting my motorcycle fixed (dropped a bolt into the front cyl...) cost more than I thought.

so basically, no budget for a new sub unless one finds its way to me, or I can trade both my subs and box for something (we dont have an amp for the wifes car anyways so getting a better system all at once would be better). if I could get $100 for the subs and box online I could buy a diyma12", again I am only concerned about the thread of people blowing them on about the same power when turned up. I have no doubt its a far better sub than my current but that concerns me. I mean if I blow one of my current ones.... well I consider they were free with the amp honestly.

doors will be deadend well enough, clay and some rubber and spray foam, might bump the speakers out a bit so they can have a larger sealed area behind them and face me better, hopefully I can stay within the original grill but if I come out a bit thats ok
 

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Don't worry about blowing it. Just build your box right and you'll be fine. IMO, you're paying more for epoxy and clay than some decent fiberglass. Alternately, you could do the entire box in wood for a DIYMA since you only need a tiny bit of airspace. Think about it, if you are comfortable with wood you could just cut a shape out of that and be good to go. Something to think about...


Also...maybe I missed it but what amp do you have? ohm ratings are going to matter here.
 

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You are talking about another league of stuff here. You previous setup is something that most people buy and install for like 2 weeks before they decide to take it back to walmart.

What kind of amp is it?
 

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Discussion Starter #17
Don't worry about blowing it. Just build your box right and you'll be fine. IMO, you're paying more for epoxy and clay than some decent fiberglass. Alternately, you could do the entire box in wood for a DIYMA since you only need a tiny bit of airspace. Think about it, if you are comfortable with wood you could just cut a shape out of that and be good to go. Something to think about...


Also...maybe I missed it but what amp do you have? ohm ratings are going to matter here.
amp is a rockford fosgate p5002, cd player is a rockford fosgate 9010 (I think thats the model number, it can cross the sum output at 80hz but it cant really do much more processing)

I think what I may end up doing is 2 10" subs, one on each side of the trunk under the rear shelf support, facing down and slighly in. solidly mounted, likely woodbuilt unless I feel spicey then I'd get into glassing them. I'd want to run 2ohm subs so I could get [email protected] out of the amp. I think I would want to run them as vented to extend the low end, and somehow I feel a couple 10's would be easier to blend with mids

eventually I do want to run a cd player with time delay and get them right up front feeling (did that with my old alpine in the previous car and it was cool to hear the sub in the dash when it was behind me)
 

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Discussion Starter #18
You are talking about another league of stuff here. You previous setup is something that most people buy and install for like 2 weeks before they decide to take it back to walmart.

What kind of amp is it?
yeah the subs are very much available from walmart. I basically consider them free with the amp, which I consider a deal at $40. I'm going to try to sell them and the box for at least $50, which maybe I get, maybe I dont, if I dont I'll throw them in the wifes car
 

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You can bridge your RF P5002 to a 4ohm load just as easily as running stereo 2ohm loads. So, you can run either a single SVC 4ohm sub, a DVC 2ohm sub, or a pair of SVC 2ohm, or finally a pair of 4ohm DVC subs.

The DIYMA is the ultimate blending sub, BTW. I understand your hesitation to use it but for $100 shipped you simply can't pass it up. You might also want to consider the new PG RSdc sub, which gets high marks and is pretty cheap.


amp is a rockford fosgate p5002, cd player is a rockford fosgate 9010 (I think thats the model number, it can cross the sum output at 80hz but it cant really do much more processing)

I think what I may end up doing is 2 10" subs, one on each side of the trunk under the rear shelf support, facing down and slighly in. solidly mounted, likely woodbuilt unless I feel spicey then I'd get into glassing them. I'd want to run 2ohm subs so I could get [email protected] out of the amp. I think I would want to run them as vented to extend the low end, and somehow I feel a couple 10's would be easier to blend with mids

eventually I do want to run a cd player with time delay and get them right up front feeling (did that with my old alpine in the previous car and it was cool to hear the sub in the dash when it was behind me)
 

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Discussion Starter #20
You can bridge your RF P5002 to a 4ohm load just as easily as running stereo 2ohm loads. So, you can run either a single SVC 4ohm sub, a DVC 2ohm sub, or a pair of SVC 2ohm, or finally a pair of 4ohm DVC subs.

The DIYMA is the ultimate blending sub, BTW. I understand your hesitation to use it but for $100 shipped you simply can't pass it up. You might also want to consider the new PG RSdc sub, which gets high marks and is pretty cheap.
yeah its currently bridged to a 500w 4ohm mono. I took the second sub out (the enclosure has a divider) and its my storage area since the box takes up my whole trunk space pretty much.

do they make the diyma12 in a 10" ? I like the idea of running 2 10"s now, instead of a single 12. that would allow me to hide them nicely out of the way up in the rear shelf holders/seatbelt supports, and have the amps below them and also hidden, AND keep the spare where it is so I dont have to worry about hiding that in one of the sides. I could still keep the vertical or mostly verticle arrangement of the subs that sounds better than rear or forward facing my car, and wouldnt have to worry about putting wet or dirty things in the trunk.

there is not enough room where I want to put them for 12" subs though.


I was helping someone move yesterday and needed to move the box forward with the seats down, so the sub right behind me and facing me, and with no settings changes, I could not even hear the sub, cabin gain from the rear is incredible on this hatchback
 
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