Spare Tire Well Air Space...
 

Looking into the future, I want to find out what the total air space capabilities I have utilizing the entire spare tire well area for the enclosure(s). I'll be running a pair of 8's, most likely in separate enclosures which will become the false floor.

I'm still debating on whether I'll be going sealed or ported. That will partly depend on the drivers and amount of air space they require. Most or showing up to 1cf ported, some less.

Many thanks in advance for anyone that may have the air space info!

spare tire well is approximately 2.4 cu ft. I am speaking, of course, of solely the area that the spare would occupy. It is basically wide open under there once you take the foam out surrounding it, as you know from doing your sound deadener.

Thanks! That's a great starting point. If I can or need to, I'll also utilize the space of the foam, all the way into the back corners under the taillights.

I'm either going to go with a pair of 8's ported, OR two pairs of 8's sealed or ported depending on the drivers' requirements.

I've been thinking about this more. With that kind of air space available, the amount of physical room in that area, and I think the floor height is between 8" to 8.5", I could probably comfortably fit four 10's back there and still have them completely hidden out of view, even with the hatch wide open. It would still look like the stock floor.

Several reasons for running so many subs also... A lot more efficient, they move a lot more air, a lot less strain on the drivers, amp and electrical system, much lower distortion from both drivers and amp, and much better dynamics.

It is not to simply be louder, which is not my goal.

What I'm looking at are four Image Dynamics ID10 V.4 D2. These are dual 2 ohm drivers. The two voice coils of each driver would be wired in parallel for a 1 ohm load, then all four drivers wired in series to come back up to a 4 ohm load for the amp.

With typical cabin gain, just on of these would easily hit a very usable 21 Hz in a 0.4cf sealed enclosure. I would have four of them, in roughly 0.55cf each. Loads and loads of oomph.

Possibly even considering a single JL Audio 15W0v3.

BOOM..lol

Nope. Nothing like that at all. Just looking to have detail and dynamics. This is all for keeping the sub as musical as possible.

Well, it's done... I did it now... I have one of these on the way. And yes, it's 15 inches!

http://alpine-usa.com/data/product_images/613_1lg.jpg

My oh my... what a big driver you have there!

Yeah... Something like that...

This is going to be a redonkulous build. :eekdance:

:happydance:

:eek: -------------> :excited:

To be honest, with all of the research I have been doing for the past couple of months, I have yet to find a single 370Z running a 15" sub. Not to mention a Z running a 15" subwoofer completely concealed under a false floor, keeping it looking bone stock.

Attachment 123924

I did a 10" solely for the purpose of mounting depth and 3/4" board

I believe we only have 7.75" of total mounting depth we can use for our subwoofer to be flush with the floor. Any larger driver other than a 12" would make it so that I would need spacers on the top of the box for the sub to fit.

Contemplated doing that with a 15" but the cosmetic aspect of a non flush ported subwoofer just wasn't worth it for me.

Gotta have ported to slam.

Not true at all. You can get PLENTY of slam with a sealed box.

Yeah, that's not true at all. Sealed can "slam" just as hard as ported when done correctly with the right drivers and power.

And speaking of sealed enclosures, my friend decided to start building it today. Just doing a preliminary build with... Gulp... 1/2" plywood!

20 x 30 x 7 has us at 2.23 cf. Once corner bracing, wall bracing, baffle bracing, bracing around the driver opening and driver displacement, we should be in the neighborhood of about 1.95 cf.

He's well into his 70's so he thinks using 1/2" plywood is perfectly fine. I'm just going along with it for now just so we can get the sub in the car before I go on my vacation next weekend and I can get an idea of how the sub is going to sound and perform. Once we're back in town, I'll use it as a base to build the final product from 3/4" MDF.

I'll be going back to his house this Saturday to finish it up.

And today I called off the build of that box. Just the thought of him attempting to use 1/2" plywood was a major turnoff and I wasn't thrilled at all from the very beginning. So I just told him thanks but no thanks. Of course, I was nice about it. He's a great guy and will do anything for you, and he can design and build magnificent furniture, but subwoofer enclosures, not so much.

BTW, that Type S sub came in today. It's a lot nicer than I thought, and a lot heavier too! I don't think I've ever seen the weight of it posted anywhere, even on Alpine's site or in the owners manual, other than the magnet weight of 106 oz. If I had to guess, I'd say it weighs close to 20 lbs, if not more. Nice and beefy!

I'm going to wait until we're back from our trip to install this thing. I don't want to rush into it like I almost did yesterday. I refuse to cut corners with this system, or with the car in general. So it can just sit here and wait until I finalize some kind of plan for it.

As the SI mids and tweets continue to break in, I continue to tweak the levels and crossover. In doing so, there's very little EQ going on. I still need to run the "Auto" T/A and EQ on the new drivers.

I gotta say, these speakers and this amp make for a very clean and clear sound. Though I still need a DSP to get the sound just where I want it. And even though there's zero rattles in the doors, I feel I can still do some tuning to fix that dip in the EQ at the doors with some acoustic treatments of some sorts. There's some kind of peak there that needs to be addressed. The less processing I can do without, the better I always say.

http://charlest.zenfolio.com/img/s/v...95292800-5.jpg


Oh, and the sub came in today. It's funny, I always used to think 15's were bigger than this. It's sitting on top of my JL e110 sub, which is a massive 10" driver. The Alpine doesn't look all that much bigger! It is a rather heavy, beefy driver though.

http://charlest.zenfolio.com/img/s/v...95292801-5.jpg

http://charlest.zenfolio.com/img/s/v...95292803-5.jpg

http://charlest.zenfolio.com/img/s/v...95292802-5.jpg

I had a sub enclosure made out of epoxy resin from some guys here in Austin. I have some pictures here:

Nissan 370Z Forum - dotcomee's Album: Custom sub enclosure/amp install

It sounds really good. It's not completely stock looking but still looks good I think.

Gotta love that big rear end on the Z, plenty of space for an enclosure. :tup:

Nice!

Yeah, with the big booty in these cars, there's quite a bit of available air space back there. I still need to figure out something for mine. I no longer have the tools nor the place to build an enclosure myself. That means I have to either have a friend or friend of a friend build it for me, OR find a decent shop that knows how to build quality enclosures to spec, both the driver's specs and MY specs.

The shop I went to to have the amp and speakers installed, they deal with another guy/shop to build custom enclosures for them when needed. Maybe I should talk to them again and see what they can do for me.

I wonder how much that would cost.

I took some more measurements today. If I were to build an enclosure to fit within the confines of those foam inserts on either side (just where the tire sits), at 19" x 20" x 8.5", that would only give me 1.3 cf of air space, so the foam will have to go. No real point of keeping it all there anyway if I'm not running a spare.

What I think I'll do is have the enclosure as large as possible, extending somewhat into the those rear corners. That will give me the opportunity to mount the sub off to the side towards one of those corners, probably on the passenger side.

It'll definitely be a little bit of a challenge to shoehorn this sub into the car, but I'll get it done one way or another.

As you can see in the pics below, this Type S 15 is a bit larger than the typical 12's installed in these cars... For obvious reasons. :p

http://charlest.zenfolio.com/img/s/v...00375710-5.jpg

http://charlest.zenfolio.com/img/s/v...00375709-5.jpg

http://charlest.zenfolio.com/img/s/v...00375711-5.jpg

I fabbed fiberglass boxes for my Del Sol and 350z in the parking lots of apartment complexes. =)

Feel like doing that again sometime?! Hint, hint... :nutswinger:

LOL I forgot you were local.

I hate fiberglass so much I would charge you more than a professional and do a worse job. =) The beauty of it is that it doesn't require much in terms of tools, etc. Just elbow grease.

The next box I fab will be for my own Z.... been hoping to avoid glass but I think it will end up that way anyway. Have an Alpine Type R 8" waiting to go in and looking to do my first ported enclosure.

Oh snap!

I didn't even notice the fiberglass part of your post. I was rushing on my lunch break and thought you just said "fabbed boxes for"... Didn't even see the fiberglass part. I wouldn't want a fiberglass enclosure anyway. Too much of a PITA.

Nah, for me, I just want to use good ole' MDF.

And now here I am eating my own words...

Just came across an old friend of mine that used to own a car audio shop here in town back in the 90's. He still does a little bit of car audio stuff on the side when time permits, just for fun.

Anyway, I told him what I was doing with my car and that I plan on installing a 15. He offered to build the enclosure for me. All I have to do is pay for the materials and a little for his time. He recommended doing fiberglass. I've seen his work many times in the past as well as hear the systems that he built. He knows his stuff! Several of his systems have competed quite well in IASCA and USACI.

So as of today, the plan is to go with a heavy duty fiberglass enclosure. Since this isn't his main source of income, we have to work around each other's work schedules, meaning it may take a while, but it will be done right.

Once I get the materials (which I can get at or near cost), we'll meet up, he'll mask off and make a mold of the back of the car in a layer of resin and mat, wait for it to cure enough to remove, then I can go back home and leave him with the mold so that he can work on it on his own time.

I'm pretty excited about this!

cant wait to see how it turns out.

Sounds like you have this part covered, but if you end up needing supplies in a pinch there is a local fiberglass supply place. Good prices and selection.

Website:
https://www.fgci.com

You and be both! It doesn't help that I'm an impatient SOB.



Thanks for the tip on the local supply. Probably the most difficult part will be getting the mat, and lots of it. The stuff seems cheap enough though. The resin being the expensive part. Figuring around 3 gallons of it.

I'll be lurking this thread. I want to get 12W7AE-3 into a Z (ported), needs a big enclosure so if you can manage 15" then the 12" should be easy!

Cant wait to see the end results!

The 12W7 doesn't need a large enclosure per say as much as it needs one that's deep. The mounting depth of that 12" drivers is 9 inches! My Alpine 15" Type S is only 7 inches. It requires a max of 2 cf sealed vs the W7 that only needs 1.75 cf ported.

I'll probably actually be going larger than that and end up around 2.5 cf sealed when all said and done.

That would not be an issue at the local shop =) It's actually a pretty gigantic supply place with a huge warehouse and I think they do some manufacturing as well.

This is going to be a slow process at this point.

Researching the types and amount of mat I need and a good supplier at reasonable prices, and being able to find the time to get together with my friend to take measurements and build up the mold of the tire well.

At this point, I do know that the entire enclosure will be thick, heavy, multi-layered fiberglass with a birch baffle. Keeping it solid and sturdy while maintaining a low overall weight is key.

I'm curious; Why are you going so far over the recommended volume for the enclosure?

So I can tune it to my car, my liking. You can always make a large enclosure smaller via stuffing, but can't really make it bigger. Plus, going with a slightly larger enclosure will help flatten the response a bit.

I'm not too concerned with the driver having a lower power handling capability due to the larger enclosure since I'm running a low powered system to begin with and won't be pushing the system that hard. Again, strictly SQ here. Not to mention that a larger enclosure will actually increase efficiency a little.

Seriously considering saying f#@k it and going a different route with the sub build.

This so called "old friend" of mine doesn't really seem to be willing to assist me or guide me as far as what actual materials to buy. I get very short answers from him, if I'm lucky. And as I have been told several times now, 3 gallons of fiberglass resin for one small-ish enclosure is ridiculous. Everyone says that one gallon of quality resin should be more than enough for an enclosure the size I need.

So at this point, I don't know what I'm going to do. I don't know if I'm going to just build a traditional MDF/birch enclosure for it, find someone else who will be willing to build a fiberglass enclosure for me, OR... Say the hell with it and forego the Alpine Type S 15" sub and go with something totally different.

All I know is that I'm getting tired of driving around with only half of a system with no sub(s).

Stick to your guns.. Go the traditional route with MDF or Birch....Much less time consuming, and a better base to build your false floor off of.

Yeah, but that's a lot of extra weight as well. Something I was wanting to avoid. And with the thickness of the wood, the floor height is going to be even higher.

Just some concerns I have bouncing around in my head.