87 GMC stereo dilema, Help! Need some more ideas!

[cmax87v3500]

So I have a 1987 GMC V3500 Sierra Classic standard cab, as of now I have a custom sub box with 2 kenwood shallow mounts in it, and it works good with the factory seat, and is only one notch forward of all the way back(yes i know it makes marks in the back vinyl of the seat, but it does not affect the sound, or subs, and does not bother me) I included some pics of how i have it set up now. but i have a bench seat out of a late 90's GMC that has the fold down center console, like the one in the third picture that i would like to install. (That's another GMC k3500 truck my father built). I am afraid after taking measurements and just doing some guesswork it will cram me too far into the steering wheel to be comfortable (I'm 6 feet tall, but like my leg room). i'd really hate to loose the stereo with the seat upgrade, but really want to install the new seat. One of our friends just bought another k30 my dad built, and we measured behind the new style seat in it, and with it reclined comfortably, and slid all the way back there is 2 inches at the top between the back of the seat, and the back panel of the cab beneath that rolled out area, and 7 inches at the bottom from the bottom of the seat to the back of the cab. Ive done the work and figured out i could fit a jl 13tw5-3 in a box that size, but i cannot afford those and they would not work with my amp due to the ohms being too low for it to be stable(kicker ZX700.5). Any ideas on how i could make the seat work, but keep good bass and not loose sound quality. or even better, use the subs i have now Thanks, this is my first post and appreciate any help available!

[4ofakind]

cmax, you gave us SOME measurements for the new seat, 2" @ the top and 7" @ the bottom. What is the total height? What are the dimensions of the current box behind your old seat? It looks to be bigger than 2" @ the top. What is the model number of the kenwood shallow mounts? Worse case cenario is you will have to build a new box behind your new seat for your current slim woofers.

Mal

[cmax87v3500]

well the subs are Kenwood kfc-xw1200f's, the box is 15 inches high i believe, whatever the height from the sheet metal on that shelf in the back area of the cab, to that rolled out area is, 4.5 inch top width, and 6.5 bottom width. the bottom could be 7, but unlike the new seat it would hit the plastic hinge covers. its made of 1/2inch MDF. the width is of no concern because I'm pretty sure ill be able to fit 2 subs between my 6x9 cabinets, unless their like 28 inches wide. the box is 54 inches wide now, just so you know. i wont build a box that goes higher than that rolled out section, or lower than the flat area back there, and i wont alter the cab in any way. il check on that heighth measurement asap. i appreciate the response!

[cmax87v3500]

yup, 15 high, but 55.5 wide.

[4ofakind]

Downloaded the owner's manual for the Kenwoods and per THEIR recommendations (Sealed: 4.25" Top x 6.25" Bottom x 14.25" High x 30.5" Wide for .8ft^3) they won't fit behind the new seat. Your problem is at the top. Boxes do not have to be built exactly to manufactures specs, but 3.25" is a significant change w/o adjustment elsewhere.
You said the new seat will be back as far as possible, could you reduce the amount of recline a little; sit more straight to get another inch up top?
Maybe someone else could offer another suggestion barring getting the 10" Kenwoods as opposed to the 12" ones you have.

Mal

[cmax87v3500]

ya, ive thought about that, sadly, i don't know what the measurements would be with the seat tilted farther forward. ive drawn up box diagrams with a 7 inch bottom, and 2, 2.5, and 3 inch tops. i know there are two other brands of subs, jl, and power acoustik that make super shallow subs(the jl is 2.5, and the power acoistik is 2) but they are the two extremes. the jl is super high quality and 4-600$(each!), and the power acoustik is comparatively lower quality, but 75 bucks lol. the new kenwood xr-w12f is a little shallower at 3 7/16, the xw-1200f's are 3 15/16. may be an option to get a little more room. i believe i figured the xr-w12f would fit in either the 2.5 or 3 inch top box i drew up, which i believe wouldn't be too bad. the new seat has locking reclining seat backs too so i can lock them at the angle i like, the cram them back into the box(sounds kinda bad lol) without the seat backs flipping forward like the factory seat does if crammed back.

[tubbedII]

If it were me, I'd just build the box to fit what you got right now. Without the speakers and building a wedge box that's 55.5" wide, 15" tall, 2" deep on top and 7" deep on bottom you'd be at almost 1.6 ft^3 of volume without the subs. Then stuff it full of polyfill and hope you still like the sound. Worst case scenario is that you don't like it and have to pull apart the front face for different speakers, but if you really want those seats with the most room, the rest of the box is what it is and can't really be modified so not much lost other than time and a face plate...

If you do this, just be sure to measure that the subs will fit 1st since the top is so shallow and may hit the back of the enclosure.

[cmax87v3500]

ya, i just made a cut out of the profile of a kenwood xr-w12f and put it on the side profile layout of the sub box i need for the new seat, and i think they will fit,it will be close but i believe it will fit. the subs only require .8 cu ft recommended so its technically perfect according to kenwood. the cutout is as close as i could get from the limited dimensions the manual gives, but i made it a little big on all sides so there's room for error.its close on the back edge, less than a quarter inch, but it seems like it would work. thanks for all the advice. hopefully within the next few weeks or so ill be able to figure it out and build the box and install the new seat and be cranking the tunes! but either way theres nothing wrong with just messin with the ol truck Thanks Guys for all the help and advice!

[4ofakind]

Originally Posted by cmax87v3500

ya, i just made a cut out of the profile of a kenwood xr-w12f and put it on the side profile layout of the sub box i need for the new seat, and i think they will fit,it will be close but i believe it will fit. the subs only require .8 cu ft recommended so its technically perfect according to kenwood. the cutout is as close as i could get from the limited dimensions the manual gives, but i made it a little big on all sides so there's room for error.its close on the back edge, less than a quarter inch, but it seems like it would work. thanks for all the advice. hopefully within the next few weeks or so ill be able to figure it out and build the box and install the new seat and be cranking the tunes! but either way theres nothing wrong with just messin with the ol truck Thanks Guys for all the help and advice!

That was a great idea! Why did you need our help again ? Seriously though it looks like that will JUST fit. Too bad you could not keep the woofers you already have. But these should be a nice upgrade.

Mal

[cmax87v3500]

My dad worked in a stereo store for a long time, until 1991 when he went to work at our local GMC dealership, so i have the know how, i just wanted some input from other people, i didn't want to be one of those guys who just assumes he knows the best idea. thats never a good way to be. and ya, i wish i could use my subs, but i need that extra half inch. they may have better low end sound due to the 25% bigger cone, at least one can hope ha thats all the two i have now lack. if i had the money id buy those JL audios, but the new kenwoods are only like 60 bucks or something more than the ones i have were (instead of 450 more haha). so ill try to hopefully sell the two subs and the box, for close to how much i can get 2 new subs for thanks again for all the help. if anybody finds any new shallow mount gear or anything cool and remembers this post let me know!

[tubbedII]

Great job on the cut out! Seriously doesn't look like you need any help...

Originally Posted by cmax87v3500

the subs only require .8 cu ft recommended so its technically perfect according to kenwood.

However, this statement isn't really true. The box is a little less than 1.6 ft^3 WITHOUT the speakers in it, so once you drop the speakers it will be taking up some volume which is why I said to stuff it full of polyfill. Polyfill is supposed to trick the speaker into thinking it's in a larger enclosure than what it is. It's pretty close and .8 ft^3 is their maximum recommendation so it shouldn't affect it too much...the only problem is that it's in a bigger box right now so you might notice a difference.

[cmax87v3500]

ya polyfill was in the plan, and i see you point, hmmmm well i think itl be close enough, gunna have to be i guess, ive read a review on the xr-w12f and the person says hes got it in a .68 cu ft box and it works good, and he dosent have polyfill so??? hopefully it will work out ok lol thats the bad part about truck like these, just no room in them lol but gotta work with what ya got. idk if you knew im using 1/2 mdf, im not sure how much of a differencein volume that would make over 3/4 or something. im not any good at calculating the cu ft stuff lol ill post pics of the build and seat/ sub install if and when i get there. thanks again everyone!
-Clint

[tubbedII]

Me neither! Haha...I use a 12volt.com's calculator and put in that it was 1/2" mdf

http://www.the12volt.com/caraudio/boxcalcs.asp

[cmax87v3500]

thanks for the resourse, thats works great!

[Billett]

the12volt.com is an awesome website. all kinds of nifty things there. When I built my box I used 3/4" mdf because its just that much more solid, but since it looks like you are tight on space and the shallow mount subs won't hit crazy hard the 1/2" would definitely be enough. Design looks great though, can't wait to see it built

[cmax87v3500]

the box they are currently in is 1/2 inch, and surprisingly they actually hit really hard, as hard as a set of full size kenwoods i had in my previous blazer, but this box has held up for a couple of years so hopefully the new one will too. still waiting on time and funds to clear up to do some more work on the ol truck. Thanks!

[Billett]

Whoops didn't even check the date on the last post haha. Well I'm glad the box seems to be working out for you. Don't suppose you have a finished picture?
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[cmax87v3500]

well as of now the original photos are still whats in the truck, with the original seat. i haven't had the time or money to do anything with new subs or new box, so i just stuck the new seat in my loft and am enjoying the truck as is for now. ill definitely post up some pics here when i do though.

[E.Furgal]

it might sound better with one sub.. as you'll have a bigger box.. volume