Would have posted this on DIYMA but thought I might get better G35 specific answers here. I know the traditional thought is to keep the subs rear firing into the trunk air space but wondering if anyone's tried firing into the rear seat and what their experiences were.

I'm back to the drawing board on my install (wasn't happy with the 1.0 version) and am up in the air on sub orientation. Unfortunately it's not as easy as "try both and go with the better one" because I don't feel building a 3rd box for testing. The next one I build will hopefully be the last for this car.

Any input would be great, thanks!

 

I would think that the reason people face them towards the trunk is so it can be shown off a little when you open the trunk. If the box is properly built and the sub and amp properly sized I don't think you will notice a difference.

Keep in mind that the wave length of a sound wave the size a quality subwoofer puts out is larger than any trunk. Pointing it into the rear seat might cause some muffling of the sound as it doesn't even have a chance to develop the wave before it has to pass through the leather, padding and metal of the frame of the seat.

 

The low energy soundwave needs "a little" space to develop even knowing that low bass is not directional.
More important for all SQ is that the space is controlled.

Disadvantage:
Rear firing in to center of trunk space has compromise since that soundwave could be performing against a trunk full of baggage, especially on a long trip when you want to enjoy the music. Or as optimum with the empty trunk. But the variability of what effects the low energy sound wave is bothersome regarding predictable SQ and control.

I like my music SQ predictable at home or on the road.

I'm at the drawing board stage too and have made a little progress for the 03 sedan and 10" sub.
I modeled a cardboard enclosure intending to fire rearward.
But now that I have played with trunk space I think I will fire toward the back seat.

Big note here though; I will set-back the face of the speaker 1 1/2" from the back seat to be confident I have not muffled the sound wave.

Opportunities of space for a sealed enclosure are limited, even in the sedan if one chooses to retain maximum compartment size for cargo.

1) The sides of my trunk behind the interior wheel well padding has barely 1 cu ft to fit a sealed enclosure (& irregular panel shapes). Not a good opportunity.

2) My prototype 1.2 cu ft custom enclosure will be built arranging the woofer to fire in to the driver side back seat; allowing 1.5" set-back.

This consumes 15 1/2" of floor space, but leaves a "constant open plenum space" of 1 1/2" x 17 1/2" tall (at minimum) that will not be negatively muffled by cargo.

Advantage: My ears will not be wondering why the music sounds different when the trunk is full or empty.

 

what about top firing? that would provide the most consistent sound if that is what you are looking for

 

/\, Thanks, for best answer yet, top firing is a clean sound wave launch from SQ approach. As a huge advantage as the more compact foot print in the truck space. A simple rectangular tower enclosure.

For (1) 10" sub, it the best space save at 12"x12"x14" tall. Clean and lean.
I'm back to the drawing board.

 

Unfortunately I had to rule out top firing early on because I've got a coupe and I'll be using two 12s, it's just not feasable with the short rear deck. Down firing was also considered but also ruled out because of how deep the box would have to be and the size of it's overall footprint taking up more cargo space.

Couple good responses in here though. I had considered the backspacing away from the rear seat and in this case that won't be a problem. The subs I'm using are the old Illusion Audio carbons with the front mount magnet so even if the magnet is touching the seat (which it wouldn't) the woofer is still about 3/4" away from it.

As for the first response about showing off the subs, due to the front mount magnet it's tough to do much for a grill without fabricating your own and I don't actually want to draw attention to it everytime I have to get something out of the trunk. If I wanted to show it off I could always just drop the back seat.

Anyway, still not decided but good points made so far, wouldn't mind hearing from anyone who's already tried this in a G.

Thanks guys

 

Ouch (2) 12's. amps, etc, Coupe trunk. Can't sneak it in?
I think your firing at angled face 1 1/2" and parallel toward the back seat.
You'll need the full height of the trunk space for enclosure volume to be reasonable. Probably stick to sealed box sizing. Good luck

 

Yeah, I've got no chance of legitimately making the 1.2cu (each) but I'm going to fudge it as much as possible with polyfill. Overall size, before you start notching out a couple inches here and there to make the floor of the trunk part of the enclosure is about 41" wide x 20" high. Top depth is negligible, maybe 4"+ and bottom depth about 9". I'm figuring the max airspace I'll have inside the box is roughly ... well now that I've done the math not enough for polyfill to cheat. I think I'll back the rear panel of the box up a few inches to be almost even with the rear windshield, since I'm not firing into the trunk anyway I don't mind not having them vent into the car through the 6x9 openings. That'll give me a bit more width than the previous 41" but if I keep it there to maintain a normally shaped box I'll get a top depth of 12" and a bottom depth of 16" (keeping the height right around 20") for an internal volume of somewhere near a cube each? I'm not sure that's right, anyone good with math help me out there...

In any case I think I've just decided on the seat-firing subs unless someone talks me out of it before I start building and fiberglassing this weekend.

And to edit: I'll be using two pieces of MDF for the front and rear panels of the box, the backseat side (where the subs will mount) will have an additional 3/4" MDF trim ring inside the box which I'll mount the subs to before sealing up the rear panel. I plan to use fiberglass to form the top, bottom and sides to keep it sealed and deal with the odd contours that pop up here and there. The subs are so narrow that their overall displacement doesn't amount to much and really won't mess with the interior air space too much.

 

i was in the same sitation you are in more or less ( i didnt care which direction it faced).

i put 2 tens and 2 amps in my trunk. HOWEVER , i did 2 custom enclosures for the sides of the trunk. i can send a pic if you want. if youre willing to put in the time... id do that. its not the most difficult to do, just difficult to make look pretty and sound the best. but my first time using fiberglass and im quite pleased with the sound. granted, i only need .6 cu ft each, not 1.2. . i also had them slightly facing forward towards the front of the car, and i get almost no rattle when i blast my music . i can barely even hear the music outside my car when im blaring it to where it hurts my ears on the inside, and i only dynamatted the doors.

my other thought for you, would be to make a big @ss box that goes against the back of the seat, like a 1080 or 4080 i think it is enclosure. it would like like 3 ft wide (entire back seat opening), and possibly a ft or 2 deep (deep enough to get the size right), and high enough to just miss the 6x9 rear deck, or honestly if your not using 6x9's, you could build it higher and less deep.

now you would mount your amp(s) on the back of the box. Back to your question of rear facing or front facing. whenever i see crazy audio set ups, they almost always have the subs directly against the back seat facing the front of the car. it may not sound the best/look the best from the trunk, but my guess is they do it for a reason. besides the fact that it protects them from roling things in your trunk. however, then your amp would be trunk facing, and to remedy that, i would throw either a custom cage around it (like a grille cover), or if you wanna go nuts, build it into the box with an acrylic enclosure unit.

just my 2cents. Good luck and take pictures !!!

 

also, i jsut read your last post before i wrote what i did, but if you havent started, mabye itl give you some more ideas. PICTURES

 

hdmark, thanks for the feedback man, would love to see pictures anyway but the ONLY reason I didn't want to use the rear most corners for the enclosures is that it'd be damn near impossible to get a set of golf clubs in the trunk if I did. I wanted to keep the widest part of the trunk open for that purpose. As far as what you said about building against the back seat, that's exactly what I'm looking at. It's actually 41" at it's widest point (and a touch over 20" high with the 6x9s out, which will stay out) if you go from the brackets that could hold a rear strut bar - which brings me to a nice secondary effect of building something there, if the box is stiff enough and fit tightly enough, it MIGHT (I don't really know yet) actually help the stiffness of the rear half of the body. I say that because the RareJDM and GTSpec rear bars use the brackets that I used to measure the width of the potential box.

Anyway, post up pics for the helluvit, would love to see what you did.

 

I'm going back to my first concept to retain max trunk floor space and sub bass SQ.

The simple rectangular shape "up firing" model, without the angular side, still kills trunk floor space in my sedan because of the 67 deg angled back seat constraint.

I need to be parallel to the seat and fire at it, to retain floor space.

I'm back to the forward firing (1 1/2" set back from back seat) full height box design.

For the Alpine 1042 10" single sub the custom sealed outside box dimensions are :
width = 15"
full height 03 sedan = 17 1/2"
67 deg angular sides = Top 4 1/2" with bottom 11 1/4"

net internal volume (3/4" MDF) = 0.80 cu. ft. (meets Alpine OEM requirements)

the center of the woofer mount position is offset slightly toward the bottom to clear internal walls.

 

Hey Toro, in your circumstances you could still make the up firing work pretty easily. Build the box's external specs to match the contour of the seat and use some fiberglass internally to smooth out the odd bottom half. Could very easily end up with sort of a half-eggshell lower half that wouldn't hurt sound a bit if you add the material inside it.

Hell, go one further and make a shallow(ish) box hung from below the rear deck! It'd be a wide narrow rectangle but if it was suspended from the rear deck and still upfiring how sick would that be? And how much trunk space would that save!?

 

I'm finishing up a design for my 2 Digital Design 1508's and the build will be starting next week. The design is a 4th order bandpass that will fire into the ski pass via a square .5" MDF port which will be 6 3/4" long. The top of the enclosure will sit evenly and against the top of the seat in the trunk. The rear baffle will have 3 plexiglass windows. There will be 6 1/4" clearance below the enclosure for my amp rack and extra battery. There will be trim pieces made to create a wall for cosmetics.
I'm anxious to get this project started. I will start a build thread when I start so folks can stay tuned.

 

Tennessee, looking forward to seeing the finished product, should be a fun project! What thickness plexi are you using (and how do you plan to cut it)? I messed with the idea of a plexi wall on my box, then the possibility of an insert, but I think I'm going to pass, which is a shame because the basket of my subs really should be displayed, they're pretty