6th order dual reflex bandpass | Trunk wall | Two 15" HDS215s | 15

[Chad McCormick 1]

Okay guys, I thought I'd share my most recent build with yall. I work until 5:00 P.M. so please excuse the low light pictures. Most of the work was done at night. Ask me questions so I can make this a more complete build log! I wanted to put this here for SoundQubed, but if a mod thinks it needs to be moved to the build log section, then feel free to move it.

 

Equipment: Two HDS215s, JBL GTO 1400.1 amplifier (1500w RMS @ 2 ohms), XS Power D3100 battery, Alpine CDE-123 head unit, Sky high 10ga wire for subs and 1/0 for power and ground. Stock alternator, and I still haven't done the big 3... I need to get around to that.. But my light dimming isn't too bad with this battery on only 1500w.  

 

 

Rear chamber is very close to 6.3 cubes after displacement of port, and a small guess on how much fiberglass displaces. Front is an educated guess of 2.8-3 cubic feet.

 

Rear is tuned to 35hz, and front is tuned between 70-85hz. It's kind of a guessing game using the ski hole as a port.

 

This picture was really taken after my first botched attempt, but it lets you get the breath of the trunk before.

 

After some tinkering with cardboard, I got the shape of the interior where the wall will go and then cut this.

 

Then carpeted it.

 

And threw it in. It damn near fit perfect the first time. I only had to make some very small mods to it.

 

After getting it in, I sealed around it with "great stuff" to create a solid seal. I also had to build the box inside the trunk because of how large it was, so L brackets were also required.

 

Angle grinder to cut an 8" hole in the deck for the port.

 

Port hole

 

Port hole

 

After the floor was on, the walls went on relatively easily.

 

 

 

 

 

 

I fiberglassed all of the corners for extra support and a better seal.

 

Some seriously perfect timing, my subs came in on my lunch break!

 

So sexy.

 

This is how I created the second chamber for the 6th order.

 

I went a little foam crazy, but you get it. Sealing all the holes up makes this an additional chamber in front of the subs, and the ski hole becomes the second port. (specs, tune, and cubic footage at top.)

 

Fix up the back.

 

Bulked up my electrical a little bit.

 

Seats back on. Hey you little SoundQubed! I see you peeking at me through that hole!

 

 

And that's it guys. Total cost for subs, box/building material, and battery was about $570. Subs were $105 a piece, battery was $225 used with the terminals, and building material was about $135 for everything. I already had the amp and wiring, so I didn't have to buy that.

Edited August 8, 2014 by chad_m

[Notorious97200 339]

Nice !

I don't see so often 6th order bandpass boxes. How does it sound ? Are you satisfied with it ?
 

what do you have for mids & highs ?

[Chad McCormick 1]

Nice !

I don't see so often 6th order bandpass boxes. How does it sound ? Are you satisfied with it ?

 

what do you have for mids & highs ?

The only mid/highs I have are the stock 6 1/2" + tweeter Bose that came with the premium sound system for the car. They actually sound really good. They all have their own individual amps, and I hear they run @ 1 ohm. That is word of mouth on the Maxima forum though. Not verified. All I know is that these subs are loud as shit, and I can still hear my front stage very well. That is why I haven't swapped them out.

 

The subs themselves sound great. (surprisingly) Much better frequency response than I thought it would have. After 35 or so it drops pretty rapidly though. Below 30ish is basically useless. I have always gotten better results firing backwards into the trunk, so I was a little hesitant to go with this design, however I am quite satisfied. If all the stars aligned, on a windy day, I could probably pull off a small hair trick.

[Chad McCormick 1]

Oh! Another thing I love about it, it is quiet as hell outside the car! Virtually zero trunk rattle!

[osiris10012 8]

Sweet looking build!

[Chad McCormick 1]

The bass sounds so much tighter. I'm not sure if that's a trait of 6th orders, or the subs. It sounds so much cleaner all the way up the volume knob. I was afraid to turn my Type R over 20 because it started to sound distorted. I feel perfectly comfortable turning these up to 25 or so easy though. It sounds fine all the way up there. Tones that use to be virtually inaudible with my Alpine SWR-12D2, now hit you hard in the chest. And other songs that I remember hitting hard on the Type R are surprisingly underwhelming. Still better than the R, but it's obvious that my gains did not occur across the board, I did lose in some areas, which I know to be a trait of 6th orders. The higher tuning may also be attributing to that. I might change out the port to a longer one and see if I can tinker with it a little. Not because I am disappointed, quite the contrary, I just want it to be the best it can.

 

After further thought, the "tighter bass", "cleaner sound", "higher power handling", could be attributed to the box being too small. I originally planed for both subs to get about 3.5 cubes, but one thing after another led to this being the final box.

Edited August 8, 2014 by chad_m

[SoundQubed 20]

This looks great, bout it sounds awesome too!
Enjoy.

[dharris2488 1]

Creative man... would love to listen to it!

 

Entry level... I love it!  I remember when I got my first set of HDS3 12's and a Q2200.  My mind was blown to say the least!  I have a similar style trunk.  Wonder if I could pull off something like this with the HDC3 10's? Hmmmm