2 Soundqubed HDC3.0,15's box build ideas and opinions

[Beatin2door]

Hey guys a few days ago I decided to throw out my sub's, amp, and box time for some good stuff. The build is going in a 1994 Mercury Cougar. The sub's and port will be firing towards my back seat, and the baffle will be sealed off from the trunk. I got a very noticeable sound increase doing it this way with my last set up.

This is what I had in mind.

2 Soundqubed HDC3.0 15's

2 american bass vfl4408.1 running 1ohm

250amp mechman alt

2 extra batts (still deciding on what size)

9 cube enclosure after sub's and port installed

I've emailed Soundqubed a few times because I need the overall diameter of the sub to start my build. I'm limited by box width at 38.5 inches and height will be 16 3/8. I'm hoping the sub's will be close to 15 3/4 inches in diameter this will allow me to get at least 133 sq inches of port 144sq inches is recommended with 9cubes. Soundqubed told me this would be fine and to leave my port wall 18inches long, port will be center of subs. I asked for 34hz tuning that's what they gave me for length. Will this be low enough tuning to reach down to the mid 20's hz. I'm looking to get loud who isnt, but I would also like my sub's to play everywhere from say 25hz to 45 or 50hz. If the Ab amps are as good as everyone saysI plan on 2000rms to each sub. I listen to a lot of hip hop. Anyone have any advice or see anything wrong with the setup I plan on using. I'm accepting all opinions and suggestions lol. I really need the overall diameter of the subwoofer though 3 emails later and Soundqubed still hasn't answered that one. Thanks guys

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[Beatin2door]

Oh by the way I had 2 Pa mofo 15s on a hifonics brz2400 8 cubes ported firing forward. I'm hoping s build will be a nice step up from what I had.

 

[Jeffdachef 5,000+ posts]

The diameter is actually a bit bigger than what they recommend, happned to me witb my hdc318s

 

[Beatin2door]

Are you refering to the cutout diameter of the sub? I really need the overall outside diameter with mounting gasket. This way I can figure out how wide I'll be able to make the slot port between the subwoofers. I would fire the sub's up or back with port facing the rear of car, but when I tried firing the subs and port towards my back seats with the baffle sealed from the rest of trunk , it was almost like I had added another amp in the car. I got a big increase in sound, less trunk rattle from the outside of car and I could feel the bass more.

 

[Popwarhomie 5,000+ posts]

9 cubic foot in a trunk??

 

[big scott]

must be 1 big ass trunk.

 

[Beatin2door]

Yes sir 9 cubes in trunk just got rid of my 11 cube box outta there they slide in and out perfect after I took a grinder and cut a 39inch by 17 inch square hole behind the back seat I build them 38.5 wide and 16 3/8 inches tall so they don't get stuck going in I c an go up to 44 inches deep before it takes some work getting them in

 

[Beatin2door]

Hey BigScott do you still have your hdc3.0 15? If so do you know the overall diameter of the subwoofer.

 

[Beatin2door]

I estimated my enclosure volume to be roughly 10.6 cubes before my port and sub's go in. This should give me close to 9 cubes I'm thinking after port and suabs. I estimated the displacement of each sub to .22 I couldn't find the actual displacement , and with a port measuring 14.875 tall 7.5wide and 18 inches deep it should displace 1.4 cubes. I added 1.5 inches to port wall width to account for 2 3/4inch thick port walls. My outside enclosure demensions are 16 3/8 tall, 39 inches across the front, and 34.5 inches deep. Soundqubed told me with 133 square inches of port I would need a 18 inch long port wall for 34hz tuning. Does this sound about right? Here's my problem i can't make my box any wider or taller or its not going to slide in to the trunk from the back seat, I can go deeper. I estimated the woofers to be 15.75 inches in overall diameter and because I need both sub's and port on the baffle this leaves me with a port that can be no wider than 7.5 inches and no taller than 14 7/8 which only gives me 111 square inches of port opening. I know this is gonna affect tuning so I will have to change my port wall length to keep the same tuning and the change in port length will affect my box volume.What effects will the narrower port opening have on the output of the box. I guess I could angle the the front of my box so my sub's are angled slightly towards each other to allow for a wider port between the subs. This would mean designing another box.

 

[Jeffdachef 5,000+ posts]

38.5 width subtract 1.5 and 31-32(sub outer diameter), you only have 5-6 inches to go with. Which is no where near the sq inches of port area per cubic feet ratio you need for anything bigger than 7 cubes net after displacement.

Might want to try a different orientation.

 

[Beatin2door]

I slid my old enclosure back in my trunk today its 11 cubes empty, anyway if I pull it out towards the cabin of the car 4 more inches I can port the top of the box and still have my sub's and ports firing into the cabin, and I cznstill easily seal it from the trunk. I was gonna try and build a slot port across the top and angle it towards the inside of the cabin with most of the port wall out of the box. I think instead I will try 5 6 inch round ports this will give me 141 square inches of port area, I've been reading and some say round ports need less area. If this is the case I can use smaller or not so many ports. I plan to leave most of the port out of the box and I'm gonna angle them maybe 45 degrees towards the cabin of the car. I been using calculators trying to figure out how long they need to be for 34hz tuning in 9 cubes with subs in box. Can someone help me with this? I get different lengths using different calcs. My other question is am I still gonna need close to 144 sq inches of port if I use the round ports?

 

[Jeffdachef 5,000+ posts]

Why not do a 4th order blow through?

Hit up dcarcustoms@hotmail.com give him your max dimensions and he can design you a proper wicked 4th order bandpass that will get down for 10 bucks. Seems like you have the space, just not the clearance. 4 cube sealed and 8 cube ported with the port blowing straight into the cabin.

 

[Beatin2door]

I never thought about trying something like that. I'm gonna take your advice and do it. If all else fails I'll use my last idea lol. What happens if a sub needs to come out. I've seen pictures of 4 orders some of them with ports big enough to crawl into. I'm not gonna give up on this. Thanks for the advice I'm gonna email them first thing in the morning. When I start I will post pictures of the build.

 

[Beatin2door]

No word on the 4th order yet. I got the overall diameter of the hdc3 15 and built a temporary baffle. i need both the subs and the port firing the same way. i want to build a slot port between the 2 subs but i can only get i max height of 14 7\8 and theres 7.5 inches left between the subs. What if i make the port narrower in the center then widen the port at the top and bottom? kinda make the slot look like an hour glass between the 2 subs or some sh** like that. Anyone see any problems with doing the port this way? i needs me some port area yo.

 

[mlstrass 5,000+ posts]

HDC3's don't work well in 4th orders and the enclosure would be HUGE compared to ported....

Will probably end up with port noise doing port like that. Local guy has 2 15's in his trunk set up like that. Burped around a 53, but has port noise on most music when pushing them hard.