Need advice on my latest ideas....

[waltham415 0]

So I come today bearing questions... I have two ideas for a system and really am at a standstill and could use some advice. Both ideas will be forward firing with the truck sealed off from the front. My first idea is two 12's in a sealed box. Due to the fact that the max height in the trunk is 12.5in, I would have to tilt the sub back to make it fit, and for the sake of visuals, tilting them inward at the same time. I would prefer this setup, but due to limited resources, I'm not sure if I could cut any mdf with the angled edges required to achieve this. So this leads to my second idea... If I ran two 10in subs, I could run them straight up and down, and I could port them. I drew up some ideas but have not yet figured out how to upload them...

So now with the questions.... Is there a way to cut the mdf to achieve these angles that I am not aware of? I would prefer the two 12's but would be happy with either idea. When sealing off the trunk, could I fiberglass from the subs to the frame behind the seat to achieve a decent seal? With the subs fairly close to the back seat, would that cause a loss in sound for any reason? and finally, a personal question, which method would you use?

Either way, the subs will either be SKAR VVX's or SSA dcon's ran (for now) a 500wrms alpine amp.

Any ideas, advise, criticisms, etc. would be greatly appreciated.

Thanks

Alex

[trod2902 26]

what will you be using to cut the wood?

[imsolost7886 1]

i'd do the 2 10's ported, its going to be much less work build wise. being ported, the low end will seem louder, and you're really not sacrificing a ton going with the 2 10's ported instead of 2 12's sealed.

[///M5 2,833]

All depends on build skills. Installation >> equipment so you don't want to screw that up. Oh, Dcon >> Skar based on the company alone that's a no brainer.

[waltham415 0]

I do realize that everything is so dependent on installation, and being that I have never done any real woodwork and have a table saw and skill saw at my disposal, I want to give this a shot, but I'm worried about screwing something up. I'll probably go with the two 10in DCON's ported. I am going to build the box first so I have no excuse (money) to put off getting this system under way.

I may need a hand getting the tuning of the box right. I'll be running the DCONs off a 500wrms alpine monoblock and would like to hit the "optimal" 1.25ft^3 mentioned on the website tuned to ~32hz. My maximum dimensions are 30" wide and 12.5" tall, it can go as far back as needed. I know the table saw's blade can be tilted 45 degrees so I would like to have 3 front panels, the middle flat, and the two sides facing inward at that 45 degree angle. The subs will be mounted on the sides and the port in the middle panel. I can try and run some numbers for such a box, but my design skills are a bit underdeveloped so if anyone could pitch in I would be obliged.

Thanks for the advise and any more to come in the future

Alex

[///M5 2,833]

Why the 45's?

[Impious 1,476]

If this is your first attempt at an enclosure, I would keep it simple.

[waltham415 0]

Yeah, I guess that would be a good idea. The 45's were strictly for astetic purposes and I wanted something unique, but I probably shouldn't go for too much my first go around. Also, getting rid of that, the designs should be fairly simple and widely available from other topics. Now I just need to figure out how to seal the trunk off from the cabin... Maybe even that would be too much work but I just like the look and sound. Ever since I saw EmperorJJ1's cobalt build log I have wanted something like that in my car. I have already taken my back seat apart once and found that it should be possible, but whether it's do-able for a first time fiberglass experience......I hope to find out

Thanks again

Alex

[waltham415 0]

Went with the square box and used the RE calculator to come up with this design, but I've read mixed reviews of this tool so could someone just check the math for this one? the box will be 30"x21" @12.5" tall. The port would be 11" tall, 3.5" wide, it would go in 16.75" and then 11 more inches after the turn. According to the website, this results in a 2.77ft^3 box tuned to 31hz. the DCON 10's will take .2ft^3 ending in the "optimal" 2.5cuft volumn listed on this website. Here is the dimentions it recommends if that's easier to check.

Bottom Plate: 30 x 21

Top Plate: 30 x 21

Left Plate: 20.25 x 11

Right Plate:19.5 x 11

Back Plate Front Plate: 30 x 11

Port L1: 16 x 11

Port L2: 11 x 11

Does this look right?

Thanks in advance

Alex

[sefugi 166]

Not saying I know everything about enclosure builds but those specs seem to have a higher tuning than you originally wanted. The RE calc. has been said to tune higher than it states. I'm showing that with those specs you will have a tuning of around 38Hz. You can use this sire to do a little checking on your port info.

[Luke.H 33]

Went with the square box and used the RE calculator to come up with this design, but I've read mixed reviews of this tool so could someone just check the math for this one? the box will be 30"x21" @12.5" tall. The port would be 11" tall, 3.5" wide, it would go in 16.75" and then 11 more inches after the turn. According to the website, this results in a 2.77ft^3 box tuned to 31hz. the DCON 10's will take .2ft^3 ending in the "optimal" 2.5cuft volumn listed on this website. Here is the dimentions it recommends if that's easier to check.

Bottom Plate: 30 x 21

Top Plate: 30 x 21

Left Plate: 20.25 x 11

Right Plate:19.5 x 11

Back Plate Front Plate: 30 x 11

Port L1: 16 x 11

Port L2: 11 x 11

Does this look right?

Thanks in advance

Alex

I didn't check to see if that was right, but I've heard the same as Sefugi about the RE calculator. The12volt has some handy calculators to use to help you design one yourself if that's the route you're wanting to go. If not there is always lots of people on this forum who offer box designs

[waltham415 0]

So I tried running some numbers and now feel rather stupid.... when all of these calculators ask for the box volume, does that include the volume of the port? Am I suppose to subtract the volume of the port from the box volume (or even the volume of wood needed for the port) before I even know the length of said port? Chances are I am missing something really obvious here so any help would be greatly appreciated.

Alex

[shizzzon 461]

yep, in order to use calculators, it needs to know the NET volume of enclosure only.

Example-

u have a 5cuft box...INTERNAL

inside, the port takes up 1 cuft and the sub takes up 0.3 cuft

So the actual internal NET volume is 3.7cuft and that's what you'd use in the calculator.

[cobra93 47]

If you decide to tackle the 2- 12" box and the angle cuts, you have the necessary tools to do so.

I'd draw the box out, looking top down and from the side, on a piece of wood big enough to check yourself before you make any angle cuts, use it as a guide.

Do all of your pieces to size, then miter them to what you need, if you're unsure.

If you mean to do compound miters and you're new to this, go with the 10's.

Edited June 8, 2011 by cobra93

[waltham415 0]

Alright, after discovering a new downloaded port calculator and google sketchup, I think I might have another box idea. The outer dimensions are 30" x 25" at 12.5" high. The port is 4" wide and 11" tall and stretches in some 42 inches. This should leave a 2.5cuft box after the port, subs and bracing. According to the calculator, this results in a tunning of a hair under 31hz... Does this sound right?

Top/bottom: 30 x 25

sides: 25 x 11

Baffle: 24.5 x 11

Port 1: 19.5 x 11

Port 2 19.5 x 11

Sorry for all the questions but I'm am rather new at all this

Thanks

Alex

[waltham415 0]

This is a bump and question. I plugged in the sub/box combination into WinISD and got an odd looking curve that hits -2db at 56hz then moves up to +1db at 32hz. Again the question is just does this all sound right. First build.... don't want to screw it up too bad....

Thanks for all the help.

Alex