Box Help

[Dmurria 10+ year member]

Ok I'm designing my own box using Google Sketch up and Re Box Calculator, I'm making an box for 4-18" Fi BTLs and was wondering could I have the Tuned Frequency at 20Fb for daily use. I'm going to be using it at shows and was wondering if it would be loud. If it helps its going in an 2007 Expedition EL Firing upward. I dont want to wall it because I'm like being able to look at the rear.

Click to read more...

 

[bgowdy 5,000+ posts]

good choice for the box design. but that may be a bit low. if it were m & this is only IMO i would go about 31. so are you going to be competing in spl?

 

[Dmurria 10+ year member]

Also I'm going to powering them with a Hifonics HFi3000D one per subwoofer, wired at 1ohm.

 

[Buck 5,000+ posts]

Ok, please don't use RE box calculator for a setup of that intensity, that would be a disgrace. It's not as accurate as I'd like it to be.

 

[bgowdy 5,000+ posts]

i use 12volt.com... its actually very acurate... nice amp choice. ive been told they are a tad bit over rated. but not by much. but yea id still say 31

 

[Buck 5,000+ posts]

And don't tune to 20hz, lowest I would would be 26, but I would do 28-29 hz.

 

[Dmurria 10+ year member]

Why shouldn't I tune to 20hz or use the RE calculator

 

[RAM_Designs 5,000+ posts]

Why shouldn't I tune to 20hz or use the RE calculator

The sub just isn't made for a low tuning like that. Tuning that far below the sub's fs is going to cut your box efficiency. Unless you plan on playing only stuff in the 20's, there's no need to tune that low. Keep tuning in the 30-33hz area and you'll be able to dig down to 25hz with those subs, which is plenty low for pretty much any music. Also, you're going to need more than a single layer of MDF on this thing, and ample bracing as well, something that the RE calc can't take into account for.

 

[Dmurria 10+ year member]

Ok thanks, I'm going to tune it to 29Hz. The box is going to be 7ft3 for each sub, with an double baffle. How do you get a mirror finish with out using fiberglass

 

[MisterDeadeye 10+ year member]

How to Get a Mirror Finish on Wood | eHow.com

 

[RAM_Designs 5,000+ posts]

Ok thanks, I'm going to tune it to 29Hz. The box is going to be 7ft3 for each sub, with an double baffle.

You're going to need to at least do doubled 3/4" material on the entire box. A big, low-tuned box like that will want to tear itself apart if not built right.

 

[pro-rabbit 5,000+ posts]

You're going to need to at least do doubled 3/4" material on the entire box. A big, low-tuned box like that will want to tear itself apart if not built right.

exactly, if you don't want to use twice the MDF you can do other types of bracing, but you need to be sure to do it right or you will wind up with a broken enclosure very quickly.

 

[audio-pro714 10+ year member]

28 cubes and dbl mdf and he still wants to see out the back?