Advantages & disadvantages of this box; help?

[jolly_26 10+ year member]

Summers coming up so it must be time to build a new box for roadies. Got two 12s, hoping to tune to 32Hz, and would prefer a box where the subs cannot be easily reached by luggage. Had a thought and so quickly mocked it up on sketchup, and here it is.

Also, not entirely sure how this attachment tool works so you might have to give me a while to upload these pics elsewhere if it doesn't.

Click to read more...

 

[jolly_26 10+ year member]

Well seeing as the attachments worked I may as well start us off

Pros; inconspicuous, subs not likely to be damaged by anything my mates throw in the boot, something different, subs should get a fair bit of loading going on for a decent SPL

Cons; how do I get the subs in there?, would have to be large as I don't have the advantage in having 2 12s in say 3 cubes, i would have to have maybe 2 cubes each, would be pretty heavy, could potentially be difficult to design well with a good tuning and range.

 

[TheUnderFighter 10+ year member]

Well one thing I'd say is if you wanna save space, I'd go with a pair of 10's, you don't give up much cone area there. Unless you already have your subs then never mind. And another thing is with subs facing each other like that, I've heard there are possibilities of cancellation issues. but someone else will have to weigh in on that, I really don't have much experience with it.

 

[jolly_26 10+ year member]

Well one thing I'd say is if you wanna save space, I'd go with a pair of 10's, you don't give up much cone area there. Unless you already have your subs then never mind. And another thing is with subs facing each other like that, I've heard there are possibilities of cancellation issues. but someone else will have to weigh in on that, I really don't have much experience with it.

Yeah as far as I know you will only get cancellation issues if the subs are out by 180, right?

 

[dumple 5,000+ posts]

summer? its october?

 

[Chriszle 10+ year member]

summer? its october?

OP is in New Zealand...

 

[UnderFire 10+ year member]

I don't really know much about this but, wouldn't you get some strange **** going on since the sub fires into the port area?

 

[hispls 5,000+ posts]

I think that might be a problem. If your main issue is just not smashing the cones with things you throw in your cargo area try proping the box up on legs and firing subs down. This looks to be some sort of complex bandpass. If you don't really know what you're doing, chances are it won't sound good.

 

[FtheNutHuggers]

it would operate like a severely misaligned series tuned bandpass, with three high-tuned chambers. you also will likely have a tapping effect to account for. no good.

 

[jolly_26 10+ year member]

it would operate like a severely misaligned series tuned bandpass, with three high-tuned chambers. you also will likely have a tapping effect to account for. no good.

I was planning on having quite a bit more space between the subs firing towards each other; 300mm or so, but once I threw the dimensions in sketchup I realized I didn't have the space for it, and the sketch turned out this, so thought I'd see what you guys thought. Probably way too difficult by the sounds of it, so thanks for letting me know.

I think that might be a problem. If your main issue is just not smashing the cones with things you throw in your cargo area try proping the box up on legs and firing subs down. This looks to be some sort of complex bandpass. If you don't really know what you're doing, chances are it won't sound good.

Would that cause a significant drop in spl or not too much? and in which direction would you recommend firing the port?

OP is in New Zealand...

**** haha was hoping to cause a solid five or six posts of confusion, it would seem you car audio guys are more intelligent than most forum dwellers

 

[Jroo 10+ year member]

I was always told you could never fire two subs together like that. No matter their phase, they will cancel each other out

 

[Z1NONLY 10+ year member]

I have a hard time visualizing what the air is going to do. I know it will eventually exit where you want it to, but it looks like a messy free-for-all before that happens.

The "main" slot seems like a port that's being fed from 2 different points along the port and two different methods.

I'm not saying it won't work, but if it does, I can't account for all the factors at play here with any accuracy.

 

[i2ain2thunder 10+ year member]

Add some sealed chambers and have them share their port a little more. There will be serious cancellation in your current design. if you like a design like that try out this: http://www.decware.com/whorn.htm