advice/info greatly needed

[brandinooooo 10+ year member]

I'm trying to design a box for a Obsidian Audio 15. I would like to do a bandpass box instead of a normal ported box. I've been trying to find info on the difference and usefulness of the two. The most info I've found is here:

Bandpass..... explained.

How do I know which one (4th or 6th) would be better suited for my sub?

In the link above, it says to use this equation to figure out which order to use:

Fs/Qes = EBP

It says EBP under 70 - 4th order, and EBP above 70 - 6th order. Is this a reliable method? Or is there some other way? (OA 15 came out to 50.xx)

I've been running numbers through WINISD and this is what I've got so far:

full size 4thvs6th.png picture by scwolves10 - Photobucket

Also, how musical are these boxes? Is there a certain ratio for the chambers and tuning?

Any help is appreciated.

PS. Would be going in a Tahoe.

Click to read more...

 

[Electrodynamic 10+ year member]

It depends on how much room you have to work with and what your goals are. If you don't have a ton of room to work with go with the 4'th order. However, if you have a large amount of room to work with you can choose to use a 6'th order and have a larger bandwidth. Keep in mind that 4'th orders also peak lower in-vehicle than what they are designed at. For instance, a 4'th order tuned to 50 Hz can peak at 38 Hz when installed in a vehicle. Also toss what WinISD says about ported or non-ported based on EBP out the window.

 

[brandinooooo 10+ year member]

It wasn't WinISD that said that. It was an article that d2k found on here. No sure how reliable it is though.

Which would be more musical you think? Or does it depend on the tuning.

 

[Electrodynamic 10+ year member]

6'th orders can be more musical. But I think it's kind of funny when people ask about musicality in bandpass enclosures since BP enclosures purposefully shrink your bandwidth to gain output and a large bandwidth is what being musical and having great transient response is about. Having said that, the enclosure with the largest bandwidth will technically be more musical but not very many people are worried about the spectral decay of track 4 on the Stereophile Test CD 2 when they're designing bandpass enclosures. Bandpass enclosures are / can be very loud over a moderate frequency spectrum, which is exactly what they are intended to do. If it were me, I would personally go with a 4'th order unless you have a truck with a camper shell on the back and you don't care about taking up 8 to 10 ft^3 total for a single 15.