Behringer B1800d Enclosure rebuid

Hey fellow DIY'ers. I couldn't find any forums related to the question i have so i figured i would start a new one.

A while back i got 4 behringer b1800d subs. They have served me well over the last year or so, but as is to be expected from a sub like this, the mdf cabinets have begun to fall apart. With damage varying from torn exterior finishing to one of the cabinets nearly splitting in half, i figured its time to build new cabinets for them. They are not in any condition i would be willing to sell them in so selling them and starting from scratch isnt much of an option.

And being a bit of a noob in the art of cabinet design , i have a few resulting questions.

1: what cabinet material should i use? I figured Baltic birch would not be worth using with such cheap hardware and mdf will suffer the same problems that the original cabinet had. Would some 5/8" or 1" birch ply work.

2: Cabinet style. Should i stick with a bass reflex cabinet or should i try something a little more exciting like a bandpass or hybrid horn. I have to guess the driver will have Ts parameters suited more to bass reflex but would i gain any benefit from another enclosure type. I would be willing to put the extra effort in to a more complex enclosure if it was to provide any benefit.

3:If i were to stick with Bass reflex would round or slotted port be more beneficial.



Ill try to answer questions regarding missing information wherever i can.

Thanks for any advice i may receive in advance!
 
I'd use whatever cheap 3/4" birch or poplar ply you can get at Home Depot or Lowes. Should be around $45/sheet. It's not premium wood like real baltic birch, but for all but the most extreme applications it will hold up just fine. When braced reasonably it will make extremely solid cabinets. Personally I'm of the opinion that MDF is garbage for PA use, and for Behringer subs like that spending the money for BB is a waste. Round the edges with a router, buy some corner protectors and rubber feet, and paint the cabinet with Duratex.

I'd honestly just copy the same enclosure properties. If it was a strong driver you'd have options, but it's not. Do ported with the same internal volume and port size. I'm sure you COULD design a different cabinet, but I don't think it's worth it.

For the most part a port is a port as long as it's the same size and tuning. That said there are a few nuances like slot ports tend to be nice in that they reinforce the cabinet and often will often have a lower tuning for the same length due to the internal walls changing the end flow behavior. Tube ports, especially if flared properly, can produce the lowest port compression and least turbulence.

I'm kindof a fan of this port design.
[IMGDEAD]http://h-audio.de/shop/catalog/images/RCF_LF18N401_Sub.jpg[/IMGDEAD]
It allows for minimal frontal area, stiff cabinets, and like a slot port the walls tend to lower the tuning a bit for the same length. But really it doesn't matter a whole lot as long as the tuning is right and it's big enough to not be chuffing badly at full power.

You could also consolidate cabinets in to two double 18 cabinets. Obviously that reduces your flexibility, but you can save some weight and some wood by eliminating the two panels they join at.
 
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WOW. Thanks for pretty much answering all of my questions in one shot! Ill try to Shimmy together an enclosure design over the next couple days and ill post it here for scrutiny.

If anyone would like to draw up a quick enclosure feel free to do so ;)

The enclosure volume looks to be about 130L if i calculated correctly. Ideally I would like to re build the B1800d into a unit with a more square front and more depth. Something with a similar shape to the EV ETX-18SP for storage reasons.
 
Hey GM. The driver in the b1800d is oem. Ive tried looking for ts parameters but have come up empty handed. All i know currently about the driver is that it is 6 ohms with a 500Wrms 1000Wprog 2000Wpeak power rating. Im tempted to see if i can get the proper specs from music group. Ill try in a couple days.
 
Hey GM. The driver in the b1800d is oem. Ive tried looking for ts parameters but have come up empty handed. All i know currently about the driver is that it is 6 ohms with a 500Wrms 1000Wprog 2000Wpeak power rating. Im tempted to see if i can get the proper specs from music group. Ill try in a couple days.

Find someone with a DATS. Or just measure them manually yourself. A google search should turn up a few techniques to do this.
 
Ill see what i can find in terms of testing the driver. If i can do it without spending alot of $$ ill probably do so. May as well try to make the most of the parts ive got. Though i think im just going to end up selling these as soon as the cabs are built and make between 4 and 8 th-18's with B&C 18sw115-4's. They just seem too tempting not to build ;)
 
perfect. Ill have to take a look at that. So far just playing around with something similar to the original box, i have come up with an slot ported enclosure measuring (WxHxD) 23.5"x 21.5"x 25" (outside measurements) out of 3/4 birch. The original behringer enclosure has dual 6" diameter ports with a length of 9.75" on both. If i calculated correctly the tuning is around 40.5hz. To me this seems a bit high. Is this normal for a pa cab? I was thinking about tuning the new cab to around 32-35hz. Would you say this is not recommended. Thanks.