Building 4 Dual 18 boxes, help needed and build thread

[killersoundz]

Hey guys you know when I get on here and chat sometimes I like to pretend that I know everything but when it comes down to business and entering a new area I start having questions. ;) I just got a client from a local venue that wants me to build him 4 Dual 18 boxes. :D He was originally talking to me about buying speakers from me to upgrade the ones in his current subs, but I successfully explained to him that's more or less going to be a waste of money since the boxes are more of the problem than anything. They're EV kickbins and Nady dual 15's :rolleyes: The harmonic distortion from those subs when they're crankin' I believe exceeds the fundamental notes at times when I've heard them, I'm not even joking.

We're going with 8 Eminence Definimax's. I'm already imagining these in the smallish room, it's going to be a major upgrade for them especially on dance tracks. He has to currently HP those subs pretty high so some of the fundamental subbass is non-existant in some of the dance music they play.

Anyways the most obvious format to build these in is 2x18 boxes. I'm deciding whether to slot port the boxes on either end or just one giant rectangle port in the middle. Obviously bracing the back becomes and issue with the single giant rectangle port in the middle, it would have to be built into the port somehow. Which would you go with?

[AMC]

Re: Building 4 Dual 18 boxes, help needed and build thread

Hey guys you know when I get on here and chat sometimes I like to pretend that I know everything...

Isn't that what the internet is for? I have never used the definimax, but it sure looks like a good driver.

Just purely for aesthetics, I would use a slot port at each end. But that is very subjective. I have seen some cabs that use 2 triangular ports between the two woofs, seems a good ways to port it without making the cab any larger.

Just to save BFM the time, why not a folded horn?

[billfitzmaurice]

Re: Building 4 Dual 18 boxes, help needed and build thread

Just to save BFM the time, why not a folded horn?

Probably because the client thinks there's something special about using eighteens. I know better, so I don't. ;)

[wg_ski]

Re: Building 4 Dual 18 boxes, help needed and build thread

why not a folded horn?

Harder to build? Already has the drivers? The Definimax reportedly won't work well in a horn due to cone flex.

But four 2x18's is definitely getting up to the 'critical mass' needed to get horns flat to 40.

[billfitzmaurice]

Re: Building 4 Dual 18 boxes, help needed and build thread

Harder to build? Already has the drivers?

Doesn't know any better. Not that 2x18s can't work well, but dollar for dollar and pound for pound horns crush them. They only have the advantage of smaller size, an advantage wiped out by the much higher power requirement.

The main reason 2x18s remain popular is price, you can get them for under a grand, so they're ubiquitous. Commercial horns like Danley aren't widely seen because so few can afford them.

[killersoundz]

Re: Building 4 Dual 18 boxes, help needed and build thread

Brotha, I know folded horns are the way to go, the low harmonic distortion sounds so clean from them. You're gonna laugh but I really don't have the time or the budget to pay myself for labor to construct them in this deal. Either way this club is pretty small, I'd say the room is 1500 sq ft. 8 relatively low distortion 18's will get it pounding pretty hard. The other problem is that the ceiling in this place is real low, i'd say its like 9ft so the stage is only about 6 inches off the floor and the subs need to remain pretty low profile.

Anyways I'm sure we're going to be satisfied with the results, it's going to be an upgrade from the EV kickbins and nady dual 15's for sure.

[Paul O]

Re: Building 4 Dual 18 boxes, help needed and build thread

But four 2x18's is definitely getting up to the 'critical mass' needed to get horns flat to 40.

Yep.. four 15" loaded horns would create the same if not more output with a fraction of the input power, but of course the boxes are more complex to build and these would need to be co-located(clustered) to deliver that performance. And the customer may have an adversion to horns now despite the fact they have been using an old bass bin as a sub.. which we know isn't the same thing but you probably won't convince the customer of that.

If you do build the dual 18s I like the look of a single central port though I'd actually design the boxes as mirror imaged seperates with the ports together in the middle, that way each driver is loaded seperately and can function independantly should the other die for whatever reason.

[killersoundz]

Re: Building 4 Dual 18 boxes, help needed and build thread

Yep.. four 15" loaded horns would create the same if not more output with a fraction of the input power, but of course the boxes are more complex to build and these would need to be co-located(clustered) to deliver that performance. And the customer may have an adversion to horns now despite the fact they have been using an old bass bin as a sub.. which we know isn't the same thing but you probably won't convince the customer of that.

If you do build the dual 18s I like the look of a single central port though I'd actually design the boxes as mirror imaged seperates with the ports together in the middle, that way each driver is loaded seperately and can function independantly should the other die for whatever reason.

You brought up a good point, in this room we can't have a single cluster, they HAVE to be on either side of the stage. It's a major drawback. Also good idea about having the subs loaded separately I'll try to work that into the design. Like I said unfortunately I am working on a relatively tight budget on this deal in terms of labor cost. The budget is also restricting me from using my typical ridiculous A+++++ quality baltic birch plywood so I'm going to have to incorporate some cheaper alternatives into these. Good thing they are more or less a permanent install.

[killersoundz]

Re: Building 4 Dual 18 boxes, help needed and build thread

Here's some pics of the venue. There's also a couple other things that could be better about their setup, like it would be more ideal for the stage to be at the long end of the room, but that's something that can't be changed.

[killersoundz]

Re: Building 4 Dual 18 boxes, help needed and build thread

Just To Save Bfm The Time, Why Not A Folded Horn?

Lol

[wg_ski]

Re: Building 4 Dual 18 boxes, help needed and build thread

The budget is also restricting me from using my typical ridiculous A+++++ quality baltic birch plywood so I'm going to have to incorporate some cheaper alternatives into these.

Look into using Araucoply - $40 a sheet. I used it to build the cabinets (not speaker) in my new shop and it was a PLEASURE to work with compared to low cost 'birch'. 5 solid plies (no veneer to peel off) and almost no voids at all. Good on both sides. I'll be using it for my next speaker builds.

[killersoundz]

Re: Building 4 Dual 18 boxes, help needed and build thread

Look into using Araucoply - $40 a sheet. I used it to build the cabinets (not speaker) in my new shop and it was a PLEASURE to work with compared to low cost 'birch'. 5 solid plies (no veneer to peel off) and almost no voids at all. Good on both sides. I'll be using it for my next speaker builds.

I've seen that stuff at menards and I was relatively impressed with the way it looked from the outside. It did look like it would be better to work with than the cheap chinese birch which is something I'd like to avoid all together. I'll probably end up going with the araucoply and some MDF for bracing or the backs possibly.

Did you do a round over on the araucoply? If so did it tear out at all? that's my biggest concern since I'm probably going to paint these boxes black I don't have to have to do a ton of 'body work'. Forgettabout it with that cheap chinese birch plywood, that stuff is a joke.

[wg_ski]

Re: Building 4 Dual 18 boxes, help needed and build thread

Roundovers work much better on Araucoply than on cheap chinese birch. I went through SO MUCH BONDO it wasn't funny to fix tear outs on some chinese birch cabs I built. Funny thing is some of that cheap chinese stuff was actually decent and I had no trouble at all. But that batch is long gone.

[killersoundz]

Re: Building 4 Dual 18 boxes, help needed and build thread

Roundovers work much better on Araucoply than on cheap chinese birch. I went through SO MUCH BONDO it wasn't funny to fix tear outs on some chinese birch cabs I built. Funny thing is some of that cheap chinese stuff was actually decent and I had no trouble at all. But that batch is long gone.

Great! That's definitely what I'll be using. If I tried to use the $80/sheet plywood I normally get I would probably be in the hole on this deal. 4 dual 18's = lot of material. These boxes are going to be 48" wide x 22" tall by 30" deep or so

[AMC]

Re: Building 4 Dual 18 boxes, help needed and build thread

If it's 'permanent' I would use as much MDF as I can. And Yes, 8 of those drivers are going to make some serious SPL.

Nice place.