compact 2x15 cab build

[The Fury]

Does this sound like a good idea? I've got some speakers laying around I bought for some PA cabs a while back and I need a cab so I figure why not? I want it to be portable so the idea is to build the most compact 2x15 I can. I'm not expecting it to have a ton of low end like a normal 2x15 but do expect good punch (think lower mids).

 

So, any suggestions, ideas, opinion?

[bassesofalessergod]

dual side firing!

[The Fury]

Well I guess nobody thinks much of my idea

 

meh I'll try the EG forum

[bikehorn]

The ideal size of your cabinet is going to depend on the specifications of the drivers. If you want a relatively small cabinet and you still want to retain low end response you need speakers with the smallest Vas(compliance volume) possible and with ported boxes a lower Qts tends to work better.

 

If you don't have the specifications for the speakers you have on hand, you can build a box and see what happens. Internal volume is usually proportional to low end extension.

[The Fury]

here are the speakers

 

I cant find the detailed specs, not yet at least

[bikehorn]

Those have really low sensitivity for instrument use. You are going to have to dump a lot of power into them to get volume. Paralleling two of them would give you 4 ohms, resulting in a perceived 3dB boost in volume over a single 8 ohm 15" driver.

 

If you've got the amplifier muscle to drive them, I say go for it.

[The Fury]

Those have really low sensitivity for instrument use. You are going to have to dump a lot of power into them to get volume. Paralleling two of them would give you 4 ohms, resulting in a perceived 3dB boost in volume over a single 8 ohm 15" driver. If you've got the amplifier muscle to drive them, I say go for it.

 

my amp puts out 300 watts at 4 ohms

 

I was gonna wire it to 4 ohms though.

 

should I go sealed or ported?

 

I though about mixing it, the bottom speaker ported, and the top speaker closed off in its own internal cab. Not sure though.

 

And should I use .75" plywood? I figured thats the norm, but I dont know.

[The Fury]

I know its late now, but thanks for all the help guys

 

55 views, 7 posts, 4 of which are mine

 

thanks bikehorn for your advice

[Emprov]

 

And should I use .75" plywood? I figured thats the norm, but I dont know.

 

.75 ply should work out ok, a lot of builders like to go with a 1" baffle, not sure how much of an overall difference that'd make though. Wait until the morning, perhaps some of the guys in the know will show up with some dimension options.

[burdizzos]

3/4" is fine, I can't seem to fine enough data on the speaker to get what I want.

 

Parts Express recommends a 3.5 cubic foot sealed box.

 

PDF link

[Mudbass]

Sensitivity (1W @ 1M) 90.2db.

 

I hope you have an enormous power amp cause you're gonna need it.

[t3ch]

I know its late now, but thanks for all the help guys 55 views, 7 posts, 4 of which are mine thanks bikehorn for your advice

 

Because everyone on a FREE bass forum on a FRIDAY NIGHT (where many people gig, not to mention) are at home on the forums

 

 

[isaac42]

More complete specs are here: http://www.pyleaudio.com/manuals/PPA8-10-12-15-18.pdf

 

This isn't well suited for a small cabinet.

Fs 26.7

Qts 0.67

Vas 11.357

Not much, but enough to work with.

 

It has an efficiency bandwidth product (EBP) of 30.0, meaning that it's better suited to a sealed cabinet than a ported one.

 

Even in a 12 ft^3 cabinet, you get a 2dB peak at about 60Hz. In a compact cabinet, say 32"x24"x18", the Qcb goes up to 1.31 and the peak increases to 3dB.

 

Any Qcb above 1.0 isn't going to be hi-fi, but this isn't hi-fi, is it? In a small cabinet, these drivers are going to have a fairly large peak in their response, but it's a fairly wide and flat peak, so it shouldn't be ringy, one-note bass. It should thump to beat hell. It's not terribly sensitive, but the 2-3dB peak will help a bit with that. Still, you're not going to fill a large room at rock levels unless you get more power than 300 watts. No figure is given for Xmax, so there's no way to tell what the max output is. I wouldn't recommend a ported cabinet. All it would do is make the peaking worse.

 

I'd go with a sealed cabinet, as large as you're comfortable with, then stuff it with lots of stuffing. Fiberglass is probably best, but some people don't like working with it. Your choice.

 

An alternative would be an open back cabinet. With a Qts of 0.67, it will be pretty much flat down to the rolloff frequency determined by the baffle width. Put a cabinet on either side of it, and it would go pretty low.

[The Fury]

Sorry for the friday night rant, thanks a ton for the help

 

Seeing as how this are not very efficent speakers and my amp only pumps out 300 watts, perhaps I should look into buying a couple of new speakers?

 

Idealy I'd want a 1x12 or a small 2x10, maybe a small 1x15

 

The 2x15 I think is a bad idea now. It just seems a little silly to try to cram 2x15's into a small cab.

 

After I buy speakers, wood, hardware this could be expensive.

Perhaps I should just get an Avatar cab

[bikehorn]

Eminence Gamma 15s are a nice speakers. They aren't too expensive, they've got a sensitivity of 99 dB, 300 watt RMS power handling and their Qts of 0.3 makes them a good candidates for ported boxes. With two of them you would have a 4 ohm, 600 watt RMS ported cabinet.

[burdizzos]

In most cases, it's cheaper to buy than to build.

 

If you enjoy building, then go for it. I've built several boxes that I enjoy.

 

In fact, I just finished up a 6th order bandpass PA sub using an 18" driver.

 

 

I will say that if you're going to build, don't have ass it on components. If you're going to invest the time and money into a speaker building project, then buy good speakers.

[The Fury]

 

In most cases, it's cheaper to buy than to build. If you enjoy building, then go for it. I've built several boxes that I enjoy. In fact, I just finished up a 6th order bandpass PA sub using an 18" driver. I will say that if you're going to build, don't have ass it on components. If you're going to invest the time and money into a speaker building project, then buy good speakers.

 

 

I think I'ma check out speaker prices and such. Then go up to the big local shop round here and check some prices on handles and corners (they sell that stuff, along with just about everything you can imagine, way better than GC).

 

if the $$ adds up too high than I'll prolly look at avatar or maybe that 1x12 aguilar cab.

[Crescent Seven]

 

I will say that if you're going to build, don't have ass it on components. If you're going to invest the time and money into a speaker building project, then buy good speakers.

 

 

+1. Everything revolves around the driver with respect to the design of the cab, so if you decide the cab sucks, it's not as simple as swapping in a new driver.

 

Building a cab is a lot of work, make sure that it's going to be worth the time and money when it's finished. You're going to be surprised what the total is once you factor in the cost of corners, grille, feet, tolex, jack and plate, screws, glues, sawblade if you need one, etc. So using a driver that's just laying around is not likely to give you a result that's worth all that effort.

 

That said, cab building is fun, if you're interested in it you should buy the nicest driver you can afford and work from there.

C7

[The Fury]

 

+1. Everything revolves around the driver with respect to the design of the cab, so if you decide the cab sucks, it's not as simple as swapping in a new driver. Building a cab is a lot of work, make sure that it's going to be worth the time and money when it's finished. You're going to be surprised what the total is once you factor in the cost of corners, grille, feet, tolex, jack and plate, screws, glues, sawblade if you need one, etc. So using a driver that's just laying around is not likely to give you a result that's worth all that effort. That said, cab building is fun, if you're interested in it you should buy the nicest driver you can afford and work from there. C7

 

 

yeah I agree

 

I think I'ma wait on the build and just go for a 1x12

 

thanks though, I'll revive this thread if/when I get the stuff together to do a build though

[bassman1956]

 

In most cases, it's cheaper to buy than to build. If you enjoy building, then go for it. ........... I will say that if you're going to build, don't have ass it on components. If you're going to invest the time and money into a speaker building project, then buy good speakers.

 

 

 

Jake, true words, very true words!

 

 

The more I build stuff, anything at all, the more I'm convinced, regardless of what it is, or if it's your first or fifty first, this is truth!

 

Sometimes what you want is simple, and you talk yourself into something complex. Complexity is not a substitute for quality. Stay simple if that's what you want, just don't buy junk.

[Crescent Seven]

 

yeah I agree I think I'ma wait on the build and just go for a 1x12 thanks though, I'll revive this thread if/when I get the stuff together to do a build though

 

 

With the 12's that are out there these days, you can do some really neat things with a 1x12 build. The 12" Deltalite II is awesome for a lightweight build, and IMO they work very well using midrange drivers. If you were to build a slightly larger than normal 1x12, you'd have a cab that could get as loud as any 1x15, and in alot of cases, just as low.

C7