Building a 4x12 bass cab

[Floyd Eye]

So someone is giving me an unloaded Peavey 4x12 cab from the 80s. He says it was used for bass. It's taller and wider than a standard 4x12 guitar cab and it is slot ported. I know you are supposed to design a cab around the speakers and not the other way around, but in this situation, what would be the best course of action regarding picking the speakers for this cab? I do not have the cab in my possession yet by the way.

[Phendyr_Loon]

Originally Posted by Floyd Eye

So someone is giving me an unloaded Peavey 4x12 cab from the 80s. He says it was used for bass. It's taller and wider than a standard 4x12 guitar cab and it is slot ported. I know you are supposed to design a cab around the speakers and not the other way around, but in this situation, what would be the best course of action regarding picking the speakers for this cab? I do not have the cab in my possession yet by the way.

Model a few different drivers in WinISD, the best case is that you may end up just having to modify the port dimensions.
There are heavier, less expensive options for 12" drivers but check out the Basslite S2012. The Basslite line does small enclosures better than most.

[Floyd Eye]

Thanks for the reply. Those speakers look pretty nice. Affordable too.

[kraigo]

Definitely model it in something like WinISD. The S2012 is a very cool speaker, but it might not work well in that cabinet. At the very least, do your best measurements (internal height, width and depth, internal port dimensions) and post what you find. Pictures would help as well. Perhaps someone will be kind enough to mock it up in WinISD and make a driver recommendation as well as recommending any modifications.

It will also help to know whether your needs lean toward efficiency or low frequency handling. You will only get one at the expense of the other. Do you play a low B or lower?

Of course, I just noticed the "extended range bass club" in your sig. Do you have oodles of power?

[Floyd Eye]

I do have a 6 string, but these days I am primarily gigging with my 4001. My amp is rated at 1000 watts @ 4 ohms. I should have the cab in my hands this afternoon and will post pictures and dimensions as soon as I can.

[solodb]

A friend gave me one of those Peavey slot ported cabs awhile back, too. I really like it a lot. It's the one where the two compartments are completely seperated , right ? I didn't have any cash for proper bass speakers so I ended up loading it with 4 old school Akai drivers each 8 ohms and 60 watts. I totally lined all the walls with 1" enclosure insulation. Wow, it's got good bass throw and sounds very clean as well! My amps are only 100 watts , so the janky speakers I threw in are ok for now. It seems to be efficient , but I have some random rattles to track down. I will be following this thread to see how you make out.

[Sunnmon]

Hello Floyd Eye,
I personally like 12" speakers for bass. They are this century's 10" speakers

The Aguilar GS412 and the SWR 412 Stack use this speaker.
The current part number for those speakers is 0067085000. They are made by Eminence. I hope this will help you out.
Naysayers will all say you cannot use a speaker that isn't designed for the cabinet blah blah blah cuz of my Win-Dixie Program tube port-caster size-grill cloth color compatability and such but if yer gonna use that PV cab these will roar.
Fact.

and now go ahead and flame me and tell me to get a fEARfUL or some boutique cabinet, OP wants to use it, Speakers are around $75 a wack.

Happy Holiday and Peace and Happiness to all

[DaZombieWoof]

Well, a speaker will behave as well as it can in a cab that is properly tuned. Sometimes a speaker misbehaving is the grail tone for somebody. Most all musical instrument speakers from a hifi perspective are crap. Distortion monsters and profound non-linearities. That describes a Celestion loaded Marshall cab in all fairness. A double stack of the lower resonance Celestions they loaded their bass cabs with kicked by an SVT was cool barking monster back in the day that I lusted after, providing I could get a road crew to move it for me.

[will33]

Originally Posted by Sunnmon

Hello Floyd Eye,
I personally like 12" speakers for bass. They are this century's 10" speakers

The Aguilar GS412 and the SWR 412 Stack use this speaker.
The current part number for those speakers is 0067085000. They are made by Eminence. I hope this will help you out.
Naysayers will all say you cannot use a speaker that isn't designed for the cabinet blah blah blah cuz of my Win-Dixie Program tube port-caster size-grill cloth color compatability and such but if yer gonna use that PV cab these will roar.
Fact.

and now go ahead and flame me and tell me to get a fEARfUL or some boutique cabinet, OP wants to use it, Speakers are around $75 a wack.

Happy Holiday and Peace and Happiness to all

Any driver will make sound in any box. I'd assume if somebody was dropping money on speakers, they'd want as good a result as they can afford?

You do have a point to some degree though. In the case of 410's, I've pretty much quit telling people to reverse engineer everything in that particular case. Most commercial 410's are all real close in size and none were designed with premium sound as top priority. Those you pretty much can just stick various differently voiced drivers in and see how they sound, maybe make slight tuning adjustments.

As far as liking "12's for bass", size means nothing. In the OP's case, measurements are needed. Many older cabinets were tuned too high for the newer drivers.

[Floyd Eye]

This is the cabinet. The 2 sections are separated. The inside depth is 11 5/8", width is 26 1/2" and each section is 16" to the baffle with a 2 1/2" port on the bottom of one and the top of the other.

[MuzikMan]

Definitely get rid of the fiberglass and replace it with something like mattress topper (unless you would like an itchy bomb)

[VanillaThundah]

Originally Posted by MuzikMan

Definitely get rid of the fiberglass and replace it with something like mattress topper (unless you would like an itchy bomb)

+ 1

You will be digging that crap outta your arms for WEEKS if you leave it in there while installing your speakers lol

[Floyd Eye]

I am a carpenter/residential remodeling contractor. Fiberglass insulation is nothing new to me. Nevertheless, I will be removing it and using the egg crate shaped foam insulation instead.

All I need is the speakers and whatever components and wiring information I need to make the cabinet 4 ohms. My amp is rated at 1000 watts, so I would guess the speakers need to be 250 watts each?

[Mr. Foxen]

Looks to be chipboard. Not ideal to be spending much time/effort on redoing. If you put in nice speakers, be prepared to pull the speakers and bin the box when its time to move it on, or make a new ply box for those speakers.

[will33]

So each section is 16" high and then the port is 2-1/2" high or deep? It also looks like the port doesn't go all the way to the side walls.

Basically have to calculate the internal volume of the chambers, then subtract the external volume of the port that sticks inside the box from that to find the net internal volume of the chambers, then measure the internal height, width and depth of the port to find the box tuning.

[will33]

Originally Posted by Floyd Eye

I am a carpenter/residential remodeling contractor. Fiberglass insulation is nothing new to me. Nevertheless, I will be removing it and using the egg crate shaped foam insulation instead.

All I need is the speakers and whatever components and wiring information I need to make the cabinet 4 ohms. My amp is rated at 1000 watts, so I would guess the speakers need to be 250 watts each?

Then you need 4ohm or 16ohm drivers. That's some pretty heavy material and most of the dimensions aren't long enough to need a lot of extra bracing but I'd run one stick from between the driver cutouts to the back wall and maybe one vertical stick in the middle of each chamber, that's about it.

[billfitzmaurice]

Originally Posted by Floyd Eye

My amp is rated at 1000 watts, so I would guess the speakers need to be 250 watts each?

The driver power rating is moot. How much power they can actually make use of is determined by their displacement and the cabinet. This is one of the factors that WinISD Alpha Pro can calculate. Having to use 4 or 16 ohm drivers makes your choices very limited.

[will33]

Originally Posted by billfitzmaurice

The driver power rating is moot. How much power they can actually make use of is determined by their displacement and the cabinet. This is one of the factors that WinISD Alpha Pro can calculate. Having to use 4 or 16 ohm drivers makes your choices very limited.

It does indeed.

OP, I assume your amp is 600 or so watts @ 8ohms. There's really no downside to making it an 8ohm cab if you're thinking power/output. The upside is it opens you up to a lot more choices of better drivers.

[Floyd Eye]

Originally Posted by will33

So each section is 16" high and then the port is 2-1/2" high or deep? It also looks like the port doesn't go all the way to the side walls.

Basically have to calculate the internal volume of the chambers, then subtract the external volume of the port that sticks inside the box from that to find the net internal volume of the chambers, then measure the internal height, width and depth of the port to find the box tuning.

That is very confusing. The ports are 2 1/2 inches tall. There is a piece of wood ( like a shelf) at 16" which goes all the way to the sides but comes 2 1/2 inches away from the back of the cab. Then there is 2 1/2 inches below that ( port). The port goes all the way to the side walls on the inside.

I guess I am not opposed to an 8 ohm cabinet.

[will33]

I'm getting right at 3 cu.ft. per chamber so 1.5 cu.ft. per driver. If I could run WinISD on this phone I wouldn't need a PC but alas, can't predict the tuning, although the shelf is already as deep as you can make it. Might be low enough. Raising the tuning would mean cutting back a portion out of the shelf, lowering tuning would mean blocking off part of the opening.