Cab for eminence B810 driver

[kringle77]

I have 4 b810 drivers. They require 0.9 sqft. for each driver. I have a cab, that if sealed, would supply about 1.2 sqft per driver. Is this close enough for a sealed cab or will it have undesirable effects? Thanks

[MuzikMan]

According to their website that driver's recommended sealed enclosure volume is 0.5 to 1.3 cu. ft.

Speaker Detail | Eminence Speaker

[billfitzmaurice]

Originally Posted by kringle77

I have 4 b810 drivers. They require 0.9 sqft. for each driver. I have a cab, that if sealed, would supply about 1.2 sqft per driver. Is this close enough for a sealed cab or will it have undesirable effects? Thanks

It will go lower, which is hardly undesirable. The 'ideal' volume for the B810 is actually 11 cu ft.

[kringle77]

Cubic feet, thats what I meant. Thanks guys, I may have to try it. Any suggestions on what the best way to seal up a vent slot is?

[will33]

Originally Posted by kringle77

Any suggestions on what the best way to seal up a vent slot is?

Cut a piece of wood to fit, or at least close and use a healthy dose of this glue.

Loctite 10 oz. PL Premium Polyurethane Construction Adhesive - 1390595 at The Home Depot

It expands as it cures to seal up any seams, crooked cuts, etc. It's stronger than the wood is after it's cured. Then hit it with a cheap can of flat black spray paint. Should probably add some polyfill stuffing to the cab or at least make sure it's lined good.

[kringle77]

I had these drivers in the bottom of my 8x10 and they sounded good but, maybe alittle too conjested sounding or boomy in the low mids. Would giving each driver 1.2 cuft instead of 0.9 cuft ease this issue?

[billfitzmaurice]

Originally Posted by kringle77

I had these drivers in the bottom of my 8x10 and they sounded good but, maybe alittle too conjested sounding or boomy in the low mids. Would giving each driver 1.2 cuft instead of 0.9 cuft ease this issue?

Booming is caused by too small a cab and insufficient cab damping. A larger cab and better damping would help.

[Petebass]

Sealed enclosures are a lot more forgiving to changes in cabinet volume than other enclosure types. Go for it.

[kringle77]

Thats good to know. There is plenty of dampening material in my ampeg cab so, these drivers may actually work pretty well in the other. I have to try it.

[kringle77]

I've got another cab that has 1.6 cuft per each (4) driver and three 4" diameter 4.5" long ports. Eminence has a large ported cab design for the b810 drivers that requires about 1.73 cuft per driver and four 4" ports, 2.75" long. I think that if I just plugged one of the current ports, I'd be fairly close to that tuning. It's not the same as the sealed design but, maybe I'll like it. I'll try that one first since it requires almost no work.

[beans-on-toast]

Originally Posted by kringle77

I had these drivers in the bottom of my 8x10 and they sounded good but, maybe alittle too conjested sounding or boomy in the low mids.

Maybe it would help with the boomy-ness to get the B810's off the ground. Try flipping your cabinet upside down. If it helps you can swap the upper and lower quartet.

It could also be that your stuffing is ineffective. Try a different material or more of what you already have.

[billfitzmaurice]

Originally Posted by beans-on-toast

Maybe it would help with the boomy-ness to get the B810's off the ground. Try flipping your cabinet upside down. If it helps you can swap the upper and lower quartet.

It could also be that your stuffing is ineffective. Try a different material or more of what you already have.

That won't make much, if any, difference. Only if there's open space between the radiating plane (baffle) and floor is acoustic coupling disrupted.
But with roughly 1 cu ft per driver the system Q is about 1.1, and that very much causes boom. Stuffing the cab with polyfill will reduce Q, and boom along with it. That's why I said the ideal cab size is 11 cu ft, as that's how large it must be for a boom-free Q of 0.7.

[kringle77]

Im guessing that the answer will be no but, if I was to put extra stuffing into a sealed cab that was alittle too large, would that help?

[billfitzmaurice]

Originally Posted by kringle77

Im guessing that the answer will be no but, if I was to put extra stuffing into a sealed cab that was alittle too large, would that help?

No, because stuffing lowers Q, and a cab that's too large has Q that's too low. It's hard to imagine a cab that's too large, though.

[kringle77]

Thanks Bill, thats what I thought. I was checking the measurements again and the suggested sealed cab design with four b810 drivers was around 3.8 cuft. The cab I want to seal actually has 5.6 cuft. Big difference. Im thinking that, as you say, this would give me a much lower tuning frequency. Maybe not desirable sound wise. I'll try it though.

[billfitzmaurice]

Originally Posted by kringle77

Thanks Bill, thats what I thought. I was checking the measurements again and the suggested sealed cab design with four b810 drivers was around 3.8 cuft. The cab I want to seal actually has 5.6 cuft. Big difference. Im thinking that, as you say, this would give me a much lower tuning frequency. Maybe not desirable sound wise. I'll try it though.

Like I said, the B810 driver has a Q of .7 in an 11 cubic foot cab. For a 4x that's 44 cubic feet. Anything smaller than that will have a higher Q. The suggested cab size by Eminence isn't for maximally flat response, as they recognize that it's not a realistic goal anyway.

[Arjank]

You could try CHP, which means Closed High Pass.
In short it's this concept: put a driver into a to small closed cabinet (Q around 1), add a large capacitor in series with that driver. The capacitor will interact with the impedance curve of that driver. When everything "fits" the capacitor will lower the mid-bass bump, add up to 3dB just beneath the Fb of the cabinet and below a certain point it will also act as a subsonic filter.
If you want I can simulate it for you and see if the driver is suitable for this concept.

[3rdcurve]

Originally Posted by kringle77

I had these drivers in the bottom of my 8x10 and they sounded good but, maybe alittle too conjested sounding or boomy in the low mids. Would giving each driver 1.2 cuft instead of 0.9 cuft ease this issue?

This is the first post I have found of someone not liking the b810s in a ampeg cab. Do you not prefer them to the stock or mod speakers? I have a pretty expensive build focused on these speakers in progress, and would hate to be disappointed with the tone.

[kringle77]

No, they sound good. Actually, my favorite combo is 4 of them in the bottom of an 8x10 with 4 mods in the top. 6 and 2 would probably be really good too. Probably better. Thats actually my favorite sounding cab. The 2-way fearful that Im borowing from LOMO is clearer, lighter and more efficient though. Just a different character. Clean vs gritty. Thanks guys. Im thinking that if someone was to put 4 of these in a cab with 2 mods, they'd have something as good as a berg nv610. It would be brighter than the berg. I've always wished the berg was 20" wide so that the center of the drivers are close and offset by 5". You could then put at tweet in the upper corner for when you want alittle modern sparkle.

[3rdcurve]

Good to hear, I am actually looking for the gritty tone.