Im looking for some quick/basic subwoofer box design guidelines/ideas.

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I have 2 (a pair) of these,

Tang Band W6-1139SI 6-1/2" Subwoofer 264-832

id like the smallest box (portable boombox) with deepest and loudest output *optimal* no higher then 41hz.

i tried this and dont really like it because i can bottom the drivers out quite easily

Cerberus

im happy to try sealed/ported bandpass/hybrid... anything

i thought maybe some of you might have an interesting/fun idea ??
 
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Hi,

What sub amplifier are you using ? Does it have a low pass filter ?
If its doesn't that may be your problem. does it have a manual ?

Many commercial HT subs include built in limiting to prevent overload,
unfortunately this is very difficult to provide in a general purpose amplifier.

rgds, sreten.

There is nothing much wrong with the vented box design used.
 
Have you included a high pass filter set to just below port tuning?
This would stop over-excursion as the driver unloads, giving you much more mechanical power handling.

They're currently in a box about as small as it can be to get to 41Hz, unless you wanted to go isobaric (a waste for these drivers - the cabinet is already tiny).

Remember Hoffman's law: Small size, bass extension, efficiency. Pick any two.

Expanding a little: you can never get loud, low bass out of something portable. Ever.

Here's the options:
- get some high efficiency drivers, put them in a small box and make sure it peaks around 80-120Hz. This'll give the impression of having lots of bass, while keeping efficiency (therefore battery life) up.
- use your current drivers in their current alignment, power them with something modest (battery life...), and enjoy the fact that it'll go far, far lower than anything else similar. Won't be that loud, unless you fancy changing batteries every few minutes.
- build something big that's efficient and goes low, but be prepared to add wheels.

Chris
 
although im reasonably sure removing the port/s and
making the box a little smaller would also solve my issues?

sealed subs are good right ?

Hi,

Not really but here is something you could try :
Find some porous foam 6mm to 8mm thick, cut to 3 x port
diameter x port length, fold and insert into the port. This will
drop the frequency the driver unloads a lot and can work.

rgds, sreten.
 
Probably you are just getting what you can out of those 6.5s. Going sealed wouldn't help unless your ports are tuned higher than you think (check by sweeping/stepping a since wave) or you're playing rare music with a lot of sub-bass.

I'd recommend some kind of a folded (Bill Fitzmaurice) or tapped (Tom Danley) horn.

Can you specify more what you mean by "Boom Box"? 2 Cerberus is not that tiny, unless you mean a hoist-onto-your-shoulder "Ghetto Blaster" :p
 
I have 2 (a pair) of these,

Tang Band W6-1139SI 6-1/2" Subwoofer 264-832

id like the smallest box (portable boombox) with deepest and loudest output *optimal* no higher then 41hz.

i tried this and dont really like it because i can bottom the drivers out quite easily

A 4th order bandpass alignment might address that. I ran into the same problem with a cheap 10" driver I purchased years ago. It would bottom badly in a vented alignment. The sealed chamber of a 4th order BP alignment designed for a few dBs of gain fixed that problem. I did have to give up a little low frequency extension however.
 
Hi 60ndown,

Maybe one of bjorno's T-TQWTs would fit the bill? V_net=13.8 L.

Regards,
 

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Hi Brian,

He'll have to take care of the low-end excursion with a filter anyway. For the BP4 the duct seems to get very long. Volvotreter's small TH may be another solution, it's not tiny, but would still qualify as portable (if one builds it with 1/2" plywood), at least it has a little more output.

Regards,
 
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