S-Frame subwoofer?

[chris661]

I've had this idea (might even try it), where you (effectively) fold a baffle around a speaker, in the shape of an S

You'd put the woofer in the middle horizontal, and get a dipole output, but the baffle width would seem a lot higher (to the driver) which would result in increased bass output (there would be a lid on this design). I figure that, using an 8" woofer I have knocking around, I could make one that's 6" tall, and 9" square. These could be stackable, for increased bass output.

Someone may have already done this, but I thought it may be worth sharing as the search returned nothing.

Thanks for reading
Chris

 

[j.michael droke]

Hi There: An enclosure of this type is patetened by Axel Ridthahler and information can be found by Googling: RIPOLE R30. I have constructed a DIY 12-inch single enclosure (operating) and a verticle stacked dual 12-inch DIY version is nearing completion. The single driver version needs a driver with considerable Xmax, so I will be connecting the 2 drivers in the dual version in series. Also you can read-up on ripole, in open back threads and OB theory on Siegfried Linkwitz's site.
... Michael Droke

 

[chris661]

Ok, thanks for that. Time to do some more reading.

 

[Dr_EM]

...The single driver version needs a driver with considerable Xmax...

Yes, when I was experimenting with OB, I found the dual driver W-baffle/Ripole to have far more output. Worth persuing imo

 

[chris661]

Thanks for the encouragement. I thought they'd be a good way of getting reasonable bass from a small package - for an 8" woofer, you'd need maybe a 10" square, and 5" deep?

Seems like a good way to reduce size to me...

 

[j.michael droke]

Thanks for the encouragement. I thought they'd be a good way of getting reasonable bass from a small package - for an 8" woofer, you'd need maybe a 10" square, and 5" deep?

Seems like a good way to reduce size to me...

Hi there: My Ripoles use 12-inch driver(s) in 14x14-inch (14x28 for the dual) x 5.375-inch deep enclosures. ...regards, Michael

 

[tinitus]

Anyone tried a ripole this way ?

 

[chris661]

Looks similar to a W-frame system, but with a lid, and more edges. If you put the drivers at an angle to each other, you'll see what I mean.

Here's an idea. Make a ripole sub, but then stuff (heavily) one side. Maybe the attenuation would be enough to have significant output at lower frequencies.

 

[tinitus]

Looks similar to a W-frame system

It is
Someone created the "ripole" name fore commercial reasons

I think the original general describtion is "folded dipole"

I presented this, because I havent seen it this way before, with openings facing down and up
Drawing also shows kind of a marriage with H-frame, making the baffle effect more effective
Well, maybe kind of a dipole-omni hybrid

 

[chris661]

Here's a thought...

Instead of just folding the baffle once (ripole, S-frame, whatever you want to call it), why not fold it lots of times around the driver? You'd get some kind of spiral, not sure what that would do...
I don't know how you'd do it with 2 drivers, but it would be easy enough with one...
Chris

 

[GM]

http://www.diyaudio.com/forums/full-range/84026-cornu-spiral-copy-horn.html

 

[chris661]

Similar, but without the horn-related cross-sectional area changes.

 

[planet10]

Instead of just folding the baffle once (ripole, S-frame, whatever you want to call it), why not fold it lots of times around the driver? You'd get some kind of spiral, not sure what that would do...

Chris,

That is essentially what you get when you stack multiple ripoles

dave

 

[LineArray]

It is
Someone created the "ripole" name fore commercial reasons

I think the original general describtion is "folded dipole"

I presented this, because I havent seen it this way before, with openings facing down and up
Drawing also shows kind of a marriage with H-frame, making the baffle effect more effective
Well, maybe kind of a dipole-omni hybrid

Hi Tinitus,

such a dipole standing on the floor with sound particle direction
orthogonal to the floor would have poor efficiency IMO.

1) For a Transducer based on sound particle velocity, the
position near a wall (floor) is in general the most
disadvantageous you can choose, because sound
particle velocity near walls tends to zero and the room
modes cannot be excited efficiently from there.

A wall (floor) can support a dipole sub only if the direction
of sound particle velocity is parallel to the wall.


2) Direction of sound particle velocity is bad especially
for exciting the lowest room modes which are usually
in the horizontal plane, because distances of the side walls
are longer than the distance from floor to ceiling.

3) You loose IMO one major advantage of a dipole sub:
The possibility to balance excitation of room modes by
rotating the direction of particle velocity !
This is a unique balancing technique which cannot be done
using monopolar subwoofers. Monopoloar subs have to be
moved around to balance excitation of room modes.
Dipoles can move AND rotate to modify in room response.

This is an additional degree of freedom usable for balancing
in room response which cannot be over estimated IMO.

Kind Regards

 

[tinitus]

Hmm, ok, you seem to know this

But it seems to me that some kind of "omni" dipole might work well
At least the one Im listening to right now
But its not something I tried properly, yet

The one I showed was an attempt on that, an "omni" dipole
No, I dont expect it to be very loud
I never play loud

So, you saying that if its turned around, and playing along the side walls, it will be better
Ahh, we could call it Z-fold, or Zorro

 

[tinitus]

Our new friend Chris might want to read these

Offene Schallwand (OB)

DIY-dipole-1

 

[jacq.]

Well I had my idea on the subject a few years back for a Z frame, here is what it looked like below. It works great for music but as you mite guess the system as limited headroom.

Jacq.