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zobsky 14th September 2007 01:58 PM

Dipole Sub question
 
What's the difference between the linkwitz W dipole and the dual driver ripole (apart from driver orientation)?

Thanks

http://www.lautsprechershop.de/hifi/images/aka_gdp.gif

chops 14th September 2007 02:18 PM

Isn't the ripole somewhat smaller and doesn't it in some way lower the Fs of the driver due to the way it loads the driver?

AFAIK, a dipole doesn't do anything to the Fs and doesn't really load the driver at all.

Rudolf 14th September 2007 03:33 PM

The Linkwitz W dipole tries to cancel non-harmonic distortions by running the drivers push-pull. But the construction leads to front and rear air volumes that are very different for both drivers. So symmetry in frequency response is questionable.
The ripole favoures driver symmetry. Usually ripoles load the drivers by minimizing the front cavity. This leads to a lowered fs and transfers the onset of the dipole roll off to lower frequencies too.

In some way the ripole approaches a dipole made of two very short transmission lines while the Linkwitz W is more like a folded OB.

zobsky 14th September 2007 03:34 PM

i agree re. the smaller dimensions loading a ripole. I just hadn't ever seen a dual driver ripole before .Before seeing this diagram, I'd always thought a ripole had to be a N-profile, and in order to use multiple drivers in a ripole, each driver would need it's OWN N-profile enclosure.


Chops, off topic, ..doyou still use your U-baffle subs and did you ever try your drivers in a W-profile or ripole enclosure?
Secondly,(Dipole noob alert :att'n: ) can't a W-profile sub work with the driver cones facing each other? Why are the drivers always mounted looking in the same direction ?

Thanks

theAnonymous1 14th September 2007 05:09 PM

Quote:

Originally posted by zobsky
Secondly,(Dipole noob alert :att'n: ) can't a W-profile sub work with the driver cones facing each other? Why are the drivers always mounted looking in the same direction ?

Quote:

Originally posted by Rudolf
The Linkwitz W dipole tries to cancel non-harmonic distortions by running the drivers push-pull. But the construction leads to front and rear air volumes that are very different for both drivers. So symmetry in frequency response is questionable.


y8s 14th September 2007 08:03 PM

Quote:

Originally posted by zobsky
i agree re. the smaller dimensions loading a ripole. I just hadn't ever seen a dual driver ripole before .Before seeing this diagram, I'd always thought a ripole had to be a N-profile, and in order to use multiple drivers in a ripole, each driver would need it's OWN N-profile enclosure.
I think the behavior of the mirrored ripoles would be unchanged with or without a central wall. each driver would see the same pressure wave as it would have with a wall there or not. either it's produced by a second driver (in phase of course) or a reflection of its own output.

so who has done testing on the response of a Linkwitz spooning woofer W compared to a ripole facing woofer W? And how do you design the "lowered Fs" portion of the latter to gain extension?

Matt

zobsky 14th September 2007 08:13 PM

Quote:

Originally posted by y8s


so who has done testing on the response of a Linkwitz spooning woofer W compared to a ripole facing woofer W? And how do you design the "lowered Fs" portion of the latter to gain extension?

Matt

Potentially my investigation for next month, IF I can find 4 acceptable woofers less than $35 shipped. I'd like to get down to an honest 30Hz wiithout excessively loose flabby bass but don't want to resort to low Q drivers + Eq.

Would these work ?
http://www.partsexpress.com/pe/showd...number=290-346

theAnonymous1 14th September 2007 08:36 PM

If you can swing a bit more :$:, these would be a better choice....

http://www.partsexpress.com/pe/pshow...TOKEN=59432710

I have 4 of them waiting to be put in ripoles. I have no way to cut the wood though, so it won't happen anytime soon (it's been over a year so far).

zobsky 14th September 2007 11:20 PM

Quote:

Originally posted by theAnonymous1
If you can swing a bit more :$:, these would be a better choice....

http://www.partsexpress.com/pe/pshow...TOKEN=59432710

I have 4 of them waiting to be put in ripoles. I have no way to cut the wood though, so it won't happen anytime soon (it's been over a year so far).

Okay, .. I picked up 4 of those drivers for ripole (or more likely w baffle use). I'm hoping that the Qts of 0.7 will give me some bass without having to resort to EQ. Let's see what happens next month when the sawdust flies.

I'll be eating out of a can of beans for the rest of this month :)

johninCR 15th September 2007 02:15 AM

With 4 drivers you can easily get the ripole symmetry in a W layout, so you get the ripole benefits along with vibration cancellation and push/pull distortion reduction all in one, not to mention about the smallest cab possible. HINT, the thicker the driver mounting panels the narrower your cab can be....It's kinda counter intuitive, but true as long as you mount the drivers normally in relation to the holes. Also, plan your build to be bolted together, so you can always get to your drivers to remove or change them without destroying the cab.


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