The final speakers will also be made, so I can make it closed if I really hate the OB sound, and if the possible powerresponse nightmare becomes reality.
Those are interesting looking. I believe your difficulty lies in the desire to meld dipole and omni in the same speaker. Their radiation patterns simply don't fit well together, IMO. I would encourage you to try one or the other, but aviod mixing them. They have some of the same propoerties in terms of soundstage and placement needs.
I believe what RAAL did was entirely monopole drivers firing in a lot of directions to create an omni radiation pattern. There is no dipole involved that I'm aware of. I've done a number of omni or hybrid omni-monopole designs and they can sound fabulous. Some of them can be seen at the link below. Perhaps these will give you some further ideas or inspiration. One of them, in fact, was inspired by a RAAL design shown at RMAF in 2009 or 2010.
Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com - dlneubec's Albums
I believe what RAAL did was entirely monopole drivers firing in a lot of directions to create an omni radiation pattern. There is no dipole involved that I'm aware of. I've done a number of omni or hybrid omni-monopole designs and they can sound fabulous. Some of them can be seen at the link below. Perhaps these will give you some further ideas or inspiration. One of them, in fact, was inspired by a RAAL design shown at RMAF in 2009 or 2010.
Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com - dlneubec's Albums
Member
Joined 2009
A lot of builders mix monopole bass and dipole mids/highs. I don't think it will be a big problem and it's certainly worth investigating. There is a short study on the topic at musicanddesign.com
Craw woofer
I agree, monopole and dipole together are common, but not omnipole and dipole, which is what the OP is proposing.
The RAAL sub is definately open baffle, one of the sides are open, and the others have 15" woofers
No it is not open baffle. It has 5 woofers and one open side and is configured as a u-frame cardoid, not an OB, so it doesn't have the open baffle figure 8 dispersion pattern. That is why it doesn't conflict with the omni dispersion pattern like a traditional OB would.
Hi Dan.
I've done a dipole midbass to a radial mid (..before you started on your fantastic designs). 😉 (..this was with 2 madison knight 10" drivers in parallel dipole to an audax pro mid radial, and then changed to Altec mid radial.)
Other than the differing pressure loss of both designs (radial and dipole), no different than what you would expect in the forward direction. Additionally, unlike a more traditional "sealed" mini-monitor above a dipole bass section, it doesn't display the forward compression that the mini-monitor has that would cause you to increase the level of the dipole (for a better subjective match).
I would note though that the radial mid was never "dipole" - that wouldn't work properly. (..eq. would be massive to counter the pressure loss, and/or you would need to move the crossover point up to the upper midrange for the open baffle.)
Then we have different understandings. OB for me and others is any open baffle, not just dipole
Here is what Raal said in the 6moons audio article about the Requisite Eternity speaker (see this link below for more)
6moons.com - industry features: RoadTour Serbia, Exit Raal
"This is a woofer housing. There will be 5 x 15" woofers and one hole. All that is, in fact, a U-baffle. I will use the acoustical resistance on the hole to get a cardioid dispersion pattern in the bass as I'm not a fan of the figure of 8 pattern." The latter, to interrupt our designer for a moment, is the well-known challenge of dipole panel and open-baffle speakers which suffer partial bass loss due to out-of-phase cancellation between the front and back wave. "In the cylinder above the woofers, there will be an 18 x 3" cylindrical array of full-range drivers serving as a midrange and one omni tweeter with 15 ribbons. About 170 cm tall in total. This speaker is named Eternity. This will be serial product, most probably run in small editions of 12 pairs each. My friend who designed and sculpted the woofer casting can make a different clay model after that, or make a custom sculpted surface for a pair. Each bass sphere pair takes 130 hours of work by the foundry plus 4 days of baking the molds. Sculpting is separate and not quantifiable.".
6moons.com - industry features: RoadTour Serbia, Exit Raal
"This is a woofer housing. There will be 5 x 15" woofers and one hole. All that is, in fact, a U-baffle. I will use the acoustical resistance on the hole to get a cardioid dispersion pattern in the bass as I'm not a fan of the figure of 8 pattern." The latter, to interrupt our designer for a moment, is the well-known challenge of dipole panel and open-baffle speakers which suffer partial bass loss due to out-of-phase cancellation between the front and back wave. "In the cylinder above the woofers, there will be an 18 x 3" cylindrical array of full-range drivers serving as a midrange and one omni tweeter with 15 ribbons. About 170 cm tall in total. This speaker is named Eternity. This will be serial product, most probably run in small editions of 12 pairs each. My friend who designed and sculpted the woofer casting can make a different clay model after that, or make a custom sculpted surface for a pair. Each bass sphere pair takes 130 hours of work by the foundry plus 4 days of baking the molds. Sculpting is separate and not quantifiable.".
yes I have read it all, but this is just a matter of words, and not the intention with this thread to discuss what is OB and what is not.
OB means 'open baffle', mounting a driver on a simple plane baffle, big or small
dipole is a general term descibing just about every desing with 'open back', H-frame, folded or whatever, and OB included
dipole is a general term descibing just about every desing with 'open back', H-frame, folded or whatever, and OB included
I don't agree. Dipole is the radiating characteristic "figure of eight", and other types damped u-frame, ripole et al have other radiating characteristics. I haven't come across a precise definition, but only a lot of different opinions.
From linkwitz "Since this is an open baffle, bi-directionally radiating dipole speaker"
PHOENIX - Open Baffle Loudspeaker
I read this as the open baffle is the top level, like boxed speakes.
Open baffle is then divided in to - flat baffle, u-frame, w-frame, H-frame, tube etc. characterized with different radiating patternes like cardioid, dipole and combinations like the ripole.
Boxed speakers is divided in closed box, vented (including variovent), horn loaded
Also Nao and other resources seems to see things this way.
The open baffle speaker circle is also an example of this. Otherwise it should have been called dipole speaker circle
Last edited:
ok, I see your point 😉
very old arguement
that neither dipoles nor omnis exists in real life, in normal listening room
but its like saying that a horse is no longer a horse once its tamed, only wild Mustangs are real horses 😀
That's also why I mentioned it's not the topic of this thread. Simply because thare are no way we will ever agree.
The same thing happens back in the old days, were I advocated for class d to be called analog and not digital. Obviously I lost that fight, since class d today i broadly accepted to be "digital".
Maybe we should invent a new term, that can't be miunderstood.
What about "Open Cabinet Speakers Except Vented Ones But Inkluding Plane Baffle" or OCSEVOBIPB in short.
hey, doesnt have to be that complicated 😀
actually, we have all the terms we need
unless you demand 'perfection'
I will give it one last try
and it goes like this
the only genuine dipole is the OB, a plane baffle
and all other terms describe variations
and their compromises
tho not having perfect dipole polar pattern, those 'variations' still have enough OB 'soul' to be in the famely
I think we have just about perfect 'terms' to descibe what we are talking about
or at least until we start making a mess out of them
ho ho 😀No doubt that the original OB is the plane baffle with dipole figure of eight pattern.
So we definately agree that this is the mother of all OB's.
So we definately agree that this is the mother of all OB's.
You were right about that, too, but . . . 🙁
OB is just what the words say . . . any "open", or "incompletely enclosed", driver ("ports" excepted). "Dipole" is a particular radiation pattern, usually accomplished by "open baffle" mounting of a single bidirectional driver, but also possible with paired enclosed drivers separated by a baffle, if that produces the classic dipole lobe shape and cancellation . . .
- Status
- Not open for further replies.