My New Dipoles

[ra7]

Once you start looking at the efficiency and excursion trade-offs the 'naked dipole' folks have to make, it no longer makes sense, at least to me. Yes, you get perfect polars. But good sound is more than perfect polars. Music requires dynamics, which these designs will simply not do.

[DYNABLASTERTUNERS]

you think that this OB lacks dynamics? he he
http://www.hifi-forum.de/index.php?a...4&thread=22807

[Bob Brines]

Let me point out that the failure of the the OB/H-baffle combination in my scenario was not the OB's. They performed pretty much as I had anticipated. The problem was my failure to understand the limitations of the H-frames. I had expected to run the H-frames up to the OB's. I now know that ~70Hz is as high as this particular configuration can go. In a word, the boxes I build will NEVER work with an OB.

I don't doubt that a big baffle OB would work with these drivers, but that is not my goal. Going with small baffle OB's of reasonable size (to me!) requires a bass speaker that can to up to the required 300Hz, or at least 200Hz it I increased the size of OB's by double -- not something i want to do. I think I mentioned above that I am looking at the Dayton RSS315HF in something like 3'^3 sealed. this would easily go high enough and would also go easily into the 20's in room.

But time is short before LSAF, so that will have to wait until summer.

Bob

[ra7]

Originally Posted by DYNABLASTERTUNERS

you think that this OB lacks dynamics? he he
http://www.hifi-forum.de/index.php?a...4&thread=22807

First, that is not nude. Second, I have very similar drivers (AN8 and Deltalite 2515II) and I've mated them on an OB. You need plenty of EQ below 100 Hz. The Kappalite does have more excursion, but that is exactly what I mean. As you go for better drivers (lower Qts, bigger magnets, better midbass), you need a bigger baffle to keep the EQ to a respectable level. Nothing wrong with building bigger baffles. But with nude, you are looking at serious power. I want to go in the other direction, higher efficiency, less excursion, less distortion, better Class A amps. IMO, this is more elegant.

Although, the choice of drivers in that design is top notch. Plenty of efficiency to throw away before it starts getting serious. Well done. Bet it sounds good.

[planet10]

Originally Posted by soundaatma

with none of the boxless spacious sound of a full spectrum OB speaker.

Or any of the problams an OB introduces. One of the boxiest speakers i've ever heard was an OB.

Every loudspeaker has its wn set of issues.

dave

[wron]

The open baffle midrange design concept has never appealed to me even though there are enough open baffle (dipole) mid/ box bass (omni) designs out there, I assume for practical (size) reasons.
My original inspiration for open baffle design was the Celestion 6000 system. Celestion System 6000 loudspeaker system | Stereophile.com
At the time (25 years ago) mini-monitors (Proac Tablette and Elipsion 1400) were my cuppa tea since they removed the leaden boxy bass I disliked.
The Celestion system offered the best of both worlds but required bespoke electronic x-overs which did not appeal to my DIY sensiblities. I did build a 3-way open baffle system 15 years ago but could never get a handle on the open midrange. The bass was remarkably "detailed" - free from colouration.
I've built a number of speakers since, learning much on these type of internet forums. I am now building an open baffle bass/mid-bass reflex system returning to my original inspiration: the Celestion system. I've spent the winter building the cabinents so my plan is to work on the x-over over the spring and summer using a fullrange driver in the bass reflex portion to keep things simple.
I hope this post gives others some alternative design ideas for open baffle bass.

Ron
Listening to: The Long Ryders - Native Sons

[chrisb]

Originally Posted by planet10

Or any of the problams an OB introduces. One of the boxiest speakers i've ever heard was an OB.

Every loudspeaker has its own set of issues.

dave

let me second guess the "boxiest" comment - very coloured /closed in midrange was what I heard - due I think to a "perfect storm" - combination of XO frequency & slopes & component quality, and quality of compression driver on specific co-ax driver (actually not too much unlike what I found with the Hammer Dynamics Super12 - so I don't think it's a simple issue of "enclosure" or lack thereof)

my biggest issue with any OB the sound with which I could fall in love (there have been a couple), was finding a space to live with them after being kicked out - "not in MY home you don't" - and y'all can save your time on the relationship advice - it's all a compromise, and after 40yrs in the same one, I know how good I've got it.

[badman]

Yes indeed. They require the right room. That's the funny thing, is that big speakers that can control directivity better, with all the advantages that brings, are most needed in small rooms. With dipoles, you have to assume several feet of clearance as part of the speaker, it's not optional. The alternative is horns- more speaker but can be butted right up against the back wall. Either way it's a lot of real estate to use speakers that minimize the room.

God bless my wife, I get to do pretty much whatever I want, which means HUGE.

[Godzilla]

I'm divorcing my wife (17 years) and keeping the big OB speakers.

[Vix]

Hi,

Looks like the open baffle speakers must be either loved or hated! I did both
When I built my OB's, they were essentially a copy of Visaton No box design:
The VISATON NoBox BB Loudspeaker Kit Review By Dick Olsher

But I didn't like them., With its crossover points and big side wings, bass was muddy and even honky, there was some resonance I couldn't stand...
5 years later and a lot of experimentation, I ended up with the ones as you see on pics. Removed the wings, but added front "slot". Yes, they are ugly, but I don't care. It was "quick n'dirty" test that worked so I left it as it was. (The Slot idea came from Nelson Pass OB's-thanks!). Also, the crossover got a lot of rework. Now it's active, with the high pass set on 150 Hz 2nd order, and Low Pass (with boost) at 80 hz, 2nd order. Hint: Read Nelson Pass article:The Slot Loaded Open Baffle Project Article By Nelson Pass

What Bob has done, looks more like a "Fast" concept, with a fullranger and a bass support, bass being an H-frame OB- not bad...