Which 15 or 18 ınch woofer- best for open baffle

Thanks Mikkel! It looks to be quite a good one for the price, sadly it does not seem to sound good above 250hz or so. It seems the Eminence Kappalite II 2515 sounds good up to 1200hz. (Much more expensive) I might make a combination of the two. GRS for the low end up to 100hz Eminence for everything above that. My weeters can do 600hz so that should work i think.
 
Thanks Mikkel! It looks to be quite a good one for the price, sadly it does not seem to sound good above 250hz or so. It seems the Eminence Kappalite II 2515 sounds good up to 1200hz. (Much more expensive) I might make a combination of the two. GRS for the low end up to 100hz Eminence for everything above that. My weeters can do 600hz so that should work i think.

The woofers discussed are not to be used above 150-180hz.
Using the Eminence is a interresting choice. Problem is always to find the midrange driver that will go down to 150hz in OB. Let us know how it works if you go down that road.
If not then I can recommend the legendary monacor sp205-8. I use 3 in parallel. They will easily go down to 100hz, and can be used up to 3-5kHz (IMO). Don't be scared of the low price. They really sound good in OB. If you only want 1 driver, then the Beyma 10ag/n fullrange will also go down to 100Hz and sound good under 2kHz (IMO)
Mikkel
 
I actually have 4 of the Monacor drivers here! They are in my ceiling (so IB mounted) for surround sound. Been happy with them for that function. Maybe i should get them out and try them in an OB :)

And you are right, i was looking for a driver that can do <100 to 2/3khz or so. i want to use only a tweeter with it but one that can go quite low ~1khz. It seems the Eminence kappalite II 2515 is one of the few 15 inch drivers able to handle that range with any sort of clarity.

I will look some more into the Beyma, still trying to figure out what to build for my first open-baffle speakers.
 
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Yeah, Eminence DeltaLite II 2515. Great woofers for open-baffle.

Used by Troels in his OB-9. Why(?) I don't know. Looking at the tech specs from Eminence indicates a prime candidate for a vented box. The IEC response, which
is better yet performance than any open baffle could hope for, is -10db @ 50Hz, using 100Hz as a marker. 100Hz= 96db; 50Hz= 86db

I guess is that the OB-crowd likes to throw away at least 10db of sensitivity in order to be rid of that nasty evil box sound.

https://www.eminence.com/pdf/DeltaliteII_2515.pdf

OB9
 
>I guess is that the OB-crowd likes to throw away at least 10db of sensitivity in order to be rid of that nasty evil box sound.

That's because it is nasty and evil ;') I'm spoiled...

Also because amplification (sometimes with integrated DSP) is cheap. You can do things easily today that when I was a young man, were unobtainium.
 
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>I guess is that the OB-crowd likes to throw away at least 10db of sensitivity in order to be rid of that nasty evil box sound.

That's because it is nasty and evil ;') I'm spoiled...

Also because amplification (sometimes with integrated DSP) is cheap. You can do things easily today that when I was a young man, were unobtainium.

I agree totally, i used to be all about efficiency but these days you can get 300 watts good quality amplification for peanuts. There is a tipping point where, if you care about SQ, it's better to go with a design like open baffle and let brute force and/or dsp handle power needs.

The only limiting factor then is xmax. But at this kind of surface area (15 inch+) still more than enough volume even down low can be had. It certainly far exceeds my needs with just 2x 15" woofers.

That all being said if you want a lot of pressure below 40hz or so for movie effecs etc then yes, go with a closed sub. I have one that i only turn on for (some) movies.
 
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Can not convince the OB cultists, NEVER !!

Open baffle application for bass can never work. NEVER !!

Why? Because you are forever fighting the front-to-back cancellation.
You know, those pesky laws of physics.

Sure, you can put some patch-work on it; like you describe as dsp and horsepower, but you are still pixxing against the wind.

If y'all would open your mind instead of being duped by the cult, you could do some investigations, and follow the BBC research, to see what does, and what does not, contribute to the dreaded boxy sound. All I see is a bunch of rank amateurs too lazy to build a proper enclosure, and even if you weren't lazy, you wouldn't know how.

You're trying to adopt cone drivers NOT MEANT for open baffle/di-pole use, sprinkle some flooby dust in, and convince yourselves how good your "SQ" (sound quality) is. I heard a pair of those 15's once, in some kind of H-frame, powered with dsp and a **perfect** digital crossover. Sounded just like horse poop.

There are known ways to escape the trap of the dreaded boxy sound. Think about it, if OB was soooooo great, all the commercial manufacturers of speakers would have adopted the routine by now. But, they haven't. Well except for a very, very small number trying to capture a fringe market. Low distortion, high quality bass reproduction does not happen with a un-loaded cone flopping around on a plank of wood.

One of the most successful non boxy, open sounding speaker systems was the Mark Levinson HQD system. While not perfect, it went a long, long way of superior sound quality than what you guys are trying here. And YES, the important part of that system was di-pole, indeed.
 
J. Gordon Holt of Stereophile once wrote; "We were curious about the HQD but never requested one for testing because we felt that its $26,000 price tag put it in a class where it could only be of academic interest to 99% of our readers."

Nice reference example. At that price, it better have "superior sound quality than what you guys are trying here". I would hope so...

Everyone has their "cult" and one I can think of is the type of speaker that makes propagating bass. I'm sure we've all heard the cars that drive past our homes, whose walls and windows do nothing to restrict that type of wave. I can imagine someone's perception being as well hooked on that type of bass, as on any other. To where one might think, if it doesnt sail through cinder block walls like they're not even there, then it's not real bass.

Well there's another type of bass, where at the far field it's completely cancelled. Within the nearfield, it's very pleasant to listen to - at least I think so and so do a lot of others, which includes an actual expert in speaker design I've spoken with. Why would this guy have a set of 4, 18's in H frames, while being a, if not the MLTL design master? I'd say it's probably because they sound better to him. I mean imagine you master the art of a specific closed box design - and then dont even listen to that type of speaker anymore.

There must be something to it.

Sealed bass, T-line bass, Reflex bass, Passive-Radiator bass, Rear-Loaded Horn bass - and OB bass; they each have their peculiar sound character. Anyone's free to like or not like a particular electrical to air-coupling method, or it's actual characteristic sound and properties.
 
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I have found that OB/dipole bass is very room-size dependent. For example I built a system that used an M-frame per side, with 2 15" drivers per M-frame. In a moderately sized room, the bass mostly disappeared. The next day I demoed the same system in a room about 4 times as large, and the low esnd was completely different: weightier, full and present. People even asked me if I had re-worked the crossover overnight (I hadn't).

For this reason, I often advise people to consider using a sealed sub for the lowest couple of octaves, e.g. below 80-100Hz. This will take a lot of demand off of the woofer, which can operate from there up to 500-1k Hz. I use the Deltalite 2515 as a woofer in this band, but it has pretty limited Xmax and below 80Hz it's just not the right tool for the job. But as a large format midwoofer it is excellent.

If you can listen in a relatively large space, with some dimension of around 40 feet (10m) then you CAN run dipole bass all the way down to the mid 20s. It still will not pressurize the room and give you that sensation, but it can be very, very clean and pure sounding.
 
Open baffle bass is an art.

Never gonna be chest slamming visceral bass. But it can be very pleasant and accurate. What works in one room, may not in others. My Goldwood 1858 HFrames in the right room are awesome
In others, they are embarassing. I use sealed 12s with EQ now because I couldn't get those Goldwoods playing their best in my room. That said, I've still got them for a reason.

Also, the QTS of my driver's are higher than lots of drivers some others are discussing, and am sure this plays some role in their effectiveness or perceived effectiveness. Tho... If I were to do it again, I would go bigger and better quality, or at the very least, more Xmax so I can EQ my open baffle bass.
 
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Open baffle application for bass can never work. NEVER !!
LOL. I should introduce you to some pant leg flapping Open Baffles I've worked with. :D And some some crazy slamming coax OB my friend John has.

If you understand physics and acoustics, you can make OB bass work and work very well. But most people do not understand either, or choose to ignore them, and end up with anemic OB. I've heard far too many of them.

Open Baffle bass can work just fine if you understand how to do it. Taking the same approach as box bass is not going to get good results.