Open Baffle Speakers

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#2
there is loadsof material on the web on OBs
however this coming from Troels is important:
"Well, the OBL-11 was sold a few years ago (space issue) and I'd forgotten what a 15" on an open baffle does. I knew it was good, but that good? Frankly, it beats any other construction on these pages regardless of price. None of my other speakers even comes close to this. Listening to Niels Henning Ørsted Pedersen on This Is All I Ask, track four, "Just In Time", and you'll know what I mean. The articulation in lower registers is phenomenal and overall dynamics scary. This is close to what an upright bass should sound like. Even the best 10-inch bass in a bass reflex box will never be able to deliver such detail and transient response. Never!"
 
#3
Ob sound most real of all speakers especially with powerfully s.e.t.
I have a grand piano and with the window opened neighbour thought it was my grand piano playing

Ob cost lot have more natural and harmonics

They need huge bords to have any decent bass output
3 way designs or more speakers

Good closed speakers will be more coherent with complex music more conservative
 
#5
Thanks guys,
I've been playing around with horns and have been thinking about using OB for bass and my horns for mid.....
I built Troels's DTQWT speakers a few years ago and love them. Just want to try something new.....

Really looking for thoughts and impressions from someone thats made them, but the i suppose open baffles are open baffles. Right??

Cheers Dave
 
#7
I have indeed experimented with large woofers on panels like this...unfortunately while proponents gush about the "airiness" and other platitudes about open baffles, they don't test well. The locations within the room can be a make or break option....note in this picture, the right side of the panel is very close to a wall...and fully flush with the floor. Those two structures "hook" the woofer so that the rarefied pressure wave can't swing around & cancel out the positive pressure wave.
It seems these creations seem best at home with these big drivers, a plain board....in a small room....those big drivers flailing away.



-------------------------------------------------------------------Rick............
 
#12
kevinahcc20 said:
If you want to study OBs you will want to spend some time at Linkwitzlab.com.
Click to expand...

...which brings up an important point that I would like to hear from the OB-experienced, please.

Notice how wide are the Troels OBL-15 baffles. And how narrow is Linkwitz' latest LX521 baffle.

I had a good look at Linkwitz' latest baffle. I am currently using an open baffle on a 10" pro mid-bass at home for 220-1200 Hz. Therefore I am very keenly interested in what Linkwitz did and the shape he developed around his larger mid driver.

But, I must say, I am surprised by the resulting shape. Linkitz wrote that his objective was constant beamwidth. Does it make any sense, from a theoretical point of view, why such a shape would be more constant-beamwidth than, say, a simple rectangle?

Also, I don't understand this use of extremely narrow baffles on open baffle drivers running into the 200-1000 Hz range. Linkwitz writes on his LX521 page, "For a controlled horizontal polar response the baffle must be narrow...". I thought you would get multiple lobing ***on-axis*** as the back wave reaches around to the front. I thought that would be a huge problem and would need to be addressed first. That is why the centre of my 10" is at least 300mm from any baffle edges. Have I been unnecessarily oversizing my baffle? How can a super-small open baffle work in this frequency range? Linkwitz seems quite unperturbed. I would like to go there if I can get away with it.

cheers
 
#15
zmyrna said:
I have criticism for latest Linkwitz design:
If one comes to the conclusion that the narrower the baffle the better it is, than the natural solution is no baffle at all (nude driver, magnet mounted or hanged)
No need to experiment with silly minimalist baffle shapes.
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No conclusion like that is made by SL or on the Linkwitz site. Quite the contrary, he elaborates on why the baffle should NOT be circular and how to optimize radiation pattern using nominally sized rectangular baffles that are easily fabricated by a handy DIY'er.

The essence of the Linkwitz designs....relative to large-baffle designs where a driver is placed in the middle of a large piece of plywood.... seems to fly over the head of many potential users. 🙂
Most users seem to zero-in on the extensive equalization required, driver excursion, etc, etc, and don't realize those are the final portions of the design. Much experimentation was done initially to identify a suitable baffle shape before any of the electronics was considered.

Cheers,

Dave.
 
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#17
Davey said:
No conclusion like that is made by SL or on the Linkwitz site. Quite the contrary, he elaborates on why the baffle should NOT be circular and how to optimize radiation pattern using nominally sized rectangular baffles.
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Thank you. So, why doesn't he use normally sized baffles?

The essence of the Linkwitz designs....relative to large-baffle designs where a driver is placed in the middle of a large piece of plywood.... seems to fly over the head of many potential users. 🙂

Dave.
Click to expand...

I am trying to understand. What does the (unequalised) axial response look like with a LX521 baffle? Does it not have a series of nulls?
 
#19
In designs like SL's and mine baffle size and shape is more a function of radiation pattern over the intended useful bandwidth and the allowable eq. Typical wide baffle, open baffle designs pay little attention to radiation pattern.
 
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#20
Davey said:
No conclusion like that is made by SL or on the Linkwitz site. Quite the contrary, he elaborates on why the baffle should NOT be circular and how to optimize radiation pattern using nominally sized rectangular baffles that are easily fabricated by a handy DIY'er.

The essence of the Linkwitz designs....relative to large-baffle designs where a driver is placed in the middle of a large piece of plywood.... seems to fly over the head of many potential users. 🙂
Most users seem to zero-in on the extensive equalization required, driver excursion, etc, etc, and don't realize those are the final portions of the design. Much experimentation was done initially to identify a suitable baffle shape before any of the electronics was considered.

Cheers,

Dave.
Click to expand...

Linkwitz says narrow baffle is good.
But anybody who has measured an OB can tell you that no-baffle measures better than narrow baffle. So what is the point of a narrow baffle? 1db LF gain?

In my book:
1. best of both world solution = felt baffle (for mid)
2. choose your evil solution = large baffle with asymmetrical driver placement OR no-baffle
3. pointless non-solution = minimalist baffle with silly shape
 
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