That was the best system I heard at BAF2011. I had not yet been impressed by Lowthers, they always sounded way too bright and forward to me. In this system, however, they sounded very natural.
The bass was open and detailed, the way open baffle bass should be. The music being played didn't go terribly deep, so I can't comment on how low they go.
The baffles were huge, really only suitable for a very large man-cave
The bass was open and detailed, the way open baffle bass should be. The music being played didn't go terribly deep, so I can't comment on how low they go.
The baffles were huge, really only suitable for a very large man-cave
Dear Mr Nelson,
I am looking for an open baffle design which can be placed close to the wall. Does this one work if placed directly next to the wall with the slot facing away from the wall? I am also thinking of a fairly narrow front baffle maybe around 30~40cm.
Would this work in this scenario?
Oon
I am looking for an open baffle design which can be placed close to the wall. Does this one work if placed directly next to the wall with the slot facing away from the wall? I am also thinking of a fairly narrow front baffle maybe around 30~40cm.
Would this work in this scenario?
Oon
Have you seen this:
http://www.linkwitzlab.com/images/graphics/corner-dp.gif
Or this:
http://www.diyaudio.com/forums/multi-way/10962-stereolith-loudspeakers-question-67.html#post2732948
(It began with that post and lasted several pages after that. Good read... )
http://www.linkwitzlab.com/images/graphics/corner-dp.gif
Or this:
http://www.diyaudio.com/forums/multi-way/10962-stereolith-loudspeakers-question-67.html#post2732948
(It began with that post and lasted several pages after that. Good read... )
The oldest guys in that. They had the Aquarius wide dispersion range before L100. Pro sub manifolds, every floor facing sub, even a Karlson, all kinda ''slotty''
actually the jensen transflex predates all these "slot approaches" mentioned thus far, as i recall.
harry olsen might have done some even earlier stuff.
we refer to the transflex now as the TH.
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I took a saw...
http://www.diyaudio.com/forums/full...-b200-eminence-beta-15-ob-14.html#post2755123
Impressions tomorrow...gotta sleep now...
http://www.diyaudio.com/forums/full...-b200-eminence-beta-15-ob-14.html#post2755123
Impressions tomorrow...gotta sleep now...
Hi,
I have read this thread with great interest.
I have owned Heil dipole AMTs since the mid seventies. For years I tried every different type of system for the mid/bass (sealed, vented, tl, etc - ok no horns) and in frustration turned to open baffles in the late 70s early 80s ( I can't remember exactly when). Once I tried OBs I was hooked and since I owned AMTs I inevitably tried to emulate them with dynamic drivers (up to 4x15" per side) - I ended up buildng a lot of baffles and used a lot of MDF, high-density chipboard, and hardwood. One of the designs did not look that different from what Nelson posted - what was that about enough monkeys with power tools?
Anyhow at that time I was convinced that a lot of my problems with boxes was the cabinet resonances of the panels and modes within the boxes (this sort of thing was in vogue then whereas OBs were not). So I reasoned that the easiest way to eliminate the box colouration was to eliminate the box. A quick peruse through Olson, Beranek and Gilbert Briggs and the stage was set.
The dipole/monopole radiation pattern transition problem was obvious in retrospect and after trying my first crude cobbled together full range dipoles I was kicking myself for not seeing it but miss it I did!
To cut the story short, in all my playing with dipoles I always returned to the simple small OB, i.e. where the driver is operated on the slope only. In the end the system morphed to AMT, 6.5inch on 8 inch or so (rounded corners) square baffle, 15inch on 22 inch square (rounded corners) baffle, and single sealed sub for the last couple of octaves when necessitated by the type of music.
So after all this blurb, my question is: does anyone here think that the large wooden panels used in OBs contribute audible colouration due to panel resonances? I know that the available excitation is much lower than a box but many of the OBs I see are largely unsupported and unbraced so they will be very susceptible to resonance. The excitation can be from direct transfer form the drivers or by acoustic transfer from the air. It was this perceived problem with panel. resonance that always turned me back to small baffles which have little chance of audible resonances but was I right or wrong to reject the rest?
Just in case you are still following this thread, Nelson. I was wondering if you could shed some light on your experiences with Dr Heil and at ESS. There is really very little information on the AMTs (outside Dr Heil's patents which are quite informative if you read them enough times to get past the peculiar English) with any substance at all, even the Beyma JAES papers are remarkably disappointing. The only other person I have seen apart from yourself associated with the Heil AMT is: Michael Thompson | LinkedIn
and I am not going to join linkedin just to get a contact for him. Obviously the best place for such a post would be over in Planar and Exotics.
Still, the main point of this post is the OB resonance question.
Regards,
Bob
BTW
How do you set up a sig on this forum? For now a crude method
I have read this thread with great interest.
I have owned Heil dipole AMTs since the mid seventies. For years I tried every different type of system for the mid/bass (sealed, vented, tl, etc - ok no horns) and in frustration turned to open baffles in the late 70s early 80s ( I can't remember exactly when). Once I tried OBs I was hooked and since I owned AMTs I inevitably tried to emulate them with dynamic drivers (up to 4x15" per side) - I ended up buildng a lot of baffles and used a lot of MDF, high-density chipboard, and hardwood. One of the designs did not look that different from what Nelson posted - what was that about enough monkeys with power tools?
Anyhow at that time I was convinced that a lot of my problems with boxes was the cabinet resonances of the panels and modes within the boxes (this sort of thing was in vogue then whereas OBs were not). So I reasoned that the easiest way to eliminate the box colouration was to eliminate the box. A quick peruse through Olson, Beranek and Gilbert Briggs and the stage was set.
The dipole/monopole radiation pattern transition problem was obvious in retrospect and after trying my first crude cobbled together full range dipoles I was kicking myself for not seeing it but miss it I did!
To cut the story short, in all my playing with dipoles I always returned to the simple small OB, i.e. where the driver is operated on the slope only. In the end the system morphed to AMT, 6.5inch on 8 inch or so (rounded corners) square baffle, 15inch on 22 inch square (rounded corners) baffle, and single sealed sub for the last couple of octaves when necessitated by the type of music.
So after all this blurb, my question is: does anyone here think that the large wooden panels used in OBs contribute audible colouration due to panel resonances? I know that the available excitation is much lower than a box but many of the OBs I see are largely unsupported and unbraced so they will be very susceptible to resonance. The excitation can be from direct transfer form the drivers or by acoustic transfer from the air. It was this perceived problem with panel. resonance that always turned me back to small baffles which have little chance of audible resonances but was I right or wrong to reject the rest?
Just in case you are still following this thread, Nelson. I was wondering if you could shed some light on your experiences with Dr Heil and at ESS. There is really very little information on the AMTs (outside Dr Heil's patents which are quite informative if you read them enough times to get past the peculiar English) with any substance at all, even the Beyma JAES papers are remarkably disappointing. The only other person I have seen apart from yourself associated with the Heil AMT is: Michael Thompson | LinkedIn
and I am not going to join linkedin just to get a contact for him. Obviously the best place for such a post would be over in Planar and Exotics.
Still, the main point of this post is the OB resonance question.
Regards,
Bob
BTW
How do you set up a sig on this forum? For now a crude method
Using a term like nonlinear science is like referring to the bulk of zoology as the study of non-elephant animals. - Stanislaw Ulam
I guess that's already been addressed.
A slot has its own (pipe) resonance, so it'd be better used as a sub, xovered low enough to avoid that.
Other than that, the slot can be a much tighter package within the same (effective) baffle area.
As to the vibration on baffle itself, there're so many other factors involved.
Hi CLS,
I was aware of the slot resonance. As someone who has played around with small pipe organs and similar instruments I was well aware of the resonance of a stopped pipe ans as you said it has been covered a lot in this thread.
I was referring to panel resonance at drumhead frequencies as well as the higher modes. I was not really after a technical discussion as much as one based on listening and perception.
In this case Nelson has mounted his woofers and his mid/treble on one large baffle. The large baffle not only increases path-length before cancellation in the bass it also acts as a relatively infinite baffle at high frequencies which means it is an acoustic barrier ( assumes wide dispersion from the driver). BUT, it is also a large soundboard (to use a musical instrument term). Many OBs have baffles that are larger than the sound board of a Steinway D, even larger than a Bosendorfer Imperial. Also they are often made out of ply which is quite resonant, obviously not as resonant as a spruce soundboard but still resonant. I suppose it is a question of coupling (mechanical and acoustic) and audibility of any results.
Hopefully, those who have built OBs can comment from a subjective viewpoint (or technical if they wish).
Regards,
Bob
Using a term like nonlinear science is like referring to the bulk of zoology as the study of non-elephant animals. - Stanislaw Ulam
I was aware of the slot resonance. As someone who has played around with small pipe organs and similar instruments I was well aware of the resonance of a stopped pipe ans as you said it has been covered a lot in this thread.
I was referring to panel resonance at drumhead frequencies as well as the higher modes. I was not really after a technical discussion as much as one based on listening and perception.
In this case Nelson has mounted his woofers and his mid/treble on one large baffle. The large baffle not only increases path-length before cancellation in the bass it also acts as a relatively infinite baffle at high frequencies which means it is an acoustic barrier ( assumes wide dispersion from the driver). BUT, it is also a large soundboard (to use a musical instrument term). Many OBs have baffles that are larger than the sound board of a Steinway D, even larger than a Bosendorfer Imperial. Also they are often made out of ply which is quite resonant, obviously not as resonant as a spruce soundboard but still resonant. I suppose it is a question of coupling (mechanical and acoustic) and audibility of any results.
Hopefully, those who have built OBs can comment from a subjective viewpoint (or technical if they wish).
Regards,
Bob
Using a term like nonlinear science is like referring to the bulk of zoology as the study of non-elephant animals. - Stanislaw Ulam
Hi Fokes, I'm looking at this design concept and it looks like a good simple approach to some custom speaker installation I'm looking to integrate into a system I'm building. I figure since there are so many experienced diy'ers around I might capture some suggestions or feedback.
The photo below sketches the basic situation. The wall area involved is 6'x8', below 3' of rack/shelving under a 9'4" ceiling. This area will have a quilted cloth material over 4" rock wool.
Anchored into the left side of the frame will be three 6.5 foot shelves. The top one will be about a foot of space for audio/video rcvrs/players/amps. Below that is 14" space for stereo sub-woof and center channel for surround. The space is about 16" deep. About 26" below that will be a shelf for the stereo monitors a video screen. The room is about 9x10x11 feet wide, with a bay-window shaped wall opposite.
Enough detail. This slot-loaded speaker looks simple enough for my limited shop tools and looks to be simple to tune and modify after the fact.
What I want to know if there are any gotchas to look out for in my situation. I read the first half of this thread and scanned the rest, so I'm not totally in the dark. At this point I would like either build a passive low pass filter and have phase control, or buy some inexpensive active controller.
One idea I have is to build a passive small-signal pass filter/controller before the power amp. Is there any reason not to do this?
Any ideas appreciated ;-)
The photo below sketches the basic situation. The wall area involved is 6'x8', below 3' of rack/shelving under a 9'4" ceiling. This area will have a quilted cloth material over 4" rock wool.
Anchored into the left side of the frame will be three 6.5 foot shelves. The top one will be about a foot of space for audio/video rcvrs/players/amps. Below that is 14" space for stereo sub-woof and center channel for surround. The space is about 16" deep. About 26" below that will be a shelf for the stereo monitors a video screen. The room is about 9x10x11 feet wide, with a bay-window shaped wall opposite.
Enough detail. This slot-loaded speaker looks simple enough for my limited shop tools and looks to be simple to tune and modify after the fact.
What I want to know if there are any gotchas to look out for in my situation. I read the first half of this thread and scanned the rest, so I'm not totally in the dark. At this point I would like either build a passive low pass filter and have phase control, or buy some inexpensive active controller.
One idea I have is to build a passive small-signal pass filter/controller before the power amp. Is there any reason not to do this?
Any ideas appreciated ;-)
Attachments
Nevermind about the small:large signal. I think small signal EQ would give the power amp an easier time.
I left out the details of using a pair of 10" woofers for this, and a 10" coaxial woofer/tweeter for the center channel. At this point I think I'll go with an open baffle for them, with a slot in the woofer baffles.
I left out the details of using a pair of 10" woofers for this, and a 10" coaxial woofer/tweeter for the center channel. At this point I think I'll go with an open baffle for them, with a slot in the woofer baffles.
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