Open Baffle "Cabinets"

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Open Baffle "Cabinets"

Postby Slinco » Sun Feb 10, 2008 12:10 pm

For awhile now I've been intrigued by the Auditorium 23 SoloVox speaker. It's an open baffle design with unique "wings" on the back to deflect most of the rear wave to the sides. here's a picture of the back side of one...
Image

And then today I came across this speaker from a company called Schallwand in germany...Image
It's similar in a lot of ways, and got me thinking about ways to do this with the Hawthorne drivers, and what, if any, the benefits would be. Seems to me if most of the back wave is going to the side walls you'd have more of a delay before your ears heard it, which should be a good thing, right? And you'd be able to place them closer to the front wall.
I would think curved deflectors would be best, and they could be easily made by cutting them out of a hunk of Sonotube from the home improvement store.

Any thoughts?
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Re: Open Baffle "Cabinets"

Postby hurdy_gurdyman » Sun Feb 10, 2008 3:25 pm

I think a lot would be room dependent. One should try making some inexpensive MDF guides and try it on the cheap before investing in any great expense. Some rooms may like this approach, while other rooms might have a problem with it.

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Re: Open Baffle "Cabinets"

Postby Bob in St. Louis » Mon Feb 11, 2008 9:27 am

Interesting Idea Steve. I wonder if mounting the rear wings on dowel rod pivot points might be a cool tuning aid. You could swing the wings in and out like shutters or saloon doors.
Hmmmm :-k

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Re: Open Baffle "Cabinets"

Postby hurdy_gurdyman » Mon Feb 11, 2008 10:14 am

Bob in St. Louis wrote:Interesting Idea Steve. I wonder if mounting the rear wings on dowel rod pivot points might be a cool tuning aid. You could swing the wings in and out like shutters or saloon doors.
Hmmmm :-k

Anything hinged would have to be very rigidly mounted to prevent vibrations.

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Re: Open Baffle "Cabinets"

Postby hurdy_gurdyman » Mon Feb 11, 2008 10:23 am

One of the big reasons OB's sound as good as they do is the figure 8 response pattern. This puts a null off to the sides, greatly reducing side wall reflections. The wings shown would cancel a lot of this effect, thus giving a radiating pattern quite a bit different. I suspect the room used in will be a major factor in this. A typical room already works well with a straight dipole, so its possible the winged baffle shown would make matters worse instead of better. It may take a particular set up to use this to advantage. Again, I'd want to do a lot of inexpensive trial and error before investing a lot in it. Maybe it would be great, but there is probably a reason everyone hasn't jumped on this idea already, seeing as its been out a while.

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Re: Open Baffle "Cabinets"

Postby corloc » Mon Feb 11, 2008 10:28 am

Hello, I have recently acquired an SI from my father-in-law for my birthday,(Great Gift). :D I am going to be building a monaural system for my living room. I have to put the speaker close to the wall, so I've been working on this.

http://www.hawthorneaudio.com/photos/displayimage.php?album=lastup&cat=10061&pos=0

24" x 17" x 37"

I know it doesn't show it in the picture, but the sides of the cabinet are completely open. The back of the baffle would have dampening material to stop reflections, and the defector would be highly reflective and filled with sand. I'm hoping to build a mule when it gets a little warmer.

I thought about useing similar cabinets to your pictures for my B200's, but I don't know how they get away with no damping material behind the baffle. My biggest concern with useing those cabs with the SI is the 15" driver moves a lot more air than an 8" and I think it would really muddle the sound. I'm no even sure my idea will work.

Chris
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Re: Open Baffle "Cabinets"

Postby Slinco » Mon Feb 11, 2008 11:08 am

Good points everybody. The SoloVox has been very positively reviewed many times (there's some review links here http://www.toneimports.com/auditorium23/a23Solovox.html ), but they do all seem to mention "careful placement" is necessary. But then again all speaker reviews seem to mention that, and I've never heard much difference moving speakers around. But my ears are far from "golden". The reviewers also all talk about how these speakers "disappear' more convincingly than anything they've heard before, which I would think has something to do with how the back wave is "shaped".
I think I'll give something like this a try at some point. One of the reasons I like the idea is because the front wall behind my speakers is mostly glass, with no curtains, and obviously HIGHLY reflective. I like the idea of deflecting the back wave out to the sides, or even up to the ceiling some way or another.

Chris, keep us posted if you give your idea a try.
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Re: Open Baffle "Cabinets"

Postby Darrel Hawthorne » Mon Feb 11, 2008 11:11 am

corloc wrote:Hello, I have recently acquired an SI from my father-in-law for my birthday,(Great Gift). :D I am going to be building a monaural system for my living room. I have to put the speaker close to the wall, so I've been working on this.

http://www.hawthorneaudio.com/photos/displayimage.php?album=lastup&cat=10061&pos=0

24" x 17" x 37"

I know it doesn't show it in the picture, but the sides of the cabinet are completely open. The back of the baffle would have dampening material to stop reflections, and the defector would be highly reflective and filled with sand. I'm hoping to build a mule when it gets a little warmer.

I thought about useing similar cabinets to your pictures for my B200's, but I don't know how they get away with no damping material behind the baffle. My biggest concern with useing those cabs with the SI is the 15" driver moves a lot more air than an 8" and I think it would really muddle the sound. I'm no even sure my idea will work.

Chris


Hey Chris,
I remember you Birthday order from you Dad-in-law... Diana and I though that was cool.

I like your idea and can only offer the following as this is a bit out of my area of experience..

Make that back wedge a nice curve. I you make "stops" at both side... you could flex a piece of thin 1/8" plywood into these and thus create a nice curve. Once glued it should be fairly strong.


You could also make half round braces that run horizontal. If you preplan this well you could use the driver cutouts, cut in half to form these 1/2 round braces... Back filling the entire thing with sand will be very heavy and maybe not needed? I would cover this in felt and maybe drop a sand bag or two into the cavity.
You are in essence then creating a poly cylindrical diffuser and should see good results.
We have a couple of examples in the builder gallery of similar projects.
Both builders reported very high satisfaction with their projects...
Good luck with yours.

Cheers
Darrel :D
PS You have a cool Dad-in-law.
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Re: Open Baffle "Cabinets"

Postby corloc » Mon Feb 11, 2008 2:52 pm

Slinco wrote:I think I'll give something like this a try at some point. One of the reasons I like the idea is because the front wall behind my speakers is mostly glass, with no curtains, and obviously HIGHLY reflective. I like the idea of deflecting the back wave out to the sides, or even up to the ceiling some way or another.

Chris, keep us posted if you give your idea a try.


That's a good reason to try to build them. You might try and build cardboard deflectors to see how them would effect the room. I did that for my B200' with decent success.

I will keep a post going, I really want to smell some sawdust. :)
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Re: Open Baffle "Cabinets"

Postby corloc » Mon Feb 11, 2008 10:58 pm

Darrel Hawthorne wrote: I remember you Birthday order from you Dad-in-law... Diana and I though that was cool.


Ya, My father-in-law is pretty cool. I knew I was going to get along with my in laws when I notice that Dad had the full collection of Monty Python on DVD. :D

Darrel Hawthorne wrote: I like your idea and can only offer the following as this is a bit out of my area of experience..

Make that back wedge a nice curve. I you make "stops" at both side... you could flex a piece of thin 1/8" plywood into these and thus create a nice curve. Once glued it should be fairly strong.

You could also make half round braces that run horizontal. If you preplan this well you could use the driver cutouts, cut in half to form these 1/2 round braces... Back filling the entire thing with sand will be very heavy and maybe not needed? I would cover this in felt and maybe drop a sand bag or two into the cavity.
You are in essence then creating a poly cylindrical diffuser and should see good results.
We have a couple of examples in the builder gallery of similar projects.
Both builders reported very high satisfaction with their projects...
Good luck with yours.

Cheers
Darrel :D
PS You have a cool Dad-in-law.
=D&gt;


Hmm, waste not want not. I will have to play with the dimensions a bit to use the half rounds, but for the mule I'm trying to spend very little to nothing for the build. Just useing stuff about the garage. So useing the cut out would be an advantage. As for the deflector, I was thinking that the wavelengths were big enough that I didn't need to have anything to curved. If I went with a half round deflector. I may have to find a way to have it visible. I think it would look cool. :D
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