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Baffled by Baffles.... [message #21964]

Fri, 13 June 2008 12:02

gfederys
Messages: 46
Registered: May 2009

Baron

Good Morning, Are there any OB experts lurking about? I've looked up and read all I could, but still haven't been able to answer my question. I thought I had read @ one point, somewhere, that it's advantageous to mount the main driver off-center of the baffle instead of dead in the middle. What I can't seem to remember, or find, is whether you want more baffle between the left and right speakers, or more baffle to the outside of each speaker, or was this just in a pipe dream somewhere, and you want them mounted dead in the center afterall? All constructive comments, ctiticisms, ideas, discussions, and direction are welcome. Thanx to all participants in advance.

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Re: Baffled by Baffles.... [message #21965 is a reply to message #21964]

Fri, 13 June 2008 16:36

Gerry Co
Messages: 1
Registered: May 2009

Esquire

Hi gfederys,

The way I understand it is you want to breakup the baffle step transition. It is even more imporatnt on an OB speaker than a box speaker because OB speakers don't just transfer halfspace to wholespace but they also transfer from constructive to destructive wavefront operation.

That's my penny. Add another for 2 cents worth.

Gerry

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Re: Baffled by Baffles.... [message #21966 is a reply to message #21964]

Sat, 14 June 2008 09:28

Martin
Messages: 220
Registered: May 2009

Master

As long as you are talking about a rectangular baffle (not square or circular) I don't think it makes that big of a difference. The location of the driver, offset or centered, will impact the ripple above the hump in the baffle's response. Compared to other anomolies such as the room, the crossover, and the driver's natural non-flat peaks and dips I think these ripples are in the mud. If you do bias your drivers towards one edge of your OB, and build a mirror image set, you can always swap left for right and try it both ways. Use the positons that sound best. Don't worry the small stuff, worry the big hitters in your OB design like relative driver efficiencies and woofer Qts.

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Re: Baffled by Baffles.... [message #21968 is a reply to message #21966]

Mon, 16 June 2008 10:28

gfederys
Messages: 46
Registered: May 2009

Baron

Thanx Martin, I've taken those things into consideration. I also am going to ad a tweeter because the main driver needs a bit of high end "help". The tweeters were going to be be placed @ a 45 degree angle to the main driver towards the center, therefore the question about where to put the most baffle, inside or out. I didn't thoroughly explain what I was contemplating doing.

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Re: Baffled by Baffles.... [message #21969 is a reply to message #21968]

Mon, 16 June 2008 10:48

Martin
Messages: 220
Registered: May 2009

Master

"The tweeters were going to be be placed @ a 45 degree angle to the main driver towards the center ...."

Why would you add this complexity? If the tweeter is firing forward then the design is a little more flexible with respect to placement. I guess I don't see the advantage to firing the tweeter at some angle and then listening off axis.

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Re: Baffled by Baffles.... [message #21970 is a reply to message #21969]

Mon, 16 June 2008 11:14

gfederys
Messages: 46
Registered: May 2009

Baron

I'm sorry, the tweeter WILL be firing forward, installed flat on the baffle surface. BUT, instead of being directly ABOVE the primary driver, it'll be about 2 o'clock in relation to the primary driver on one baffle and 11 o'clock in relation to the primary driver on the other baffle. I guess this is becoming a case of one picture being worth a thousand words.

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Re: Baffled by Baffles.... [message #21971 is a reply to message #21970]

Mon, 16 June 2008 12:06

Martin
Messages: 220
Registered: May 2009

Master

OK, I think I understand the geometry. Why do you want to use this placement of the tweeters relative to the mid/full range drivers? What is it buying you in performance? If they were mounted vertically then you could offset both drivers and still have the flexibility to swap channels. I am not trying to give you a hard time, I am just curious what is driving you towards these design decisions. Maybe it is as simple as looks which is fine.

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Re: Baffled by Baffles.... [message #21972 is a reply to message #21971]

Mon, 16 June 2008 12:35

gfederys
Messages: 46
Registered: May 2009

Baron

I don't perceive you're trying to give me a hard time and appreciate your replies. I wish I was better @ explaining so I wasn't wasting YOUR time. Since way back when, I always heard moving the tweeters slightly toward center improved the imaging. Whether this is true or an old MFG.'s tale, I'm not sure. I've been doing some preliminary OB testing on a pair of 18.5 X 18.5 baffles, mounted on speaker stands, so they're about 35" off of the floor. I run a small, powered sub/woofer to augment the low end. Currently the tweeters are mounted on some some small luan pieces on the baffle sides, since I was "hunting" for a tweeter to use. This allowed for quick switching and testing. I like the sound, and want to make some permanent, slightly larger baffles. I'm trying to see, (hear), if there are some ways to tweak these even more, without creating huge, floor standing baffles in the living room. That's why the original question about whether it's more advantageous to have more baffle on the inside or outside of the drivers. I guess another way to do it would be to mount them asymetrically, as you suggested, move them around to see if they sound better a certain way, then add the tweeters later.

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