Shape of OB Baffles

[quickshift]

I've made some OB speakers out of cardboard as an experiment and like the sound enough to want to try to make something that doesn't use duct tape as an important structural component

However, I can't find any type of guide as to the shape of the baffles. I've read about flat baffles, W Baffles, U baffles and H baffles but can't find anything to help me determine the shape I should be using.

What I want to do is make the baffles the shape of the attached diagram but haven't seen any that look like that so I don't know if it's a good idea or not.

Is there any info out there I can be pointed to which explains it or would someone please explain how to select the right baffle shape?

 

[quickshift]

Anyone?

Is it a silly question?

 

[pdan]

Too much thinking kills creativity.

Just do it .

Then you'll know if its "right" or "wrong".





Cilla

 

[quickshift]

I like your way of thinking

I'm guessing there advantages and disadvantages or rather characteristics (?) to each different type of OB baffle shape so was looking for some info before buying in the materials.

If it really is a case of try it and see as far as OB goes, that's fine, I'll go ahead and see if it works or not

Maybe that's why I couldn't find any information about different baffle types on the internet.

 

[edjosh23]

I would recommend downloading the baffle diffraction simulator from here .

About your baffle: Beside driver placement and the actual shape of the baffle, edge diffraction is an important factor. To reduce this large roundovers are recommended, the larger the better. So if you can buy 1.5" roundovers and add those that is great. I think that the roundovers need to be on the sides, not on the front. I believe that by adding angles to the front will increase diffraction.

Josh

 

[quickshift]

Thanks edjosh23, I think you're right about that shape I'd like to use increasing diffraction. I'll measure a version with, and without the cylinders on the ends. Thinking about it, I guess I'll get a bump in the FR that corresponds with the distance between the cylinders.

Thanks for the link, I was using The Edge as a simulator as it has a setting for OB. The BDS app looks useful though.

 

[sdclc126]

I've read a lot in favor of large roundovers for OB and conventional closed boxes. I've seen pics of Linkwitz's Phoenix with large "wing" roundovers - several inches in fact. There was supposed to have been significant improvement. Don't have the pics though. I think you should try it this way.

 

[Hatti]

Hi, im thinking, that it´s very important, to have the right shape of the OB.

I built this one...: http://www.diyaudio.com/forums/showthread.php?s=&threadid=103043

...with a little help from "edge" simulation software.
this software only can simulate a plan baffle.

greatings, Hatti

 

[Nanook]

why not try what I did...

and make the Quad ESL sized baffles? Response programs suggest they shouldn't , but do.
31.5" X 35" wide, driver, centred , 13.5" up from the floor, 10 degree slant backwards.

 

[Rudolf]

quickshift,
have a look at this post and the preceding and following 60 posts in the Ariel thread to get a better understanding of baffle edge diffraction.
Lynn Olsons proposal of "lossy" baffle edges seems much more promising than what you suggest.

Rudolf

 

[quickshift]

Hatti, interesting. Thank you. I but they are a talking point

Nanook, having just moved house, I've got more than enough cardboard to try that and do some measurements. it has to be worth a go, thanks.

Rudolf, thanks for the link. Looks like I have some reading and lots of understanding to do! Your site looks very informative too so I'll run through that this morning.

Cheers all