Open Baffle Design Help

Hi,

I am looking at building some open baffle speakers with the Lii audio F-15s and am trying to decide on baffle dimensions. I will be listening quite nearfield and am limited on space between the sidewalls, although have plenty above and behind me. so I was thinking of a baffle size of 70x75x4cm. Ideally this would be smaller, something like 60x65x4cm.

Would there be an appreciable difference in bass response between these two baffle sizes?
Another option would be to go something like the much larger baffle here, but again not sure how much of a gain this would be http://jelabsarch.blogspot.com/2012/06/open-baffle.html?m=1

Also, is it an issue to mount the drivers centred and the baffle is almost square. Is this of any detriment, is it better that they are off centre? Would that make an appreciable difference nearfield?

I plan to add a sub later on, and don't need thunderous bass. In this setup I'll mainly be listening to jazz, soul etc.

Thanks in advance for your help.
Quick mockup attached of the various sizes in relation to my listening space for comparison
 

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Extending the height will strengthen the bass output as well as allowing you to position the full range driver nearer to the ear level of a seated listener.

Bass is improved greatly the closer the driver is to the floor due to room effects it's similar to extending the baffle size.
But yeah, baffle size and shape is a tricky thing and results to the sound quality overall can be unintuitive.
Bigger is not always better, or at least diminishing returns
I'd suggest listening to the many over-air recordings that Decware made of these baffles on their Youtube page.
 
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Yes, but brings with it the problem of floor reflections and having to listen to the full range driver off axis.

Compromises, compromises! 🙂

That's what rugs are for - and nobody listens standing up.
Any issues with off axis can usually be dealt with by adjusting toe-in and tilt back of the speakers as you can see is done in the video above.
In general yeah, with OB's you have to pay more attention to room treatment and speaker placement but that's regardless of baffle size.
 
Btw, IRL the baffle size affect on the overall sound quality is unintuitive.
Yes you will get higher bass output and more extension with a bigger baffle but other aspects of the sound - eg. soundstage/imaging - can suffer.
An example in that small barrel shaped baffle with 8" driver in the video above. The guy (Randy) who invented, or discovered, that size and "barrel" shape tried many different baffle shapes and sizes before settling on that one that sounded best overall for that particular driver - the Wild Burro Betsy 8".
 
I see I completely misinterpreted what I was seeing higher up the page. I thought the baffle was for a larger driver and I was chasing the 8” Bettsy baffle dimensions. Thank you for your efforts though! Sorry for not being clear enough.
yeah there are two "barrel' shaped baffles, the small one "Betsy" is for an 8" driver.
The other one that Decware sells - I think - is for the Lii Audio F15 fifteen inch driver.
Dimensions are in the spec sheet below.
 

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Here is the prelim plans for the Decware OB for the Lii F15 driver you can see it's nearly 30" wide at it's widest in the middle of the barrel shape, so twice the size of the driver. Btw, you can buy the final plans on the Decware site for $30 here, but I think these prelim ones I downloaded off the Decware publicly available forum is sufficient. Just so everyone knows I'm not giving away anything they are selling.


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