[ntell411]

Hello everyone, my name is Nico and I am a long time audiophile nearing retirement and trying my luck-lol at building my first open baffle speaker using large woofer(s) and a full range driver. Specifically, I am considering using 2 Goldwood 18 inch woofers mounted on a flat baffle FACE TO FACE wired in parallel (4 ohm load) and IN PHASE with each other (move forward and back together as one) with the goal of reducing the overall system size and increasing the quality AND quantity of bass output. I know this is a variation of SLOB arrangement. It seems like the trapped air between the woofers would act as a stiffer spring thereby increasing sensitivity, qts and ultimately bass output.
P.S. I re-posted my question here for more comments from the open baffle community.
OOPS: wired OUT of phase like isobaric; cones move in same direction

[JohnR]

FACE TO FACE wired in parallel (4 ohm load) and IN PHASE with each other (move forward and back together as one)

Electrically, they are wired out of phase, correct? If so, that would be like an isobaric OB. SPL won't increase, efficiency is half, whether sound quality improves you would have to see.

If they are wired in phase (cones are moving physically in opposite directions when facing each other) then you have a monopole.

[FullRangeMan]

Nearfield Acoustics PipeDreams two 18'' per cylinder were out of phase connected.

[matevana]

If the woofers were in an enclosure, you would benefit from isobaric loading in the form of a smaller box. However I don't see any advantage in open baffle. Please let us know what you find.

[ntell411]

Thank you for the correction of "in phase versus out of phase". I edited my original post to reflect that. I will do some testing on an open baffle with this arrangement and let you know.
 
Almost forgot the most important reason I was considering this arrangement: the CTC (center to center) spacing between the woofers and full range driver would be 9+6=15 inches allowing a crossover at 200-225 hz without any problems of comb filtering or other frequency aberrations.

[hallcon83]

-  Hello , I found your posts in the thread " Unique Woofer Arrangement for Open Baffle Bass" , where you were talking about your Ideas for using the Goldwood 18 inch drivers mounted on a flat baffle Face to Face - in an isobaric design, and enjoyed reading thru it ..... what is really funny is I have been thinking about a similar kind of design for about a year and am about to get started too. It was really strange reading thru it though - I felt like I was reading one of my own posts that I don't remember writing - LOL .... 
-  I was wondering how far you had gotten with you design/speaker.... and wanted to maybe exchange some Ideas with you. I found some interesting websites talking about the Idea and wondered if you had seen them.  Thank you,

Best Regards,
Dean

[hallcon83]

-  Sorry if the above reply is worded kind of strange, I tried sending it as a Personal message , but the website said for some reason you couldn't receive Personal messages, so  just posted it here and am hoping you stop by some time , thank you , Dean