OB's ... Is a single-piece front superior to a folding design?

[Brisso57]

I'm thinking about my next OB FR single driver project.

In the interests of WAF, I find myself considering using some "piano" hinge to make the front baffle a 3-piece affair, with either side being able to be folded back ... solely to facilitate storage in the living room when not being listened to.

I'm thinking 1700mm baffle height or thereabouts.

My question: Will such a design noticeably affect the sound quality?

Comments?

Doug

[Vix]

In my experience Open baffle sounds best with a single piece. If there's a fold, OB looses some if its midrange "magic". Note that I've only tried this in the relatively small room (too small for the OB - 4x4 m). Maybe in the bigger rooms the effect is not so pronounced...

Regards,

Vix

[Nelson Pass]

A flat baffle avoids much of the diffraction effect at the edges because you get
good front-to-back cancellation. It does indeed sound better.

[Brisso57]

Nelson, Vix,

I failed to make my idea clear.
It is my intention to have a baffle that is flat (& vertical - or almost) when in use, but may have the LH and RH 1/3(say) foldable, with a continuous hinge running full height.

My concern centres around:
1. The effect on resonance ... of 3 coupled pieces; and
2. The effect of discontinuities in the baffle.

Your thoughts now ?

cheers

Doug

[MJK]

Originally posted by Brisso57
My concern centres around:
1. The effect on resonance ... of 3 coupled pieces; and
2. The effect of discontinuities in the baffle.

I think that splitting the baffle into thirds would push the first resonant frequency of the panels higher compared to one large sheet. I think that would be a significant advantage. Instead of one long piano hinge, you might consider two smaller local hinges with a soft foam weather strip to be compressed in the gap when the wings are rotated into listening position, it would provide a little damping and help prevent excitation of the side panels.

I would not worry about a small discontinuity in the baffle at the seams. it will be a minor impact compared to the baffle edges. Just to be safe you might consider having the side panels different widths so that the two seams are at different distances from the driver, or you could offset the driver to get the same effect.

I think your idea is good. It will not compromise performance and it will maximize acceptance by she who rules the roost.

[Brisso57]

Originally posted by MJK


I think that splitting the baffle into thirds would push the first resonant frequency of the panels higher compared to one large sheet. I think that would be a significant advantage. Instead of one long piano hinge, you might consider two smaller local hinges with a soft foam weather strip to be compressed in the gap when the wings are rotated into listening position, it would provide a little damping and help prevent excitation of the side panels.

I would not worry about a small discontinuity in the baffle at the seams. it will be a minor impact compared to the baffle edges. Just to be safe you might consider having the side panels different widths so that the two seams are at different distances from the driver, or you could offset the driver to get the same effect.

I think your idea is good. It will not compromise performance and it will maximize acceptance by she who rules the roost.

Hi Martin,

Thanks for your encouragement.
Now to reveal the drivers ... (cue drum roll) ... vintage Peak 10CX50's.

I have a pair of 8CX50's and just love the sound in OB. I'm hoping the 10's have everything the 8's do, plus a bit more deep bass. (I also intend to mount these higher off the floor.)

I'll post a photo or two when there is something to show.

cheers

Doug

[Nelson Pass]

Jon Ver Halen of www.Lowther-America.com points me to the
following link:

http://www.troelsgravesen.dk/OBS.htm

[Brisso57]

Thanks Nelson. I hadn't seen that reference previously. Some very good info.
I'll be mounting my driver higher than 700mm though.

cheers

Doug