Open Baffles with small exit Penetrations

Hello all,

Thinking of putting a little OB project together and cant help but ask regarding exit holes - see attached a la Emerald Physics - I would believe that the smaller exit is designed to "front load" the driver - but is it advised?

I admit, I am one LAZY SOB, and I have a 6" Hole Saw, and I hate using my jigsaw, as it always ends up looking like Stevie Wonder used it.

Application (with DCX2496) - pair of Eminence Alpha 15A mounted to front of 1-1/2" thick Baffle, or to backside with 6" exit hole...

Yes, No, or Hell No?

Go!
 

Attachments

  • cx.jpg
    cx.jpg
    169.3 KB · Views: 333
Last edited:
I don't think it has much to do with loading. I think the smaller opening is used to enhance the directivity (making it wider). This is based on zero simulation, just seat-of-the-pants conjecture. So I may be completely wrong.
 
Some loading; I don't have time to check the details but probably a compression ratio of something like 2:1. That will have some directivity impact too of course, although being a circular hole rather than any more dramatic change a la a BBC type slot or one of JBL's more complex shapes, it's unlikely to be vast, especially at the wavelengths I assume the drivers are operating over.
 
I tried this once. Two 12 inch and a full range. I found on larger excursions the foam surround of the drive unit would flap against the panel. They were rear mounted types. If I were to do it again I would use two panels glued together one with full holes cut with a jigsaw with the drivers rear mounted. The rear mounted driver will hide the cut and another panel with the hole drilled on the front which will hide the jigsaw hole from the front. This will give the drivers room for excursion.
 

Attachments

  • Flat panel speakers.jpg
    Flat panel speakers.jpg
    788.7 KB · Views: 197
Last edited:
Hello all,

Thinking of putting a little OB project together and cant help but ask regarding exit holes - see attached a la Emerald Physics - I would believe that the smaller exit is designed to "front load" the driver - but is it advised?

I admit, I am one LAZY SOB, and I have a 6" Hole Saw, and I hate using my jigsaw, as it always ends up looking like Stevie Wonder used it.

Application (with DCX2496) - pair of Eminence Alpha 15A mounted to front of 1-1/2" thick Baffle, or to backside with 6" exit hole...

Yes, No, or Hell No?

Go!

One other benefit, besides what others already mentioned, is that baffle is much stiffer with smaller opening. In comparison to what Jamo did for instance.
Careful with membrane hitting that front baffle, just like Stal observed. I would use some ring to space it a little.
Rather than one hole, you can experiment with few strategically spaced, and report back, since I am lazy too 🙂
 
Hello all,

Thinking of putting a little OB project together and cant help but ask regarding exit holes - see attached a la Emerald Physics - I would believe that the smaller exit is designed to "front load" the driver - but is it advised?

I admit, I am one LAZY SOB, and I have a 6" Hole Saw, and I hate using my jigsaw, as it always ends up looking like Stevie Wonder used it.

Application (with DCX2496) - pair of Eminence Alpha 15A mounted to front of 1-1/2" thick Baffle, or to backside with 6" exit hole...

Yes, No, or Hell No?

Go!
Instead of LAZY SOB it could become a LAZY SLOB (Slot Loaded Open Baffle) the lazy bit being a hole instead of a slot.
 
Aha! Multiple sound holes like a Ovation Guitar?

While that would look cool, donno how it would sound... always wondered why they did that, but they sounds great with and without pickups!
 

Attachments

  • ovation_shallow_bowl_ce_868_1.jpg
    ovation_shallow_bowl_ce_868_1.jpg
    176.5 KB · Views: 150
Last edited: