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What would the best shape be for the plug? from what I understand the plug should take into account the dustcover shape to get max depth.

Monomer wrote:What would the best shape be for the plug? from what I understand the plug should take into account the dustcover shape to get max depth.

A dimple in the end would be best. It's not specified in the plans as most builders would have a difficult time incorporating it.

I found some 1 1/2" styrofoam at a nearby craft store. Would this be ok.
Also, if I could concave shape some foam to a closer depth to the speaker
what type of gain would I get for that effort ???

Thanks - RR

http://www.centauriaudio.com.au/diy/plugs.html


I was tinkering with the idea of waxing the driver up with sheetwax to make the proper offset while keeping the exact driver shape, and then popping off a mold.

it would render the exact shape of the cone/cap...

You and I sometimes think alike!

Rockboy wrote: Also, if I could concave shape some foam to a closer depth to the speaker
what type of gain would I get for that effort ???

Thanks - RR

You'd get a flatter response curve and higher sensitivity in the upper mids.

So, it sounds as if it would be worth the trouble to me.

David Sample wrote:So, it sounds as if it would be worth the trouble to me.

It's the same result as a smidge of EQ. I suspect most builders won't care about 1dB here and there, and that's what it would amount to.

Bill, not arguing here just asking: If it's only worth that little bit then why do compression drivers and most piezos that I've seen have phase plugs in them?

Shorter wavelengths. Much more amenable to what a phase plug does than midrange and bass. The wavelengths are just too long for much subtlety to have a big effect.

Thanks. Still, the upper end of the MR driver in the Omni cabs are getting to be pretty short wavelengths, aren't they?

David Sample wrote:why do compression drivers and most piezos that I've seen have phase plugs in them?

The same reason that the OTops do. What's being discussed here is the benefit of a dimple in the plug extension that will allow it to be maybe 3/8" deeper.

Well, it has me thinking.


If I could pop off this mold, I'd be happy to make some for other builders.


Would it make enough difference to warrant the effort? -over the plug in the plans.

Also, what would the proper spacing be? I assume it's a little bit past the one-way max excursion of the driver.

Monomer wrote:Well, it has me thinking.


If I could pop off this mold, I'd be happy to make some for other builders.


Would it make enough difference to warrant the effort? -over the plug in the plans.

Meh, I didn't even measure the throat filler in my jacks. I just kind of guesstimated that they were big enough to fill in the empty space and they get the job done. So it doesn't really have to be perfect or anything, and ESPECIALLY if you're EQing them, which is a must for any PA. I'm thinking a more complex (read: more expensive) crossover would make more of a difference, but still, they're fine like that.

Now, if we were building some crazy audiophile $1000 MTM's and powering them with some crazy $1000 tube amp, then I think the extra detail would be a must, but it's pro sound, we just want it loud