Anyone with comp driver modification experience?

[moray james]

I have an old set of Peavey 22A compression drivers. This is a solid and well built/designed wide band driver by the look and sound of it. The driver has a half sphere plastic phase plug which has a number of holes which focus to the throat, the plug sits right under the diaphragm. The holes are cleanly drilled. I was wondering if breaking the edges of these holes making a small chamfer would help or if it would make matters worse? Thanks you your comments and suggestions. Best regards Moray James.

[Deang]

Just curious -- what do you hope to gain by doing this?

[moray james]

I don't have any experience with comp drivers but I figured that the sharp edges of the holes in the phase plug were likely not doing much for smooth non turbulent air flow on either side of the plug. Given the design that often goes into these products I thought it best to ask if anyone could tell me it my idea was a good idea or a bad one because the sharp edged on the holes served a purpose. I would not be hard to chamfer the holes but I think asking is the wise thing to do first. Thanks Dean be well. Best regards Moray James.

[Deang]

It just doesn't seem likely that it would make any kind of an audible difference.

How are you doing?

[moray james]

I imagine that it might make things worse not better I figure the smart guys who design these things would have tried this but that's not always the case so i wondered. I do think that it would however make an audible difference the question for me is for better or for worse? By way of example I have been experimenting with damping my horns which are in this cas the Peavey CH-1's. I have been playing with mouth termination reflections and it is mind blowing what differences you can affest with small amounts of damping in the mouth of a horn. None of my available Heritage Legend or Epic horns come close to the CH-1's. I expect that I would have to make the jump to the much larger K402 to better the CH-1 horn. I would bet a nickle that the K402 would also benefit from damping in the mouth as well. I get the impression that to simply design mouth reflections away is not in any way a simple tasl. Perhaps Roy D. could comment on this topic? (if he reads this). i have been bugginga friend with K402's to slap on some damping and give me his impressions. Anybody with a set of K402's up for some simplefast experiments? Let me know I will give you the details. Thanks for your interest Dean. Best regards Moray James.

[djk]

The early salt-shaker phase plugs are OK.

RCA used them, Tannoy used them, JBL used them (2415).

Don't mess with them.

[moray james]

That seems to be good advice which I will take. If these had been made of metal rather than plastic they would have provided additional heat sinking to the unit. Dennis do you have any idea as to how the diametre of the hole size in the shaker style phase plugs were chosen? For example how would cutting the diameter of the holes in half and then increasing the number of holes so as to maintain the same original open area, how would that impact the response? I am still curious to get an idea of the why in general terms. Thanks for the advice. Best regards moray James.