BillFitzmaurice.info

To do or not with live sound drivers.
Here's a link.
http://www.enjoythemusic.com/diy/0310/m ... f85ken.htm
Lets see what Bill says??

Mkulu wrote:To do or not with live sound drivers.

Don't bother, with any drivers. People who do this stuff tend not to have any clue what they're doing. People who sell this stuff are snake oil merchants. Case in point, what's referred to as a 'phase plug' in the article isn't a phase plug. It's a pole piece extension. The change in the measured results had nothing to do with the addition of the pole piece extension, everything to do with the removal of the dust cap. Also, the measurement shown isn't response, it's impedance. The claim that 'there is a major improvement in the smoothness of this trace. This means less stored energy, and smoother overall driver behavior' is just plain hooey.

Bill Fitzmaurice wrote:

Mkulu wrote:To do or not with live sound drivers.

Don't bother, with any drivers. People who do this stuff tend not to have any clue what they're doing. People who sell this stuff are snake oil merchants. Case in point, what's referred to as a 'phase plug' in the article isn't a phase plug. It's a pole piece extension. The change in the measured results had nothing to do with the addition of the pole piece extension, everything to do with the removal of the dust cap. Also, the measurement shown isn't response, it's impedance. The claim that 'there is a major improvement in the smoothness of this trace. This means less stored energy, and smoother overall driver behavior' is just plain hooey.

Thanks Bill,
My opinion in line with yours, but a lot less technical.

I have made one of my own heatsink, Just as PI speakers sells them.


Have yet to use it, don't have access to a lathe anymore. I still have one laying about though. Was cool to make when the shop was slow.



It's said to really help in rear chambers that are cramped. Bill's designs with the access door not perpendicular to the driver won't allow it - and these are all of the designs I use! Have yet to need one, as I voltage limit far below what the limit is.

There's another way to approach the issue: Don't make the rear chamber too cramped.
A bit of history: When Danley designed the LAB Horn someone fouled up and the published design rear chamber was made much smaller than the spec called for. That led to using aluminum access covers to shed heat from the chamber. The 12 Pi sub heat sink improved upon the concept, but if you make the chamber the right size to begin with it's not necessary.