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12/19/18 at 13:55:29 


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What do you guys think about this? (Read 2411 times)
Ex Member

What do you guys think about this?
10/15/06 at 01:18:59
OKay here goes.

This idea came about when I was mathmatically experimenting with the technology around the Graham HOlliman project I was doing. (gave it up cause I don't want to hurt someone and got tired of feeling sick, unbalanced, and headachy.)

Here is my idea.  I was getting excietd about using a PR in a Wo32 because one of the major side effects of using a PR is that if the PR is not twice as large as the driver driving it then it tends to want to tear itself apart doing twice the XmaX of the driver.  There is a possibility that a PR CAN indeed be used in a WO 32 and even be smaller than the driver by a 1:0.8 diameter ratio. (driver being 1 and PR being 0.8 the diameter)

The reason for this is the close proximity of the adjacent wall of the horn that the PR would be radiating into.  The advantages of a PR vs. Port are:

1: A PR can be finely tuned using such a simple device as a sticker that adds the weight of the sticker and to really FINE tune it the wieght of the adhesive.   Roll Eyes
2: A PR often moves in phase to the driver. (contrary to what most people would think.) ???
3: A PR reduces the springiness (SP?) of the air spring behind the driver. Smiley
4: A PR does not whistle, make noises out of band, unload the driver at frequencies below it's tuning.

Disadvantages are:
1: the biggest disadvantage (or advantage) of a PR is that it has a really steep cutoff rate.  The steepest of any loading at 36db per octave!
2: Cost. Unless you happen to have a blown driver sitting around or make one yourself using a MDF ring and a driver surround..
3: The "normal" size requirement is twice the size of the cone of the driver driving it.

So with that in mind, how about a WO32 that has a driver in the top/side of the cabinet and a PR 20% smaller than the driver where the driver would normally be?  This would allow you to use a pair of thermally blown 10s with the magnets removed and some weight added behind the dust cap for the PRs.  Then you could run a pair of 12s, or smaller, drivers on the outside of the cabinet looking all purty.  8)

Anyone know of any online PR cabinet calculators that would use the T/S parameters of the driver and give feedback with a frequency responce graph or table using different weights and daimeter?

Thanks for any input.
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