12 inch woofer dispersion pattern

[krzys]

Guys measuring spatial dispersion of a woofer is very hard task in home environment . Is there any any mathematical way or even a rule of thumb to know the dispersion pattern of a woofer vs the frequency? Specifically I'm looking for information for a 12 inch woofer like the Altec 414.
Chris

[timc]

Geddes has stated that generally dispersion is at 60 degrees at 800-1000Hz. (IIRC)

Ofc there are exeptions.

[Robh3606]

Here's what a 12" 2206 looks like in a small box. The Sym agrees with Earls statement.

Rob

[timc]

A sidequestion about measuring polar pattern.

Do you draw a 1m circle from the woofercone or a 1m circle from the speakers center (center of the cabinet)?


If you use the cone as reference you risk getting very close to the back wall.

[4313B]

Guys measuring spatial dispersion of a woofer is very hard task in home environment .

Yes, a really big room and one of these contraptions helps. The black square has a 360 degree dial inside it.

[DanTheMan]

I found this floating about on the web somewhere. It has worked well for me.