Posted by Dr Mark Carter [ 208.107.219.50 ] on December 19, 2006 at 07:21:32:

In Reply to: Need Help Tuning Vintage Electro Voice Cabinets. posted by Ed White on December 14, 2006 at 05:21:12:

Dear Ed,
I did find the parameters for your driver. I have done some calculation for the size box you have. It would help me to know whether your dimensions are internal or external, and what the thickness of the walls are. This box does not need a vent tube. I assumed the cabinet had 3/4 inch walls and that your dimensions were external. If those assumptions are not correct, then these numbers need recalculating. A whole 4.5 X 4.5 inches gives optimal tuning and will give you an F3 of 50 HZ.
You could also make this a closed box. You would need heavy fill in this case. The ported enclosure needs very light fill by the way. The F3 of the closed box would be 78Hz. However the roll off of the vented box is 24db per octave and the closed is 12db per octave. It ends up being a wash. However the closed box design can be equalized without adding greatly to bass distrorion. Therefore with EQ you would get more and deeper bass from the closed box. A vented box does not take to bass equalization well at all.
The driver is efficient and has good power handlng and watts are cheap. I would try the closed box with heavy fill and add an Eq of plus 12db per octave starting at 80 Hz. In other words, +12 db at 40 Hz and +24 db at 20 Hz. I would brace the cabinet, as well as add fill. I think you might be quite surprised at the sound of the equalized closed box solution.
If you are interested in pursuing this let me have more accuarate dimensions.
Regards, Mark.

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