[lokie]

But your bracing could be greatly improved by using window framing type design.  (Run bracing in a box shape lining the inside of the cabinet walls at intervals equal to the the cabinet width/depth and perhaps adding cross bracing or a sheet of plywood with a large hole cut out of it at midpoints of the box shapes.)

Pictures, Pictures Please!

BTW, I crossover at 2khz. My speakers aren't perfect but I hear nothing but goodness around this range.

[SteveRB]

Uh? Tell that to Tannoy, Shindo, Altec, Western Electric and.....

In my DIY 2 way, I am putting on various size back panels to experiment w port sizes. The differences aren't much. Even compared to a sealed cabinet. In fact, I have been experimenting w one speaker sealed and the other (see picture) w a port. I can barley hear the difference and the imaging is rock solid.

In contrast, taking out the internal dampening (3/4" wool covering all the walls) and replacing w bracing was a huge improvement. Now, I only have dampening on the back panel. Still tinkering here.








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Very nice. What are the components you are using?

[SteveRB]

See below for impedance plots of enclosure with two 4" diameter x 3.75" long ports. System tuned to 34Hz. This is as close as I can get to matching impedance peaks. The in-room SPL curve closely match the curve when using one 4" opening.

The math holds: doubled the port area and quadrupled the port length.

The sound feels a little over dampened right now. I'll likely pull out some of the fibreglass next week.

[lokie]

Very nice. What are the components you are using?

Altec 802B in a 32B Horn and a 15" Jensen P15ll woofer.

SteveRb- I wish I had your measuring skills. Cool plots!

[SteveRB]

Altec 802B in a 32B Horn and a 15" Jensen P15ll woofer.

SteveRb- I wish I had your measuring skills. Cool plots!

http://audiojudgement.com/loudspeaker-impedance-measurement/

step by step measurement instructions WITH spreadsheet that crates the plot.

[lokie]

http://audiojudgement.com/loudspeaker-impedance-measurement/

step by step measurement instructions WITH spreadsheet that crates the plot.

Thanks-  but if I took the measurements, I still wouldn't understand it. The first sentence in the article stopped me in my tracks.

"Making a loudspeaker impedance measurement is not a as easy as you might think."

I'm better w sawdust and listening than charts and graphs. I know you really need both but I only have so much time, so I do what I enjoy.