my new 604 cabinets I'm building.

[voice of the theater]

Ok this morning I decided to try some backs so I gathered up my scrap wood and put backs on all but 1 small 4 x 15 area in the bottom part of the back. It sounded just like the heathkits, boomy and the lows were way loud and you could hardly hear voices so I thought about it and decided to try this (the picture)once. They sound very nice and level and open now. Don't ask me why they just do. Those are 4 openings each 1 3/8 by 15 totaling 82.5 sqIn.
I shot a little bit of Avatar with them like this, will post up as soon as I get it on you tube.

Finding the tuning/port size that best suits your drivers, cabinets, and room acoustics can often times require an empirical/trial and error approach. Sounds like you found a great tuning/port size for your speakers/room acoustics--enjoy!!!!

Just an update, and an opportunity to kick my own ass on national internetvision. ok, so I've been plagued by this "stupid one channel doesn't sound as good as the other one" problem for about 4 months now...... so I go to the back of the receiver and start turning the rca plugs from the Nady while they're plugged in and then I see the ones from the dvd player and I'm like no way!!!! I spin one boom the channel is totally back to life.... Story of my life.....

Hey, at least you finally found the problem (yourself) and didn't have to hire an electrician or an exorcist!