Hey Danny,
This may seem like a dumb question 
but, when you suggest keeping most of your ported designs at least 3 feet out from walls, is that form the rear of the cabinet because of the location of the port or is it from the front baffle? Also, is it the same for OB designs?
Thanks,
Larry
Actually the ported designs can be placed closer to the wall than that. As the speakers get closer to the wall then the lower bass output will pick up some. And the port output (if in the rear) will create some gain. If the gain from the port output causes a bass peak then the port length can be increased to lower the tuning and shift the gain from the port down into a region that was a little lower in output.
Open baffle speakers are a different story. You are dealing with a wall reflection and the time arrival of the reflection. You want to create a long enough delay (arrival of the reflection) so that your ear perceives it as a delay and not a smear of the direct output. So three feet or more is the rule of thumb.
