MANY THANKS WAYNE. I am going to study about the Quarter Wavelength Loudspeaker Design next as a new topic for the summer. There seems to be a lot of people exploring this issue and model speaker. It's amazing what the ressonances can do. They can amplify the sound many times up. I have a kitchen (4.3x6.2x8.5ftHeight) with room modes at 60/90/130Hz and it's crazy how it develops the sound from engines like the bus at the bus stop and some boats running close to the beach. I found this in the living room and it generates from the kitchen (and chimney). Just amazing, it's many times stronger than going to the window. Best Regards.