Wayne; Thanks Much for the prompt reply and I will tell you why I asked and keep it brief. After completing my pi 4's about 4 weeks ago(I built them exactly to your specs) I have been listening and I have slowly grown to enjoy them beyond my expectations. Musicality, lively, tone etc. Now I would like to build my altec valencia components into a pi configured box. On the altec site they seem to think all the woofers should be measured before designing the bass bin claiming that altec data is unreliable. Since this project will be expensive I am posting this under this thread hoping that some might have either experience or opinion concerning designing around the published specs or paying for testing. I have my pi sticker on the 4's but is it apropriate to use if the altec drivers are used?( I bought the 4's from you).