4311 Port Tubes

[rek50]

I recently aquired a pair of 4311 PT's. In the component exploded view (Thanks Bo) there is a "Donut" shown on the end of the tube. What is it? Does it do anything for the sound?

[boputnam]

I believe that is a wrap of fiberglass. It's a good idea to wrap the entire duct thusly - adds back virtual volume for some of that consumed by the duct.

A simple roll of plumber's pipe / duct wrap will do - couple inches wide, and secure with some tape.

[bob newton]

Bo is absolutly correct. I have a pr of 4311's less drivers, so I looked and YEPPERS, thats whats there. Insulation on the top half of the 90 degree elbow.

With paper tape , one turn around the middle to hold the insulation there.

[rek50]

Thanks! As always, I'm VERY impressed with all the Knowledge/Help on this site. There's SO many aspects to Hi-Fi sound. I've been reading here for over a year, trying to grasp some of the "Fine" details.