Posted by Roy on January 25, 2003 at 04:00:35:
In Reply to: This should come from Dr. West. posted by Al Sekela on January 24, 2003 at 08:26:52:
I can add a little more information on this subject.
The thinner Mylar was introduced at the end of 1993. My old panels are 1994 vintage and upon inspection I can confirm that they have the thinner film. So that makes it 8+ years ago that the thinner film was introduced.
When my new panels were delivered one of them had a lack of energy in the center, this effected about 2/3rds of the panel area.
See: http://www.otlamp.com/slogforum/messages/395.html
I took measurements of this at the time for Roger West to see. When playing some white noise the edges of the panel had considerably more high frequency energy than the middle of the panel. This could be interpreted as reduced efficiency. The cause of that problem may be associated with what Joe S is experiencing.
Joe. Do you have a CD with White or Pink noise on it. If so please listen to the noise signature across the width of the panel. Does the entire panel have the same signature or do the sides have more high frequency energy. The effect that I had was not subtle, it was as if the sides had twice as much high frequency noise as the middle
Here is a link to the curves I took that show the uneven response.
Roy
