"V"-Shaped Waves in a Tensioned Screen

I have had this 133" diagonal, HDTV format, Da-Lite Tensioned Contour Electrol screen with Cinema Vision fabric for about four months. I noticed that, lately, it has developed waves that run from the bottom corners towards the centre of the screen. These waves are quite serious at the corners when I lower the screen but tend to almost disappear after about a couple of hours of the screen being down.

Also, I noticed that the tensioning strings have never been really tensioned; when the screen is down, at times they are just taut (but not tight), other times they are totally slack, which suggests that the fabric might be shrinking and expanding.

My questions are:

1. Is it normal for a tensioned screen to develop such waves? I paid a big premium to have it tensioned because I thought tensioned screens were not prone to developing waves.

2. What should I do to eliminate the waves?

3. What would be the appropriate tension in the wires? How would one measure the tension in the strings to ensure it is correc? I have a feeling that, in my case, they might be too loose.

Thank you.

Michael

The manual does not mention anything about adjusting the tension. A CSR from Da-Lite told me that tension in the cables is not required as long as the sceen stais flat (???)

I was hoping to get some help here...

Thanks, Budwich, I will try to experiment as you suggested. My fear is that I don't tighten the strings too much and damage the screen (like snapping off the tabs from the screen material). I am surprised there are no guidelines for tensioning the strings.

At work we have a couple of Draper screens much smaller than mine and 4:3 format, and their strings are very, very tensioned. The strings of my Da-Lite screen are almost slack (factory adjusted).

Michael

Would you please post a link?...