thanks
-akhilesh

I think that the position of the driver, the port, and fiber fill for damping can be used to minimize the impact of standing waves on the back surface of the driver. A standing wave with a pressure maximum on the back of the driver's cone will tend to reduce the cone motion and cause a null in the driver's SPL response. Again, look at Figure 6 in the ML TQWT article.

Martin

http://www.trapagon.com/Audio/Products/body_products.html

http://www.crystalaudiovideo.com/cmptechnology.asp

http://www.gspr.com/canton/ref2.html

http://www.humanspeakers.com/diy/cabinets.htm

And many more. The conventional wisom seems to be that parallel walls encourage standing waves. I haven't tried to analyze if this should be true or not. The conventional wisdom is probably based on empirical experience of different builders.

What do you think? I am trempted to build my future BR cabinets with trapezoidal shapes.
thanks
-akhilesh

I looked at each of the websites you reference and they all say that non-parallel walls will not support standing waves. I think this is great marketing lingo, I don't believe that standing waves in an enclosure can be eliminated. There will always be resonances and mode shapes in any volume. Maybe the non-paralel walled enclosures will have "weaker" modes as seen from the back of the driver cone compared to the nice rectangular enclosures, I don't really know.

The location of the driver and port on the front baffle can also be used to mitigate the number of standing waves excited. Stuffing also does a great job of attenuation. Having built one tall thin trapazoidal enclosure, I am not looking to tring and odd shape again. Nice and square is much easier.

Martin