A great alternative that is available in most parts of Canada is CertainTeed. The best in their line is CB300 which is identical to OC703 in every manner, including acoustically. The published coefficients for CB300 are in effect the same as OC703, and this material will be MUCH cheaper than the Sonopan insulation. Where are you located exactly? I may be able to point you to a local dealer of this material.

Cheers,

Joel DuBay www.readyacoustics.com