The simple trick is to hold the fabric to your mouth, and blow air through it, taking note of how much resistance you feel when you blow through it. (Note: You may want to order multiple samples if you and a colleague are both going to perform this test). The less resistance, the better the fabric will likely allow sound to pass through it to the sound absorbing material that will be behind the fabric.

Of course, the best route is to have the fabric tested, or choose from our collection of 50+ independently tested patterns and consult with an Acoustician or an expert in the field.