On almost a daily basis, we have customers asking about the difference between acoustic panels made from Owens Corning 703 and panels made from mineral wool (rock wool). Many of them have visited different acoustic/AV forums and have heard “OC703 purists” saying that nothing works as well as 703/705. However, acoustical lab tests show that even though Owens Corning 703 and 705 are great products, their performance is nearly identical to mineral wool.

This makes sense, because when the thickness, fiber structure, and density of two materials are the same, the sound absorption will be the same too.

You can take a look at test results for the different types of acoustic material we sell on our selecting the right acoustic material page. You can see from the test data that Roxul AFB (mineral wool) is very comparable to Owens Corning 703, as Roxul Rockboard 60 is to Owens Corning 705.

To match the low frequency performance of Owens Corning 703 4″, simply stack two pieces of Roxul Rockboard 60 together to create a 4″ thick panel.