Acoustic absorption is the key to this line! Go with our 2" Wedges when you're trying to tame frequencies in smaller areas. These are our most popular seller and work great with most acoustical needs. Our 3" Wedges are better at absorbing low-end frequencies than the 2" version. Medium sized areas will appreciate the acoustic accuracy of the 3" wedges. 4" Wedges are best for larger sized areas with bass control issues. If you need maximum acoustic control and sound accuracy, 4" is the size for you.