Selecting a Quadratic Residue Diffuser (QRD) requires a deep understanding of acoustic physics and material science. Buyers must prioritize well-calculated well-depths and widths based on the prime number sequence (e.g., N7, N11, N13) to ensure effective sound scattering. For professional studios, ensure the effective frequency range aligns with your room's needs; typically, deeper wells are required for low-mid frequency diffusion. Material choice is critical: solid hardwoods (oak, walnut) provide superior reflection density compared to lightweight foam, while high-density MDF offers a cost-effective alternative for large-scale installations.