HT™ QR Quadratic Residue Diffuser AVL Systems HT™ Quadratic Residue Diffuser is a lightweight acoustical control device for mounting on ceilings and wall surfaces. These products are designed to achieve optimal performance incorporating quadratic residue number sequences and computer modeling analysis combined with laboratory and application testing. AVL Systems HT™ Quadratic Residue Diffusers are manufactured to provide broadband scattering of acoustical sound energy without resonance or high-Q reflections. AVL Systems HT™ Quadratic Residue Diffusers are constructed of multi-density, thermo-molded resins to dampen resonance and resist impact and damage. Diffusers are supplied to finish sizes as specified and ready to install in standard grid ceiling systems and on wall surfaces. AVL Systems HT™ Quadratic Residue Diffusers are ecologically friendly, containing up to 85% recycled materials. Quadratic Residue Number Theory Design Lightweight - For Walls and Ceilings White Finish Standard, Optional Colors Available Class A Fire Rating Reasonably Priced Interactive Performance The AVL Systems families of interactive performance products are designed to provide the acoustical engineer and specifier with a complete toolbox of technically compatible performance products for Home Theatre applications. These engineered products can be used together as an interactive system, working together to optimally enhance the acoustics of any architectural space. AVL Systems offers a full range of acoustic products for virtually every application and technical requirement. Fire Performance Composite assemblies with standard finish will have a flame-spread rating of less than 25 (Class A) per ASTM E-84. Finishes White textured finish standard. Options include a wide selection of AVL Systems' standard fabrics or, Designers selection and C.O.M.   Acoustical Performance (Coefficients) 125Hz 250Hz 500Hz 1KHz 2KHz 4KHz QR™ Diffuser (Absorption) .49 .41 .37 .35 .20 .21 QR™ Diffuser (Diffusion) .68 .75 .85 .82 .72 .59   Products | Absorption | Diffusion | Reflection | Product Applications