Diffusor effectiveness in small listening rooms lacks subjective validation

Evidence

If control of a specific reflection is required over a wide bandwidth, the necessarily thick resistive absorber might remove too much energy. Curved surfaces and irregular masonry surfaces have been used to scatter incident sounds in a variety of directions, thereby attenuating, not eliminating portions of the spectrum. Engineered surface diffusers are another option. With these devices incident sound energy is scattered over wide angles, attenuating the energy in any one direction, and adding multiple versions of it from each of the prominent surface features, spreading the energy out in time. Instinct says that both are useful behaviors, but one needs proof. Unfortunately, there seems to be very little. There are mathematical modeling exercises, many focused on performing spaces where increasing reflections/diffusion is the objective. In small listening rooms diffusion is not a goal. In small listening rooms, where they tend to be used as an alternative to absorbers, there is limited information and the subjective side of the scientific balance is substantially missing. — Toole, Floyd E, Sound reproduction- the acoustics and…, 652

Categorization

• QUESTION: Why has diffusion in small rooms gone so under-researched subjectively while mathematical modeling abounds? A gap worth chasing.