Cabinet shape and driver placement materially govern diffraction distortion

Evidence

In 1950, Olson (1969) demonstrated, experimentally, that the enclo­ sure shape and size significantly affect the frequency response of a loud­ speaker, due to diffraction effects. These diffraction effects can occur at any frequency where the wavelength is of similar size, or smaller than the box. This means that they can occur in any small enclosure, such as a top mounted tweeter. They can also occur in the main cabinets if there are drivers whose frequency ranges produce wavelengths of appropriate dimen­ sions relative to the box sizes. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2198 (#corroborates, via linked claim)

In the context of loudspeaker design it is the bounded to unbounded case that is important as this is what happens when a sound wave from a loudspeaker reaches the edge of the front face of an enclosure. In this situation, the wave is making a transition from being bounded by the front of the enclosure to being unbounded, as shown in Figure 6.63. The con­ sequential reflections cause disturbances to the frequency response of the loudspeaker because they interfere with the main output. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2199 (#corroborates, via linked claim)

Categorization

• XREF: connects to: Off-center driver mounting only partly reduces cabinet edge diffraction.; Centrally mounted drivers between two enclosure edges worsen response via coincidence effects; Loudspeaker enclosure shape and size alter frequency response via diffraction — David Howard, Jamie Angus, coustics and Psychoacoustics, 2198 (+6 more)

Broader Connections

• Loudspeaker enclosure shape and size alter frequency response via diffraction #corroborates (0.95) — David Howard, Jamie Angus, coustics and Psychoacoustics, 2198
• Sound waves diffracting at speaker cabinet edges distort the frequency response #corroborates (0.95) — David Howard, Jamie Angus, coustics and Psychoacoustics, 2199
• Loudspeaker enclosures should curve near drive units to reduce diffraction #expands (0.92)
• Edge diffraction sources can be canceled by out-of-phase speakers #expands (0.80)
• Asymmetric board shapes reduce acoustical short-circuiting by unbalancing antinodal regions #expands (0.75) — Eric J. Heller, Why You Hear What You Hear- An…, 1179