Non-parallel walls do not eliminate room modes

Evidence

A recurring fantasy about rooms is that if one avoids parallel surfaces, room modes cannot exist. Sadly, it is incorrect. Among the few studies of this topic, Geddes (1982) provides some of the most useful insights. He found that “room shape has no significant effect on the spatial variations of the pressure response” … “the spatial standard deviations of the p2 response is very nearly uniform for all the data cases [the five room shapes evaluated in the computer model].” Source location was a factor in the behavior of the modes of course, as was the distribution of absorption. “Distribution of absorption was far more important in the more symmetrical shapes—[a non-rectangular] shape did help to distribute the damping evenly among the modes” (Geddes, 2005). It seemed that the most effective modification to a rectangular room was to angle a single wall. — , Toole, Floyd E - Sound reproduction-…, 912

A recurring fantasy about rooms is that if one avoids parallel surfaces, room modes cannot exist. Sadly, it is incorrect. Among the few studies of this topic, Geddes (1982) provides some of the most useful insights. He found that “room shape has no significant effect on the spatial variations of the pressure response … the spatial standard deviations of the p2 response is very nearly uniform for all the data cases [the five room shapes evaluated in the computer model]”. Source location was a factor in the behavior of the modes of course, as was the distribution of absorption. “Distribution of absorption was far more important in the more symmetrical shapes—[a non-rectangular] shape did help to distribute the damping evenly among the modes” Geddes (2005). — Toole, Floyd E, Sound reproduction- the acoustics and…, 1552

Categorization

• SEED: Article angle: the persistence of acoustic myths in internet forums despite decades of settled peer-reviewed literature, using the parallel-wall myth as a case study.
• DEFINE: Clarifies that room modes arise from the enclosure and source/absorption distribution, not wall parallelism; a common studio-design myth is corrected here.
• corroborated: 3 independent passages support this claim — , Toole, Floyd E - Sound reproduction-…, 912; Toole, Floyd E, Sound reproduction- the acoustics and…, 1552
• XREF: connects to: Reshaping a room’s walls only obscures resonances rather than removing them

Broader Connections

• Reshaping a room’s walls only obscures resonances rather than removing them #corroborates (0.92)