### ASA 124th Meeting New Orleans 1992 October

## 3aSA1. Transfer function magnitude and phase in the awkward zone.

**Richard H. Lyon
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*MIT and RH Lyon Corp., Cambridge, MA 02139
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All systems of finite extent are multimodal, but many have modes so
sparsely distributed along the frequency axis that one can safely deal with
them one mode at a time. This is the classic situation in the dynamics of
machine structures. On the other hand, some systems have modes so densely
spaced that statistical and asymptotic theories such as the geometrical theory
of room acoustics provide powerful models. The low modal overlap theory of
Bolt, and the high modal overlap theory of Schroeder for the transfer function
magnitude in rooms represent these limits in room acoustics. There is a similar
transition in behavior in the phase of transfer functions as one proceeds from
low- to high-modal overlap. This process will be described in the discussion.