Page 224 - Master Handbook of Acoustics

FIGURE 11-11 Reverberatory decay with a double slope due to acoustically coupled spaces. The
shorter reverberation time represented by slope A is that of the main room. A second, highly
reflective space is coupled through an open doorway; its longer reverberation time is represented by
slope B. Those seated near the doorway are subjected first to the main-room response and then to the
decay of the coupled space.

Electroacoustically Coupled Spaces

What is the overall reverberant effect when music recorded in a studio with one reverberation time is
reproduced in a listening room with a different reverberation time? The sound in the listening room is
indeed affected by the reverberation of both studio and listening room. This is demonstrated as

follows:

• The combined reverberation time is greater than either alone.
• The combined reverberation time is nearer the longer reverberation time of the two rooms.

• The combined decay departs somewhat from a straight line.
• If one room has a very short reverberation time, the combined reverberation time will be very
close to the longer one.

• If the reverberation time of each of the two rooms alone is the same, the combined
reverberation time is 20.8% longer than one of them.

• The character and quality of the sound field transmitted by a stereo system conforms more
closely to the mathematical assumptions of the above than does a monaural system.
• The first five items can be applied to the case of a studio linked to an echo chamber as well as
a studio linked to a listening room.