Tyco 579-769 specifications Lobby Example

Applying the Methods, Continued

Example 4: Lobby

During an intelligibility survey in an office building, an employee lobby area measured 0.60 CIS intelligibility, failing the NFPA suggested 0.70. This room is characterized by tile floor, hard walls, and one wall made up mostly of glass, see the figure below. The SPL is adequate at 79 dB for an average background noise level of 47 dB.

		Figure 6-13. Lobby Example
Lobby Example:
•	Dimensions =	24’ L x 16’ W x 10’ H
•	Flooring =	Tile
•	Ceiling =	Acoustic Tile
•	Walls =	Three Walls of Finished Wood, One Glass
•	Ambient Noise =	50 dB

Figure 6-14. Lobby Example

The following basic results are attained from the iTool:

•The iTool reverberation time calculator estimates a reasonable T60 time of 0.62 seconds.

•Using an Edge-to-Edge pattern, the resulting total number of speakers is 4 tapped at 0.25 W, for a total of 1 W of audio power required.

Continued on next page

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