Article ID: 13925 
Products
S-Series
Goals
Acoustic properties
Decibel level
Noise level
Solution
Here are the tested acoustic noise generation levels (in dB) for the S-Series products:  Chassis Type   Ambient  Low-Speed  High-Speed
 
S1-CHASSIS        41.5      67.6       76.0
S3-CHASSIS        40.0      65.3       74.6
S3-CHASSIS-POE4   40.0      67.1       74.9
S4-CHASSIS        41.0      66.0       74.4
S4-CHASSIS-POE4   40.5      66.8       75.1
S6-CHASSIS        38.5      63.4       71.1
S6-CHASSIS-POE4   38.5      64.2       71.8
S8-CHASSIS        41.5      69.1       78.0
S8-CHASSIS-POE4   41.5      69.6       78.3
S8-CHASSIS-POE8   41.5      70.4       78.5
SSA S150/S130     38.5      61.7       75.2
Note that high speed is triggered by either a fan failure or an elevated chassis ambient temperature (
13189).
See also: 
13656.