Riverbank Acoustical Laboratories
RAL has six reverberation chambers available for acoustical materials testing, as well as a fully equipped machine and tool shop. All tests being conducted in the reverberation rooms are monitored in a central control room.
Networked test systems control the data acquisition, evaluation, and report generation. Printouts, including the data and graphical presentation, are available to the client immediately following the completion of each test.
Clients have access to a private office for their exclusive use, a conference room and a large lecture hall with audio-visual equipment. The laboratory also houses the Riverbank Acoustical Museum and Acoustical Library.
Test Room #0
One of the first of its kind in this country, Room 0 is a highly reverberant sound chamber with a volume of 292 cubic meters. This room is isolated within a second room that, in turn, is located inside the main building. Both the test chamber and second room have 45 cm thick walls and 68 cm thick ceilings.
Because of stringent temperature and humidity requirements designated by certain acoustical test standards, Room 0 is controlled within 1°C and 2 percent relative humidity for each test. The chamber has the necessary fixed and rotating diffusers in order to randomize the sound field. Room 0 is primarily used for sound absorption, sound power and sound pressure and dB(A) type measurements. Adjacent to Room 0 is a temperature-controlled work and curing area where specimens can be prepared before testing.
Test Rooms #1-4
Each of these temperature and humidity-controlled test chambers contain 50 cm thick walls consisting of two separated columns of high density solid concrete blocks. Thus, after a test specimen is installed between Rooms 1 and 2 or Rooms 3 and 4, there are four block walls totaling 100 cm of mass and separating airspaces to avoid sound escaping into the adjacent room by other routes (flanking paths).
In order to achieve high ratings on various test assemblies, double metal flanking shields have been installed to provide additional isolation. The laboratory walls, poured concrete floors and pre-stressed, reinforced concrete ceilings contain the appropriate isolation and flanking path eliminators required for sound transmission and sound impact tests. Fixed and rotating diffusers are in place to provide a randomized sound field to satisfy precision requirements.