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SDS Acoustic Enclosure tames 1000bhp, reducing 109dB(A) to 79dB(A)

Sound Damped Steel designed an enclosure for an engine test facility where engines up to 1,000 horse power are dyno tested, the problem was extremely challenging. Prior to the SDS installation conversation in the entire factory and offices was impossible, neighbouring factories were complaining about the noise and had even bought there own noise meters to monitor the noise from this location. After the installation normal conversation could take place beside the enclosure. 
The enclosure needed observation windows which were 10mm thick polycarbonate and access doors large enough for a forklift to drop the massive engines in place. The steel used was 2mm SDS damped which controlled the radiated noise and lined with 50mm SDS HiMass foam which reduced the airborne noise. An extraction system was included to ventilate the enclosure to remove fumes & heat from the test bed. The first part of the clip shows a motor on full revs without any enclosure in place, the reading peaked at 110dB(A), it then shows the enclosure in place with the doors open which gives a reading of 99dB(A), as the doors close the reading drops to 79dB(A). This reduction has removed more than 99% of the original power level.
The next phase shows the motor on tick over, with the doors open the noise is 94dB(A) reducing to 69dB(A) with them closed. Again this is a power reduction in excess of 99%.