Of the 50 new Japanese mobile phone models announced for 2010, almost one in four will be waterproof mobile phones, one of numerous indicators of a growing trend towards the waterproofing of mobile equipment. Given there are so many different areas that require waterproofing, there were many technical challenges and cost issues to overcome when developing the waterproof speaker. Conventional methods of waterproofing dynamic speakers used waterproof sheets which covered the output sound holes, reducing sound quality. Murata’s approach incorporates a rubber film into the speaker itself, leaving the output sound holes open. The width of the metal frame housing the speaker has been increased to improve the seal between the metal frame and the chassis, preventing water penetration.
The new waterproof speaker has been designated part number VSLBG1914E1400-T0. Its average sound pressure level (SPL) is 92.0±3.0dB (1500Hz/2000Hz/2500Hz/3000Hz average) with a resonant frequency of 1400Hz±20%. Since no magnets are used, there is no possibility of malfunctions caused by iron sand, or electromagnetic effects on magnetic sensors.
