Sound Level Meters TW 0 new instruments for the accurate measurement
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of sound levels have been introduced by Dawe Instruments Ltd. The Type 1400F Sound Level Meter is intended for sound level measuments only, whilst the Type 1419A Octave Band Sound Level Meter covers the same loudness and frequency ranges but incorporates eight filters which enable the instrument to be used to determine the frequency characteristics of the sounds measured.
The Type 1400F meter can measure sound levels from 30 to 140 decibels—equivalent to a whisper and a jet aircraft at take off respectively—over the entire audible range from 31.5 cycles per second to 8 kilocycles per second. It is fully transistorized, battery operated and measures only 10.25 in. by 4 in. by 2.5 in., weighing 3 lb. Three small batteries provide the power and give a life of about 60 hours but a mainsoperated power unit can be supplied as an alternative. The instrument which is normally carried in a camera-type leather case with a leather strap is easily held in one hand.
The Type 1419A meter covers the same frequency range as the 1400F but gives a slightly different sound level range— from 24 to 140 decibels—and up to 200 decibels is possible with a special microphone. Power is also provided by three small batteries giving 60 hours' operation with a separate mains-operated power unit available as an option and the unit measures 10 in, by 9.75 in. by 4-5 in. and weighs only seven pounds. It can be easily carried in its leather case with shoulder strap.
Makers: Dawe Instruments Ltd., Western Avenue, Acton. London, W.3.
Price: Type 1400E—£95; Type 1419A—f 160.