声源（12面体音箱、4292）
简介：
Types 4292-L and 4295 are designed for airborne noise transmission measurements.
特点：
Part of a complete building acoustics system featuring Brüel & Kjær’s Hand-held Analyzer Type 2250 or 2270；
Two omnidirectional noise sources；
Tapping machine for impact sound level measurements；
Remote operation via cable or wireless remote control；
Satisfies national and international standards；
Robust；
Easily portable.
描述：
For most building acoustics measurements, the sound source must radiate sound evenly in all directions to give reproducible and reliable results; therefore, the relevant building acoustics measurements standards (ISO 140 and ISO3382) require the use of an omnidirectional sound source.
OmniPower Omnidirectional Sound Source Type 4292-L uses a cluster of 12 loudspeakers in a dodecahedral configuration that radiates sound evenly with a spherical distribution. All 12 speakers are connected in a series-parallel network to ensure both in-phase operation and an impedance that matches the power amplifier. The entire assembly weighs no more than 8 kg and is fitted with a convenient lifting handle that does not measurably interfere with the sound field.
Key features
Key features of the Type 4292 Light OmniPower sound source:
Lightweight, 8kg assembly making it easy to transport to the measurement location
Powerful, 122dB re 1pW, ideal for measurements in large spaces or for assessing the sound insulation of high performing walls and floors
Powerful at low frequency, delivering peak power where it’s needed most 100Hz – 200Hz ensuring good measurements in high background conditions
Lightweight
The entire assembly weighs a mere 8 kg which for field based measurements often undertaken in multi-storey buildings with stairs and lifts to negotiate, is a welcome light weight alternative to traditional loudspeaker units. The light weight, innovative design is achieved using Neodymium magnets in the 12 speaker clusters rather than the more traditional and heavier ferrous magnet loudspeaker units.
High power at low frequencies
Background noise is the enemy of good building acoustics measurements particularly at low frequencies where traffic noise and air conditioning systems are some of the main culprits i.e. between 100Hz and 200Hz. The OmniPower sound source is designed to deliver its peak performance in this very same range delivering maximum power where it’s needed most.Powered by Power Amplifier Type 2734-A or 2734-B, the Sound Source can deliver a maximum sound power of 122 dB re 1 pW (100 – 3150Hz). The high power output of Type 4292 light makes it ideal for sound insulation measurements or reverberation time measurements
The OmniPower is also fitted with a convenient lifting handle that does not measurably interfere with the sound field as is supplied with a telescopic speaker stand for positioning the sound source at varying heights.