• Campbell Associates


Why use a dodecahedron speaker for sound insulation testing? Are light-weight speakers really up to the challenge?

New building constructions often have much better sound insulation than previous constructions we are used too. It is therefore important that the emitted sound power is as high as possible in order to get a good signal to noise ratio in the receiving room. A dodecahedron speaker (12 speakers) are perfect because they radiate the sound evenly from the speakers on all sides. This ensures the room is excited with as much sound as possible and ensures a reliable test environment on-site to save you time.

The below image illustrates the theoretical difference between using a cabinet speaker and a dodecahedron speaker for sound insulation testing and clearly defines why a dodecahedron speaker is a must-have for reliable results.

The Nor276 speaker (pictured right) is designed to conform to ISO140-4 and ISO16283-1. It is lightweight and convenient to carry around the site, up and down several floors with ease, with a Nor280 amplifier weighing less than 3.5kg.

Norsonic speakers and amplifiers are therefore designed to be extremely powerful and lightweight with on-board signal generators and equalisation, ensuring that the power is distributed to the frequencies that are required. These are contrary requirements are not easy to achieve with standard commercial equipment.

The challenge in warmer test environments is that when speakers and amplifiers are continuously driven, the thermal energy generated by the equipment can have a reducing effect on the output of the speaker.

Speaker design is therefore critical to overcoming this challenge to avoid a cooling delay. The low weight of the Nor276 speaker (which is less than 9 kg) has been obtained using specially designed loudspeaker elements with neodyme magnets without detriment to the speaker's performance. Thermal dissipation is controlled by the amplifier and speaker to ensure a maximum and reliable output while ensuring the equipment is lightweight.

The Nor276 has been designed for continuous operation for more than one hour at full power.

The Nor280 power amplifier has an equalisation circuitry matched to the loudspeakers Nor276, designed to boost the high and low frequencies to improve the system performance when used for building acoustics.

The sound power graph below includes the sound power spectrum with the effects of the equalisation circuitry.