How does an exciter work?

An exciter (a.k.a. vibration transducer, bodyshaker), as a loudspeaker without a membrane, comprises three essential components: an oscillating mass (1), a contact terminal (2) for electrical connection to the amplifier, and a mounting plate (3) for fixing to the installation surface.

By applying a signal to the contact terminal, the oscillating mass vibrates. The vibration is transmitted to the mounting plate and is passed on to the plate to be excited. The excited plate then emanates the music or speech signal. In this respect, the function of an exciter is similar to that of a standard loudspeaker.

he sound emission of the exciter works on a slightly different principle. Compared to a conical and very light loudspeaker membrane, the heavy, flat plate to be excited can hardly vibrate in a piston-like manner. Instead, bending waves, i.e. wave-like oscillations that emit sound, spread out across the excited plate. The quality of the music or speech signal reproduced depends very much on the material, dimensions and shape of the plate to be excited.

• Mounting method: Depending on type, the exciter is fixed to the installation surface using adhesive and/or screws, ideally on a flat, clean surface, with its entire base plate flat. The adhesive has to suit the material of the installation surface. High-strength contact adhesive, silicone, high-quality double-sided adhesive tape with long-term stability, etc. are all suitable. Exciters with a threaded bushing instead of a mounting plate require a matching threaded bolt that, in turn, is well fastened to the installation surface.

• Mounting position: Good results are achieved with a mounting position slightly off-centre in relation to the excited surface. To determine the most favourable mounting position, it makes sense to experiment with measurements and listening tests, because the acoustics depend strongly on the material and shape of the plate. For test mounting, standard double-sided adhesive tape can be used. To test difficult-to-access attachment positions, the exciter can be mounted provisionally on the "front" of the plate to be excited.

• The larger the plate, the more low-frequency sound components are reproduced and the "fuller" the sound. Conversely, with smaller plates the sound is "thinner."
• A light plate has advantages, with efficiency (sound pressure level to input power) decreasing as weight increases.
• The plate should be as rigid as possible.
• If possible, a non-magnetic material should be chosen. The exciters contain a permanent magnet and would therefore be pre-tensioned if attached to a magnetic surface.
• The shape of the plate has a major effect on the sound. Components with few stiffeners and large surfaces have a positive effect. But many other shapes also work well.
• Wiring: When routing wires, it is important that their resonance does not lead to noise, e.g. if they bang against a metal plate. If necessary, wires can be sheathed with foam.

Disadvantages
• Lower efficiency compared to standard speakers (more amplifier power required)
• Potential for annoying vibration noise from components that come into contact with the excited plate
• Acoustics are strongly dependent on material, dimensions and shape of the plate to be excited

Advantages
• No negative influence on design, as the speaker can't be seen
• Ideal protection against environmental influences (weather, water, cleaning agents)
• Excellent protection against vandalism
• Easy to install
• Very good sound is possible due to wide sound dispersion angle

We offer a range of exciters of manufacturer and speaker specialist Visaton direct from stock

For any questions about these speakers, our sales team will also be happy to advise you.