Role of a Ferrofluid in a Loudspeaker System

A ferrofluid plays three roles when incorporated into a loudspeaker:

• It conducts heat away from the voice coil
• It keeps the voice coil concentric with the magnet
• It is used as a medium for damping.

Much of the energy that is fed into a loudspeaker is wasted as heat. In order to dissipate some of the heat, heat sinks can be used.

The heat generated by the voice coil will be partly transferred to the top plate of the speaker and the rest by air convection and conduction, which is not a very efficient process.

The build up of heat within the voice coil causes it to expand and can lead ultimately to speaker failure. This expansion will cause the voice coil to scrape the top plate of the loudspeaker. By immersing the coil in ferrofluid, heat is conducted away from the coil much faster, improving the efficiency, and reducing the likelyhood of speaker failure. The magnetic component of the ferrofluid prevents the fluid from leaking away from the air gap, whilst the carrier fluid acts as the medium for heat conduction.

In order to ensure that the fluid remains within the region of the air gap, it is necessary to produce a fluid which is stable. Liquids Research Limited produce loudspeaker fluids of very high colloidal stability, which ensures that the ferrofluid will function correctly during the life-time of the speaker.

Liquids Research Limited manufacture ferrofluids for the entire range of loudspeakers, ranging from tweeters to woofers. All fluids are designed to operate up to 175ºC, though to ensure high performance, operation of the loudspeaker at this temperature for a prolonged period of time should be avoided. All loudspeaker ferrofluids are manufactured from high quality synthetic oils and come in a wide range of viscosity and magnetisation. For an extensive list please download our Download.

All ex-stock fluids are shipped within 24 hours of receipt of a purchase order.

Contact us by email, phone or fax for a prompt quotation and terms