Carbon Dating

AE’s flagship 500 series introduces its first carbon drivers and David Price thinks this floorstander is a real fibre-provider

- David Price

Few things are ever new in loudspeaker design, but progress sees the same ideas coming back in ever more diverse forms. In the case of the new AE509, we see the reappearance of carbon fibre driver cones and domes. Various companies from Audax to Sony have designed and manufactured these over the years, and with good reason because it is a far lighter material than many others – so can surely only be a good thing.

The AE509 has twin custom-designed carbon fibre mid/bass units working together with a bespoke carbon fibre tweeter. This confers several immediate and important benefits. Because the material is – according to AE designer Mat Spandl – half the weight of the company’s former aluminium cones, it offers better transient speed and is less power-hungry. Also, because all the drivers use the same carbon fibre weave, they integrate better in the time domain. Finally, because they share the same material, there’s tonal consistency to all frequencies. This cohesion is aided and abetted by the natural self-damping that the material has, claims the designer.

I’ve seen various carbon fibre drivers over the years, but it’s rare to see a dome tweeter made from this material. The lighter and better damped the dome is, the smoother, less coloured and faster the sound. This 25mm unit replaces the heavier aluminium dome used on this speaker’s predecessor. It partners two 125mm drivers with cast aluminium baskets, metal dust caps and a new 35mm voice coil. The speaker is a two-way configuration, but with a midrange-tweeter-mid/bass (MTM) driver layout, with high voltage polypropylene film-wound capacitors and air core inductors used in critical locations in the crossover. The business is done at 560Hz and 3.1kHz, meaning the tweeter handles unusually low frequencies for a design such as this.