Twin cone drivers. Why? And do they work?

[Big Chris]

After posting a pic on the oldest hi-fi thread, I see my old Hitachi portable stereo had twin cone drivers.

I don't know what purpose they serve. Obviously, there's no seperate movement as the smaller cone is glued to the larger cone, so I was just wondering what (if anything) they acheieve.

Can someone enlighten me?

 

[Anonymous]

The small cone in the centre is known as a whizzer cone.

It extends the upper frequency response range of the driver.

It was particularly popular in automotive applications to provide a pseudo-full range response driver. Could still be being used for all I know.

Sometimes it is augmented by a radiating dust-cap in the centre of the driver, further extending its response.

It's a cost-effective way of extending frequency response. Cheaper than a separate tweeter.

A quick google on whizzer cone will give you all the tech.
hth

 

[Big Chris]

Gary Mardell:The small cone in the centre is known as a whizzer cone. It extends the upper frequency response range of the driver. It was particularly popular in automotive applications to provide a pseudo-full range response driver. Could still be being used for all I know. Sometimes it is augmented by a radiating dust-cap in the centre of the driver, further extending its response. It's a cost-effective way of extending frequency response. Cheaper than a separate tweeter. A quick google on whizzer cone will give you all the tech. hth

Excellent. Cheers Gary.

I think those Beauhorn BBC2 Logo-alike speakers use twin cone drivers too.

 

[Anonymous]

Glad to be of assistance.

They're a very space-efficient way of achieving full-range driver response. IIRC thr Rehdekos also used drivers with whizzer cones. So they're not necessarily confined to low-end product. But they have obvious cost benefits over a two-way design such as an ICT, Uni-Q or a Dual Concentric driver.

I'd guess that the shape, size and mass of the whizzer can be altered to change the directivity and output characteristics.

Why is there never a transducer engineer around when you need one? 🙂

 

[Anonymous]

It's also a way to extend response without suffering from crossover distortion (or passive component insertion loss).