for speedy bass , not necessarily the most bass, I favour Qtc at 0.5 to 0.6 for a sealed box.

Thus I would trade , for a given allowable box volume a 12inch for a 15 inch to achieve it.

I am wary of too much equalisation and electronics ahead of it as with more supplies, power noise, extra ground routes

immediacy and fidelity may be impaired in favour of a notional text book frequency response.

The box size implies lots of panel area, so massive bracing and damping is a prerequisite if the journey is to be worth the effort and expense.

Martin Colloms

DM will have to work hard to define the design and try to exclude the noise from all our suggestions.

Thiel and KEF have been working towards coincident, time aligned driver systems with proprietary drivers. The Quad gets there as of right.

Avalon is more time coherent than most with low diffraction narrow enclosure forms , tilted back to align the bass mid and treble start positions relative to the listener.

The resulting system CSD is particularly good, thanks to careful control of the effective driver working ranges. With these designs it is the attention to such detail which impresses.


My instinct for an enthusiast is a sealed box three way with a form narrowing with height, a true 8ohm impedance, , ie two of the '5ohm' bass drivers in series probably 220mm SEAS , .

probably the 160 mm Scan pulp cone wide range mid and a DXT soft dome tweeter.

We could try and firm up device type numbers from this broad suggestion.

Martin C