"The
Manhattans"
A while ago I was
given a pair of Kef Concertos (I think) with the B139 woofer and T15
tweeter. The cabinets were very water damaged. Knowing that
the B139 has issues up in its midrange band, I decided to add a mid
driver. The Vifa C13WG was available at a half price sale and was
the obvious candidate, being that is looked sort of like a Kef
B110. The T15's were getting on a bit and a Foster ribbon driver was
available at a low price to augment its top end.
The result was a 4-way speaker. Initial x-o points set at 220, 1500
and 7500, but will probably end up around 275, 1500 and 9000.
It was decided to put
the Kef B139 in a TL cabinet, the final dimensions being very close
to those used in the Rogers L/S speaker, but with a slightly
difference in driver position. This was constructed as a
single cabinet so that I could play with it later if I wanted.
The Vifa C13, Kef T15
and Foster ribbon were put into a sort of pyramid cabinet with the
drivers as close as possible together. A slight sloped baffle
was applied to try to vertically align the drivers as much as
practicable.
Because there was
little room for big coils in the top unit, it was decided to use a
split series x-o, in a 3-way linked + cascaded bass. This
meant only 2 wires needed to be connected to the top unit.
These were connected via magnetic connectors from the Jaycar
security components catalog. These seem to give a very good
connection. If they prove to be unreliable, I'll look for some sort
of spring pressure contact.
Here are pics of the
the progress speaker and probably x-o design
One day I will actually get
around to painting or otherwise finishing these speakers !!