More than a passing resemblance to Spongebob Squarepants and Yosemite Sam too? :^)

t_bone April 01, 2010 11:23

I have a JF-1 but haven't yet set it up. One needs two 2-channel power amps or 2 pairs of monoblocks. The top three channels are run through the passive. I can forward the original manual of the JF-1 in PDF form if you want. I know nothing about the paint.

t_bone March 07, 2010 09:41

Jadisboy,
Congratulations on your speakers. I hope you are enjoying them as much as I
do.

Johnk,
The mid-bass horn is 68cm wide at the widest inside point just near the top.
And from the middle of the inside top edge to the top of the treble wood horn
it is also 68cm. The horn is 3cm thick at all the outside edges. From the
inside of the horn (the inside edge of the throat) to the middle of the inside
top edge, it is 76cm. From the same inside of the throat 'lip' to the inside of
the middle of the vertical edge (where I view the axis to be), it is 79cm.
Horizontally across the middle (inside edges again) at or near the axis point,
it is 57cm wide.

As you can see on Jadisboy's left speaker, the top side of the flare appears to
be more acute than the underside - that is not an optical illusion; it looks
that way on mine too. Measurements show that if one draws a straight line
from the top external edge of the throat to the top external edge of the front,
the maximum distance from that straight line to the horn is 9.5cm. On the
sides it is 8cm. On the bottom of the horn it is 5cm.

On mine I have no labels on the drivers, but I do remember that it uses an
Audax 6.5" PR170MO driver for the mid-bass. I have just found a
reference I had written down suggesting Beyma and Fostex drivers on the top
(no info on the bass units). I thought I had a pdf copy of the Stereophile
review of the speakers which would give a bit more info but I cannot find it
now. The magic is obviously in the horn, the crossover points, and the
crossover itself, rather than the mid-bass and treble drivers themselves. It
might be that much better using top-notch drivers (though I've heard the
Audax in other hi-eff applications and it has sounded quite good there too -
great dynamics), but given the efficiency of what is in there and the horns,
the drivers are certainly not working too hard.

The bass has two bottom-firing woofers (actually, the outer-facing one is
bottom-firing; I can't remember if the one above is wired in or out of phase)
per side in an isobaric arrangement inside the cabinet with no parallel sides. I
expect they are wired in parallel (expected use of crossover/biamping). Jadis
made an electronic (tube-based) 2-way crossover (Jadis JF-1) so people
could biamp the speakers (running the bass directly and the mid/treble
through the passive crossover I think). The crossover point is supposedly
180Hz.

Please send me mail if you have any other questions on measurements/etc. I
will do what I can. I would be interested to see what comes out.

It would be easier to use a 150Hz horn such as the Oris150 or an Azurahorn
and then add the other units where needed. I think the only way the bass
works in that size a box is because of the isobaric nature of the woofers, and
it does pretty well (and goes waaay deep, which is great - the best bass is not
always that which goes deepest, but once you get really good bass down
deep, one does not want to go without - and it just makes the treble that
much better).

t_bone March 07, 2010 02:34