[Arny Krueger]

A friend invited me over last night for the unveiling of his new subwoofer
array. It is composed of 4 Fi Car Q18 18" drivers mounted on a heavy wood
plenum that is ducted into his listening room in a corner near his
upper-range speakers.

The Ficar Q18 drivers have Xmax (linear stroke) or 27 mm or about an inch.
They have an approximate additional inch of less-linear travel for a total
of about 2 inch stroke..

Each Ficar Q18 driver has 2 two ohm voice coils that can each handle
sustained power something like 500 watts. My friend drives each voice coil
with one channel of a Behringer EP 2500 power amp, the whole subsystem
driven by a DCX 2496 crossover. Thus, amplifier clipping is avoided. ;-)

Because the drivers are mounted on a plenum, the rear of the drivers
including their electrical terminals can be viewed during operation.
Because he had not yet finished the wiring harness, the 12 gauge stranded
wires leading up to the drivers were simply hanging free, supported the
ends, about 2 feet apart.

The unusual effect was that the 12 gauge wires would flex back and forth
maybe an inch, in synchronization with low frequency signals. This was due
to the interaction between the magnetic field created by the current flowing
through the wires, and the stray magnetic field from the driver's magnet
structure.

I think that this rather visible effect creates a product opportunity for
high end audio ragazine advertisers. "Non-flexing" speaker wires will avoid
the clearly audible (to high end audio reviewers) nonlinear distortion
"caused by the flexing of speaker wires" due to this magnetic interaction.
;-)

BTW, the rest of the system was built to a similar standard. The mid-bass
drivers for each channel were 12" JBL speakers that reminded me of the
classic D123 but they are from the professional sound line. The midrange and
tweeters were JBL compression drivers on appropriate JBL constant
directivity horns. Custom-designed active crossovers with acoustic
Linkwitz-Riley type response provided smooth, effortless and highly musical
listening enjoyment at any sane, and quite a few totally insane SPL levels.

Other than the dynamic range and extended bass, one could probably throw an
acoustically transparent cloth over the speakers and convince most
audiophiles that it was a ribbon or other planar array. It was that smooth
and detailed.

The design goal is something like 126+ dB SPL with low distortion from 6 to
20,000 Hz.

You've heard of pants-flapping bass, right? Well, this system takes things
to the next step. It avoids "pants-leg-flapping distortion" by simply moving
you and the heavy wooden deeply upholstered chair you sit in as one unit.

Seriously, deep loud bass notes simply move you and the chair you sit in
over perceptible distances. It reminded me a bit of riding "Mean Streak" at
Cedar Point. Perhaps my friend's subwoofer should be called "The Mean Streak
Subwoofer" ;-)

Who needs a chair shaker when you can shake the whole room?

[Harry Lavo]

"Arny Krueger" wrote in message
. ..
A friend invited me over last night for the unveiling of his new subwoofer
array. It is composed of 4 Fi Car Q18 18" drivers mounted on a heavy wood
plenum that is ducted into his listening room in a corner near his
upper-range speakers.

The Ficar Q18 drivers have Xmax (linear stroke) or 27 mm or about an inch.
They have an approximate additional inch of less-linear travel for a total
of about 2 inch stroke..

Each Ficar Q18 driver has 2 two ohm voice coils that can each handle
sustained power something like 500 watts. My friend drives each voice
coil with one channel of a Behringer EP 2500 power amp, the whole
subsystem driven by a DCX 2496 crossover. Thus, amplifier clipping is
avoided. ;-)

Because the drivers are mounted on a plenum, the rear of the drivers
including their electrical terminals can be viewed during operation.
Because he had not yet finished the wiring harness, the 12 gauge stranded
wires leading up to the drivers were simply hanging free, supported the
ends, about 2 feet apart.

The unusual effect was that the 12 gauge wires would flex back and forth
maybe an inch, in synchronization with low frequency signals. This was due
to the interaction between the magnetic field created by the current
flowing through the wires, and the stray magnetic field from the driver's
magnet structure.

I think that this rather visible effect creates a product opportunity for
high end audio ragazine advertisers. "Non-flexing" speaker wires will
avoid the clearly audible (to high end audio reviewers) nonlinear
distortion "caused by the flexing of speaker wires" due to this magnetic
interaction. ;-)

BTW, the rest of the system was built to a similar standard. The mid-bass
drivers for each channel were 12" JBL speakers that reminded me of the
classic D123 but they are from the professional sound line. The midrange
and tweeters were JBL compression drivers on appropriate JBL constant
directivity horns. Custom-designed active crossovers with acoustic
Linkwitz-Riley type response provided smooth, effortless and highly
musical listening enjoyment at any sane, and quite a few totally insane
SPL levels.

Other than the dynamic range and extended bass, one could probably throw
an acoustically transparent cloth over the speakers and convince most
audiophiles that it was a ribbon or other planar array. It was that smooth
and detailed.

The design goal is something like 126+ dB SPL with low distortion from 6
to 20,000 Hz.

You've heard of pants-flapping bass, right? Well, this system takes things
to the next step. It avoids "pants-leg-flapping distortion" by simply
moving you and the heavy wooden deeply upholstered chair you sit in as one
unit.

Seriously, deep loud bass notes simply move you and the chair you sit in
over perceptible distances. It reminded me a bit of riding "Mean Streak"
at Cedar Point. Perhaps my friend's subwoofer should be called "The Mean
Streak Subwoofer" ;-)

Who needs a chair shaker when you can shake the whole room

Sounds like an experience, Arny. What kind of cabinetry and room position
did the mid/high speakers have?

[Arny Krueger]

"Harry Lavo" wrote in message

"Arny Krueger" wrote in message
. ..

BTW, the rest of the system was built to a similar
standard. The mid-bass drivers for each channel were 12"
JBL speakers that reminded me of the classic D123 but
they are from the professional sound line.

Therefore, they were built to modern standards, while retaining the
origional short voice coil for low distortion.

The midrange
and tweeters were JBL compression drivers on appropriate
JBL constant directivity horns. Custom-designed active
crossovers with acoustic Linkwitz-Riley type response
provided smooth, effortless and highly musical listening
enjoyment at any sane, and quite a few totally insane
SPL levels. Other than the dynamic range and extended bass, one
could probably throw an acoustically transparent cloth
over the speakers and convince most audiophiles that it
was a ribbon or other planar array. It was that smooth
and detailed.
shaker when you can shake the whole
room

Sounds like an experience, Arny. What kind of cabinetry
and room position did the mid/high speakers have?

The upper range systems were composed of 4 drivers, each built into uits own
ebony-finished approx 20" wooden cube, stacked vertically. The wooden
cubes were off-the-shelf subwoofer enclosures.

[Arny Krueger]

"Soundhaspriority" wrote in message


Did you notice the "Brown Note" effect?

No, mostly because we didn't try to induce it. I've experienced enough of
the brown note effect to believe that with a little more power for a little
bit longer it would be real. There's a similar effect that involves flow
from the other end of the digestive system.

[George M. Middius]

TurdBorg tells the amateurs to BACK THE $(*&% OFF!

Did you notice the "Brown Note" effect?

I've experienced enough of the brown note effect

Come on, now Arnii, that's just not true and you know it's not true. As
one of North America's leading turdophiles, you're sworn to pursue every
possible occurrence of the "brown note". Not to mention brown "food",
brown underpants, and brown checks.

Pay no attention to Turdy's disavowals, Morein. Nobody is deeper into
"brown note" investigations than Arnii Krooborg.