Electro-Voice pro sound news sound innova User Manual

equivalent of your car motor losing power many
times a second. It would be difficult to have a
smooth, controlled speed ride.

To solve this problem, the woofers in the

DVX line have been optimized via extensive
computer FEA (Finite Element Analysis) to have
linear magnetic fields that do not overly modu-
late. With the aid of a laser displacement meas-
urement system, we can also optimize the sus-
pension to not only have the right stiffness but
also to stop the cone motion in a smooth and
controlled fashion when the speaker is pushed
to extremes. What does all this mean to the
prospective customer? Quite bluntly, it means
less distortion under normal conditions and no
rude noises when the speaker is overdriven.

Another problem common to woofers is

that the voice coil of the speaker, like any coil
of wire, has an inductance. Place a hunk of iron
inside a coil and you get even larger induc-
tance. In speaker terminology, we call that
hunk of iron a “pole piece”; every speaker has
one. Most people understand the problems
caused by inductance at high frequencies. Engi-

neers take advantage of inductance all the time
in crossover design. The problem with induc-
tance in a speaker is as follows: As the cone
moves outward, it moves out of the magnetic
circuit and the pole piece is no longer inside as
much of the coil as when the cone is moving
inward. This asymmetry in the inductance also
causes an offset of the speaker’s center posi-
tion, just like a nonlinear magnetic field or sus-
pension. Besides negatively impacting the life
expectancy of a speaker, this asymmetry causes

distortions that are particularly audible and
offensive.

To combat this problem, the DVX woofer

uses multiple approaches. First, we computer-
modeled the magnetic structure and optimized
the geometry to eliminate asymmetries. After
the FEA phase prototyping, the tests and meas-
urements began. The use of multidimensional

measurements using acoustic and laser data
further sped perfecting the design so we could
very quickly identify areas to improve and the
solutions. This enabled a final design that is far
superior to using traditional design methods.

Unfortunately, you cannot simply eliminate

the pole piece from the equation, so we did the
next best thing. We have put a conductive but
non-magnetic ring inside the magnet structure.
Sometimes called a Faraday Loop, this shorting
ring blocks the field from the coil that would in-
teract with the iron core, without affecting the
DC or static field generated by the large ceram-
ic magnet of the motor structure. Another ben-
efit is that is also counteracts the modulation of
the static field that can be caused by the field
generated by the voice coil.

At the end of the day, of course, all this adds

up to a superior-sounding loudspeaker. DVX goes
to show that there is still room for improvement
in the world of loudspeaker design. It’s not just
about the greater overall output. In DVX, the lev-
el of sonic clarity—even for an arena-size system
running extremely high SPLs—is unprecedented.

many different formats. These days that’s a lot,
and it’s getting increasingly difficult to find a
place to store a paper trail of data. Our techni-
cian, Phil Gitomer, insists on having track
sheets and take sheets for every drive or disc.
How many times have you had a hard drive or
tape show up with no documentation? With-
out wasting time mounting it and playing the
material, you have no idea what’s there.

Sometimes it’s hard to get accurate infor-

mation to document. Rehearsal time for live
shows can be short or nonexistent. Getting ti-
tles for classical music movements without a
score, improvisational jazz, or artists and pro-
duction people that won’t give up a set list (or
who even change it without telling audio), and
these days, even guns on stage are all elements
that make obtaining this information difficult. I

would be very interested to hear from you post
guys about what you like to see for documen-
tation. What happens to the paper documen-
tation? Does it get used or tossed? Would you
like to have a CD with the docs on it?

Anyway, back to the theme about getting

more people involved in the production of live
shows and the business of recording them.
One of the ways might be for you to attend a
SPARS meeting in your area. I try to make them
all, gigs permitting. You might just meet some
interesting people and learn something from
their forums. Karen Brinton is more than just
Remote Recording’s boss; she is the current
president of SPARS.

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SPARS

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