4
Unique
to
the
OPPO
PM
‐
1
is
the
use
of
a
double
‐
sided
diaphragm,
which
allows
us
to
place
twice
as
many
conductors
within
the
magnetic
field
and
eliminate
any
passive
return
zones
where
the
conductors
do
not
work.
This
results
in
the
use
of
100%
of
our
conductor
length,
which
in
turn
results
in
greater
efficiency.
In
addition,
our
flat
conductor
pattern
eliminates
inductance
‐
related
intermodulation
distortion,
common
with
dynamic
headphones,
and
the
OPPO
PM
‐
1’s
purely
resistive
impedance
means
that
sound
quality
is
unaffected
by
a
headphone
amplifier’s
output
impedance.
The
OPPO
PM
‐
1
combines
high
sensitivity
with
low
weight,
allowing
it
to
be
used
freely
with
portable
devices
without
requiring
additional
amplification.
Its
circumaural,
open
back
design
provides
the
best
in
sound
quality
and
comfort,
and
the
overall
rugged
construction
ensures
that
the
headphones
can
withstand
mechanical
and
environmental
stress.
These
aspects
of
the
OPPO
PM
‐
1’s
design
combine
to
provide
a
transparent,
highly
dynamic
sound
that
exhibits
well
‐
balanced
tonal
qualities
with
very
little
distortion,
resulting
in
a
listening
experience
that
is
both
free
of
fatigue
and
capable
of
communicating
every
nuance
of
your
favorite
music.
We
are
proud
of
the
work
we
have
done
with
these
headphones,
and
we
hope
they
bring
you
years
of
enjoyment.
