The PMC Prophecy 5 speakers represent a refined evolution of transmission line designs, offering exceptional clarity, balanced sound, and improved room integration for audiophiles seeking high-fidelity audio without the typical compromises of larger floorstanding speakers.
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If someone were to ask me what things
you look for in the design of a speaker,
one of the first things would be,
especially in a floor standing speaker,
a transmission line design. It takes the
back energy from drivers and funnels it
down a tube folded into a labyrinth for
convenience and packed full of damping
material to prevent unwanted frequencies
exiting the line. If designed correctly,
you get a crisp leading edge notes that
rivals the best sealbox speakers and a
bass extension and clarity that most
ported designs can only dream about. The
internal heavy bracing that goes
handinhand with a transmission line
speaker also deals with the main issue I
have with floor standing speakers below £5,000.
£5,000.
They tend to give up too much clarity,
soundstaging, and imaging performance to
equivalent price stand mounts. Even when
they're well constructed, the larger
cabinet and resonances associated with
it are apparent.
Transmission line speakers are more
complex to design and build. Modeling
software these days makes the job a
little bit easier, but the final design
still has to be refined by ear. I can't
think of another manufacturer that's in
existence today and has a stronger
association with transmission line
speakers than PMC. Their new compact
floor standers have been designed to
work in smaller rooms, about the size of
The professional monitor company was
formed in 1990 when Peter Thomas left
his job at the BBC made avail studios
and joined forces with business partner
Adrien Loa.
Right from the beginning, the first
speaker they designed was a transmission
line. The BB5 provided a reference for
many top studios and artists for decades
due to its great power handling and accuracy.
accuracy.
At the end of 2024, PMC launched their
new Prophecy range of speakers, a stand
mount, a center channel, and three floor
standers, replacing the 25i range. The
Prophecy 5 is the most compact of the
three floor standers, smaller and also
cheaper than the 2523i
it replaces. PMC claimed that the
reduction in base extension is minimal,
but the new speakers work better in
small to mediumsiz rooms.
The Prophecy Fives are priced at £4575
mm or 35.4x
6.5x 10.2 in. Each speaker weighs 17.7
kg or 39 lb. Three engineered wood
finishes are available, black and
walnut, natural walnut, and the medium
oak seen here, tipping the cap to sustainability.
sustainability.
PMC have been refining their designs
with each generation and the prophecy is
no different. Although the labyrinth
dealing with the backwave energy from
the midwuffer is familiar. What PMC
referred to as advanced transmission
line or ATL.
However, the previous generation had a
grill at the exit of the line which has
now been replaced by a solid piece of
extruded aluminum forming the entire
base. Termed Laminer X. It lowers the
center of mass and improves air flow,
reducing turbulence and harmonic
distortion by up to 3dB. According to PMC,
PMC,
the drivers have been customized to work
with the new cabinet, but are variants
from those used in PMC's professional
line of studio monitors. There's a 27 mm
1.1 in soft dome tweeter sitting in a
wave guide and covered with a grill to
aid dispersion.
At 1600 hertz, the 125mm 5-in mineral
cone midwuffer takes over. The tweeter
is able to play lower than usual due to
its size and the wave guide acting as an
acoustic amplifier.
No doubt it's a deliberate design choice
by PMC to move the crossover frequency
away from the 2,00 to 3000 hertz range,
which is where our hearing is most
sensitive to changes and is the typical
crossover point for most two-way designs.
designs.
The crossover uses high order slopes and
good quality capacitors. There's an air
core inductor on the tweeter network and
an iron core one on the midwuffer. The
military grade circuit board with thick
copper tracks and gold plating inspires confidence.
