Infinity PRELUDE FORTY User Manual

INFINITY®PRELUDE®FORTY

LOUDSPEAKER

ENGLISH

OWNER

’

S GUIDE

INFINITY®PRELUDE®FORTY

This loudspeaker system represents a refinement of the principles that
have guided Infinity
Loudspeaker development is generally an evolutionary process. New models
usually perform slightly better than the ones they replace. Over time, the
subtle advances add up and, when the latest model is compared to a loud­speaker that is 10 or 12 years old, the improvement is unmistakable.

Every once in a while, a loudspeaker is developed that transcends this
pattern – its performance so remarkable, its design so stunning, its tech­nology so advanced, it can truly be described as revolutionary. The new
Infinity Prelude

The Infinity Prelude Forty 3-1/2-way design utilizes dual 8" CMMD
four patent-pending Maximum Radiating Surface
drivers and an all-new 1" CMMD high-frequency driver. With its proprietary
Ceramic Metal Matrix Diaphragms, flat-panel MRS drivers and a sophisticated,
yet refined, crossover network, the Prelude Forty speaker will breathe
life into any musical performance and touch the soul of the listener. The
Infinity Prelude Forty system is one more landmark in a 40-year quest
to apply “science in the service of art.”

®

loudspeaker designs for more than 40 years.

®

Forty loudspeaker system is an elegant case in point.

®

™

(MRS™) mid-bass/midrange

woofers,

TECHNOLOGY

The Prelude Forty system incorporates several innovative technologies that,
when implemented by exceptional engineering talent after hours upon hours
of subjective listening evaluations, result in a loudspeaker that realistically
and accurately reproduces the signal source with minimal distortion
and coloration.

CERAMIC METAL MATRIX DIAPHRAGMS (CMMD®)

For decades, loudspeaker engineers have known that the ideal transducer
should be stiff, yet light, and have high internal damping (i.e., a material’s
ability to absorb energy). The Infinity CMMD transducer is a significant
advance in transducer technology. Ceramic offers better performance
than that of other materials. Ceramic is stiffer than metals and lighter
than plastics and typical composite materials, in addition to offering
improved damping. These ceramic-based transducers take us a giant
step closer to the ever-elusive “ideal transducer.”

CMMD technology offers accurate pistonic operation over the entire audible
frequency range of the driver, completely eliminating coloration due
to diaphragm breakup and dramatically reducing distortion. And when
ceramic-metal-matrix transducers are exposed to moisture, sunlight or
extreme temperatures, their performance does not deteriorate.

CMMD T

ECHNOLOGY

Optimizing the parameters of the Prelude Forty flat-panel diaphragms
presented a serious engineering challenge. But by reinforcing the patented
Ceramic Metal Matrix Diaphragms with strategic ribs and gussets, Infinity
engineers were able to strike the perfect balance between electro-acoustic
efficiency and reliability.

D

UAL ELLIPTICAL VOICE COILS

Another flat-panel challenge was finding a way to uniformly drive as much
of the diaphragm’s radiating surface as possible. A traditional cone is only
driven by a small voice coil at its apex, but flat panels require a completely
different approach. Infinity engineers developed dual elliptical voice coils
for the MRS drivers. With more than six times the voice-coil contact of a
typical cone transducer, they move the diaphragm much like an ideal piston,
for superior operation throughout the driver’s entire frequency range.

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REATER DYNAMIC RANGE

In addition to driving the flat diaphragm more uniformly, the dual elliptical
voice coils offer another benefit. The greatly increased surface area of
the coils allows them to dissipate heat more efficiently, reducing thermal
compression and dramatically increasing the speaker’s dynamic range.
The result is increased sonic clarity with reduced distortion.

TRANSDUCERS

In addition to CMMD technology, all the transducers incorporate advanced
neodymium motors that are inherently magnetically shielded. The 8"and
MRS frames are constructed of cast aluminum and have been optimized
to reduce resonances through proprietary FEA computer modeling and
scanning laser vibrometer measurements. This ensures minimal distortion
and incomparable performance.

The 8" low-frequency transducers are the embodiment of uncompromised
driver design.The ceramic-metalmatrix cone is attached to a rigid cast­aluminum frame, through a compression-molded, butyl-rubber surround.
The motor assembly incorporates a vented polepiece for maximum heat
dissipation with negligible air turbulence. The motor structure uses a 2,"
edge-wound, copper voice coil for high power handling and minimal
power compression.

To maximize system performance, the flat-spider assembly and the cone are
mounted to different points on the fiberglass former, increasing reliability
and reducing distortion, especially at high output levels. An extra-thick top
plate and dual-magnet structure are utilized to allow for huge peak-to-peak
driver excursions, with significantly lower distortion and a more linear
frequency response than is true of typical drivers.

MAXIMUM RADIATING SURFACE™(MRS™) DRIVERS

The appeal of flat-panel transducers has never been more obvious, and
the basic technology behind them is straightforward enough. But earlier
flat panels had performance limitations in the low frequencies, and were
prone to thermal compression. In developing the MRS transducers, Infinity
engineers incorporated new materials and technologies that have overcome
the drawbacks and deliver significant performance benefits.

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INFINITY PRELUDE FORTY

ROOM-FRIENDLY ACOUSTICAL DESIGN

Driver quality is not the only requirement for exceptional performance.
Infinity engineers understand that the room in which the loudspeaker
is placed can greatly affect its performance. To ensure that the Prelude
Forty system will sound exceptional in even the most unexceptional listening
environment,Infinity engineers have developed techniques to solve the
most serious room-generated problems having to do with loudspeaker

directivity and which can affect the reproduction of mid and high frequencies.
One characteristic of forward-facing loudspeakers is that the sound output
lessens as one moves away from the principal axis. If the dispersion
characteristics of the loudspeaker are different at various frequencies,
the reflected sounds will be very different in quality both from each other
and from the first (i.e., direct) sound. The ears don’t ignore these differences;
they perceive them as coloration, or as sound quality that has been degraded.
The Prelude Forty system has been carefully designed to maintain a directional
pattern that is similar at every important angle, on and off axis. The positive
result is that both direct and reflected sounds arriving at the listeners’ ears
have similar timbral signatures.

An all-new, controlled-directivity waveguide ensures smooth high-frequency
delivery across the entire listening area and increases high-frequency
efficiency, lowering distortion and improving dynamic range.

It is hoped that you have enjoyed this brief introduction to the technology
of the Prelude Forty loudspeaker system. If you would like to further
explore the technology and design of the Prelude Forty system, please ask
your Infinity dealer for the CMMD and MRS white papers. The white papers
can be downloaded from www.infinitysystems.com.

UNPACKING THE PRODUCT

Finish unpacking the speakers and check the contents. If you suspect
damage from transit, report it immediately to your dealer and/or delivery
service. Keep the shipping carton and packing materials for future use.

INCLUDED:

1 x Prelude Forty loudspeaker
1 x Upper grille
1 x Lower grille
1 x Left woofer grille
1 x Right woofer grille
4 x Spikes
1 x Owner’s manual
1 x USA warranty sheet

ASSEMBLY

INSTALLING SPIKED FEET

Four metal spikes are supplied for use when using the speaker on a carpeted
surface, to decouple the speaker from the floor and prevent unwanted
damping. To insert the spikes, gently lay the speaker on its back on a soft,
nonabrasive surface. Each spike screws into the threaded insert in each
outer foot. Make sure all four spikes are screwed in completely for stability.

NEVER drag the speaker to move it, as this will damage the spikes, the
feet and/or the wood cabinet itself. Always lift the speaker and carry it
to its new location.

INSTALLING GRILLES

Top Grille

1. Insert the two pins into the rubber cups located in the top of the logo bar,

as shown in the front view in Figure 1.

2. Let the magnets draw the top of the grille against the driver trim area,
as shown in the side view in Figure 2.

Magnets

Figure 1. Figure 2.

Bottom Grille

1. While holding the grille at a 45-degree angle to the speaker, insert the

two hook tabs into the two slots on the underside of the logo bar,
as shown in the side view in Figure 3.

2. Let the magnets draw the bottom of the grille against the driver trim
area. Ensure the hook tabs are properly engaged in the slots of the
logo bar to properly support the weight of the grille,as shown in the
side view in Figure 4.

Magnets

Figure 3. Figure 4.

Side Grilles

1. Insert the six grille pins from the appropriate grille into the rubber

cups in each woofer’s trim panel, as shown with the right side grille
in Figure 5.

ENGLISH

Figure 5.

INFINITY PRELUDE FORTY

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