When operating the loudspeakers in normal wiring mode, it is important that the two
gold-plated links are properly tightened to ensure a perfect electrical connection
between LF and HF terminals.
The types of cable used to connect the speakers to the power amplifier will
marginally affect the sound. The cross-sectional area of the cable should be large
enough so as not to affect the damping factor, and generally a cable with a cross-
sectional area of 2.5 mm² or greater is recommended.
Before connecting the amplifier and the monitors, it is advisable to ensure that there
is no signal present either by turning amplifiers gain down or by lowering the output
faders.
Power amplifiers.
The power amplifier should be reasonably well matched in power to the rating of the
speakers. A recommended range of power can be found in the specifications (at the
end of this manual). The use of a powerful amplifier (i.e. the higher figure of the
specified power range) provides headroom which is useful especially for highly
dynamic programme materials.
Because of the high peak power handling of the Tannoy monitors, responsible use of
even more powerful amplifiers should not represent a danger for the speakers if the
amplifiers are not overdriven.
SYSTEM DESCRIPTION AND PHILOSOPHY
A loudspeaker design naturally divides into various parts: cabinet, drive unit(s) and
crossover. The design of these parts cannot take place in isolation as they are all
interdependent.
Drive unit.
The drive unit used in the System 1200 monitors is part of the latest generation of
Dual Concentric units designed by Tannoy. Among many others features, this range
of drivers incorporate a dual magnet assembly, ‘tulip’ HF waveguide and injection
moulded polypropylene LF cone.
The design of the HF waveguide has been arrived at by making extensive use of
CAD (computer aided design). It matches the acoustic source impedance at the HF
diaphragm into the acoustic environment, shaping the wavefront as it travels down
from the diaphragm ensuring equal path lengths to achieve a spherical wavefront.
Wavefront shaping begins at the diaphragm surface and, because the compression
ratio can be kept relatively low with this design, the distortions due to air non-
linearities are minimised. A hyperbolic flare has been chosen for optimum low
frequency performance at the crossover point.
The HF diaphragm is made from aluminium and magnesium alloy, with optimised
shape and thickness providing rigid piston behaviour up to 25 kHz. The diaphragm
assembly is suspended by a precision moulded, inert nitrile rubber surround. Its very
narrow roll eliminates resonances below 25 kHz and provides a very stable and
consistent mounting. The roll form ensures high excursions can take place if
necessary yet provides a fatigue-indestructible assembly.
The HF voice coil assembly incorporates a high temperature copper wire chemically
bonded onto a kapton former fitting onto the outside of the HF diaphragm skirt. The
thermal power handling of the voice coil is greatly increased thanks to its ferrofluid
filled magnetic gap.
