Cabinet Finish; Dual Concentric Driver Removal; Drive Unit Servicing - Tannoy System 1000 User Manual

the frequency range where the different drivers overlap, especially on off-axis
response and on spatial dispersion. Actually, because of the detrimental effects
resulting from the fact that they are non-coincident, the drivers should ideally work in
completely split ranges of frequency. High order low and hi-pass filters are therefore
required to reduce the overlap range. Apart from the fact that it makes the design
more complex, requires more accurate components and increases the costs, a major
drawback is that higher order filters involve increased phase and group delay
distortion, which can be quite perceptible. On the other hand the low order filter used
with Dual Concentric drivers achieve a smooth phase response.
The integration of all the features described above is what makes the whole
loudspeaker system even greater than the sum of the individual parts.
SERVICING

Cabinet finish.

To remove marks and scuffs use a medium soft brush. If necessary, a little warm
water and detergent can be used but under no circumstances use a solvent or
abrasive cleaner. The surface will change colour when wet but will return to normal
when dry. For touch-up of paint chips contact your local Tannoy service agent for
materials and guidance.

Dual Concentric driver removal.

Lay the cabinet on its back. Remove the four hexagonal bolts and set aside. Ease
the driver from the front of the cabinet taking care not to mark the front surface.
Use a piece of stout cardboard to lever against if necessary. Remove the driver, note
the polarity of the internal connections and disconnect the internal wiring. Take care
not to damage the moving parts of the LF driver.
To refit the driver, connect the cables from the crossover to the LF and HF terminals.
Fit the driver into mounting hole, making sure that the internal connecting cables are
not trapped between the HF unit and the cabinet crossbrace. Fasten the bolts finger
tight and then progressively torque them down.

Drive unit servicing.

The HF unit may be fitted with a new diaphragm assembly or replaced as a complete
assembly for speed. In either case, with the driver face down, release the three bolts
securing the HF assembly and lift the HF unit vertically upwards and away from
magnetic attraction caused by the LF magnet. Replace the diaphragm - it is self-
centring - or the complete unit, taking care to align the parts correctly.
To refit the HF unit, hold it about 300 mm vertically above the LF magnet in both
hands while resting on your elbows. Slide your elbows apart and lower the HF unit
onto the back of the LF magnet. As the HF unit gets close to the magnet you will feel
the magnetic fields repelling. Align the fixing holes and secure with the bolts,
tightening down evenly. Do not tighten the bolts finally until you are sure the HF unit
is seated correctly and the two magnet systems appear parallel.
The LF unit may be re-coned in the normal way. Ease the trim ring from the rubber
surround and remember to refit it. The trim ring forms an integral part of the HF
dispersion system. Use only the parts and adhesive supplied in the re-cone kit.