Polarity Checking; Amplification & Power Handling; Power Selection (I5T Aw) - Tannoy i5 AW User Manual

4. Pol a rity Checking
It is most important to check the polarity of the wiring. A simple method of doing this
without a pulse based polarity checker for the drive unit is as follows: Connect two
wires to the +
v e
the + terminal of the battery to the speaker cable leg which you believe to be
connected to the red speaker terminal and likewise the -
black speaker terminal.
If you have wired it correctly the drive un it will move forward, indicating the wiring is
correct. All that remains now is to connect the +
the amplifier and the -
moves backwards, the input con nections need to be inverted.
If problems are encountered, inspect the cable wiring in the first instance. It should
also be noted that different amplifier manufacturers utilise different pin configurations
and polarity conventions, if you are using amplifiers from more than one
manufacturer, check the polarity at the amplifiers as well as the loudspeakers.
5. Amplification and Power Handling
As with all professional loudspeaker systems, the power handling is a function of
voice coil thermal capacity. Care should be taken to avoid running the amplifier into
clip (clipping is the end result of overdriving any amplifier). Damage to the
loudspeaker will be sustained if the amplifier is driven into clip for any extended
period of time. Headroom of at least 3dB should be allowed. When evaluating an
amplifier, it is important to take into account its behaviour under low impedance load
conditions. A loudspeaker system is highly reactive and with transient signals it can
require more current than the nominal impe dance would indicate.
Generally a higher power amplifier running free of distortion will do less damage to
the loudspeaker than a lower power amplifier continually clipping. It is also worth
remembering that a high powered amplifier running at less than 9 0% of output power
generally sounds a lot better than a lower power amplifier running at 100%. An
amplifier with insufficient drive capability will not allow the full performance of the
loudspeaker to be realised.
It is important when using different manu facturers amplifiers in a single installation
that the have very closely matched gains, the variation should be less than +/ - 0.5dB.
This precaution is important to the overall system balance when only a single
compressor/limiter or active crossover is bei ng used with multiple cabinets; it is
therefore recommended that the same amplifiers be used throughout.

6. Power Selection (i5T AW)

Determine the maximum power in watts needed at each speaker location. The i5T
AW transformer can be tapped at 30W, 15W, 7.5W and 3.5W via the rotary switch
located at the rear of the loudspeaker, at either 70 or 100-Volt lines. When the
relevant tappings have been selected add the individual wattages required at all
speakers and select an amplifier with a rating equal to or exceeding the total wattage
required. All of the transformer primaries should be connected in parallel to the output
of the amplifier. If for example, you select the 7.5W transformer tap, it means that
at full rated amplifier output the speaker will receive the full 7.5W. If the amplifier
gain is reduced each speaker will receive a proportional amount of power,
maintaining overall system balance.
v e v e
and - terminals of a PP3 battery. Apply the wire that is connected to
v e
lead to the -
v e
v e
speaker lead to the +
v e
terminal on the amplifier. If however the driver
leg of the battery to the
v e
terminal on