Selection Of Operating Mode - Tannoy VLS 7 Operation Manual

4. Selection of operating mode

4. Selection of operating mode
All VLS Series models can be operated as either a low-impedance loudspeaker or within a 70/100 V distributed
system. The operation mode is selectable via a single switch located on the rear of the cabinet.
Low-impedance mode is recommended if the cable runs are relatively short and the number of speakers is
small. If, on the other hand, the cable runs are long and more than a few loudspeakers are required, then a
distributed line system is ideal.
When operating in low-impedance mode, the loudspeaker is able to deliver a wider frequency and dynamic
range. However, if the cable runs are excessively long, then the sound quality may be compromised due to
the increase in cable resistance and the resulting power losses. To keep the load to the amplifier manageable,
it is also recommended that a small number of speakers be used, thus avoiding complex series/parallel
combinations.
When a large number of speakers are installed over long cable runs, it is recommended that a distributed
(70/100 V) system be used. For distributed line, the cable need not have as large a cross sectional area as
for low-impedance, resulting in savings in cable cost. All speakers are placed in parallel with the output of the
amplifier, allowing easy installation. The wattage tappings can be individually adjusted, giving more flexibility
within an installation.
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VLS Series Operation Manual rev 1.1.0