Guidelines For Use - Voice Systems Sub VS8 Bedienungsanleitung

Active Processed Aggressive Sub Woofer
The acoustic characteristics of the room in which a sound system is used have effects on the overall sound produced,
sometimes with a very significant incidence. In an ordinary sound system, the sub-woofer is used together with other
speakers which reproduce the higher frequencies. Following a few simple guidelines during installation can help to
optimise your sound system's overall performance and prevent some typical problems.
Remember that placing the speakers on the floor, in the corners of a room, against a wall or even in a niche
increases the low frequencies. It is important to remember that you should always proceed with caution, and
these tactics should be used carefully and in a controlled way: otherwise, you may obtain undesirable effects,
such as redundant or blurred sounds (especially with speakers which reproduce the entire audio range). However,
these phenomena may be used to advantage to further reinforce your sub-woofer, increasing its "thrust" within
certain predictable limits:
1) If you place the sub-woofer on the floor:
- the floor becomes virtually part of the horn;
- there is a slight increase in sound pressure, of a +3dB.
2) If you place the sub-woofer on the floor close to a wall:
- the floor and the wall become virtually parts of the horn;
- there is a moderate increase in sound pressure, of a +6dB.
3) If you place the sub-woofer on the floor close to the corner of the room:
- the floor and both walls become virtually parts of the horn;
- there is a good increase in sound pressure, of a +9dB.
Remember that placing the speakers straight on a stage, a floating floor or any other support with cavities
may cause resonances that alter and interfere with the overall sound.
N.B.: solid supports should always be used when possible: with ordinary speakers (but not with sub-woofers)
speaker stands can be very useful.
Remember that high frequencies have a high level of directivity and a very high absorption coefficient;
this means any obstacles between the point of emission and the listener will affect them considerably.
Therefore, to guarantee that medium-high range signals reach the listener in an intelligible form, position
speakers so that they are in a direct line with the audience (clearly visible) about ½ metre / 1 metre above
the audience's heads.
Lower frequencies, on the other hand, are propagated more easily even in the most difficult conditions, and a
number of physical phenomena may also be used for additional assistance (see above). For good low range
sound, if possible place the sub-woofer on the ground or on a very low support, or on the same level as the
audience (speaker stands or excessively high positions are not recommended).
In buildings with a lot of reverberation (places of worship, gymnasiums, etc.) first of all keep the sound
reflections down using materials which absorb sound (carpets, curtains, special panels, etc.). If this is not
possible or is not sufficient, do not simply turn up the volume, because this will also increase the volume
of the reflected sound, and may make the situation even worse. The best solution is to use more speakers,
placed around the room and closer to the audience (e.g. front+back; front+sides; front+sides+back).
N.B.: in these circumstances it may prove necessary to use a delay processor to realign the timing of the
sound of the various speakers (i.e. to overcome the delays caused by the sound propagation time),
ensuring that the sound heard by the audience will be free from "echo".
Example: since the speed of sound is about 344 metres a second, sound takes about 1/10 of a second to
travel 30 metres. Therefore, a listener close to a "back" speaker 30 metres from the "front" speaker would
hear the sound from the "back" speaker about 1/10 of a second before the sound from the "front" speaker:
in other words, he would hear two identical sounds 1/10 of a second apart. So to ensure that the two
sounds strike the ear of this specific listener at exactly the same time, the sound of the "back" speaker will
have to be delayed by 1/10 of a second using a delay processor.

Guidelines for Use

Sub VS8
9