Important! Please note that the international standard IEC 60118-4 must be fulfilled for hearing loops installed in public venues.
Select an amplifier (amplifiers) based on
- Size of the room (one or several amplifiers)
Does overspill has a negative influence on other areas (standard amplifier or SLS amplifier) Please
read more about Univox SLS here below and see a short presentation at Univox Support (powerpoint file).
Where to place the cable (standard cable or flat copper foil cable)
Cable in the roof or in the floor (If the loop is smaller than 200 m2 the loop can be placed either at floor level or in the ceiling at approx. 2.5m.)
- Heavy metallic influence (standard amplifier or SLS amplifier)
Choose an amplifier with at least 20% margin (sometimes you need even bigger margin) to compensate for metal loss due to reinforcement or other metallic in the environment. Univox amplifiers coverage area are specified to generate the peaks (0 dB and 400 mA/m) specified by the standard. They cannot be compared with amplifiers specified for only 100 mA/m (16 times lower power!)
The amplifier's maximum coverage area is measured in a free field situation. In reality (with metallic objects, like reinforced concrete) the coverage can be reduced by approximately 20-50%.
If you have a square loop, the sides should not exceed 10 m. If they do, you should plan for several loops.
Plan the location for the amplifier (amplifiers). If possible we recommend dividing the area in two or more identical loops. Each loop shall have a twinned (or paired) connection wire.
2 x 2.5 mm2 is the most flexible cable. Using a twin-cable makes it possible to choose between one/two or parallel turn loop configuration and is suitable for most installations. There are no specific demands of isolation of the cables, ordinary speaker cables are excellent. You can also use a flat copper foil cable for venues where it is difficult to install an ordinary cable.
Univox SLS - a summary
Univox® Super Loop System® SLS is a balanced uncorrelated induction loop system. It consists of two separate loop systems (Master and Slave) with a separate current controlled amplifiers connected to each loop. Univox SLS systems have several advantages compared to old conventional loop systems:
- Almost no vertical and horizontal overspill
- Smoother field strength level
- Highly increased frequency response
- Less impact on field strength and high frequency range by reinforcements or other metal construction parts
- Less directional sensitivity (no level drops when tilting the head)
- Increased efficiency due to controlled field strength
- Highly reduced risk for interference with other electronic equipment, guitars, microphones, etc.
There are many possibilities for the layout of the loop wire, but the basic Univox SLS system for most installations is the same: A Master loop which covers the whole listening area and a Slave loop, slightly smaller compared to the Master loop.
See a schematic picture of a Univox SLS installation
The size of the segments controls the overspill, both horizontal (sideways) and vertical (sitting vs. standing). In theatres or cinemas the segment size is simply the same as the distance between the seating rows for ease of installation (with Univox SLS there is no field strength drop above the crossing of the wires). 1 meter segment size is normally fine but other segment sizes could be recommended depending on the installation.
After the installation of wire and loop amplifier, the whole system has to be certified. Both installation and adjustment has to be performed by trained staff equipped with a field strength meter and basic knowledge of how the system works and how loops are measured and adjusted. Contact your distributor for all questions regarding projection, installation and adjustment of the system. You can find more information at:
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