Utilising sophisticated formulas devised by engineers at our Research and Development Facility, the calculator helps installers determine which induction loop amplifier and cable they should use to create a BS7594 (2011) compliant AFILS installation.
The calculator is compatible with any Mac or PC computer running Microsoft Excel and is designed to work in five easy steps:
1) Enter the room length and width on the spreadsheet
2) Select/alter the number of turns in your loop (extra turns can provide increased field strength in smaller rooms and rooms with excessive ferrous metal content)
3) Select the reference level (normally -3dB but this can be reduced to -6dB - see BS7594:2011 Section 3, Table 1 Field variation in the useful magnetic field volume)
4) Set the height of measurement in metres from the plane of loop. This would be 0 if the listener is directly in line with the loop cable, approx. 1.8 for loops laid on the floor or 1.5 for ceiling mounted loops (adjust these measurements based on the actual ceiling height and typical listening height of the user)
5) Consult the wire dependent loop choice box on the spreadsheet to see exactly which amplifier and loop cable best suits your application
Says Tremayne Crossley, SigNET’s Field Sales Manager: "Our new AFILS calculator is a brilliant invention that will save you so much time and effort. The feedback I’ve had from customers who’ve trialled the software has been excellent - the overwhelming verdict is that it makes planning an installation so much easier”.
IMPORTANT NOTES:
• The calculator assumes a perimeter loop is being installed in a room with very little metal content (i.e. a square or rectangular loop that is being run around the edge of the covered area).
• Although the amplifier recommended by the calculator WILL generate the required magnetic field it is the responsibility of the designer/installer to ensure the amplifier has the required inputs and features pertinent to the job in hand.
• It should be noted that steel reinforced flooring and/or roofing can considerably attenuate the field strength of the completed system - if in doubt, refer to our AFILS guide for further information.
• Prior to installation we always recommend a trial loop is run around the covered area and that the system is tested to ensure correct operation using one of our FPROK1 test kits which includes a handheld magnetic field strength meter and a handheld signal generator (c/w test tones and headphones).
Click Here to Download our Induction Loop Calculator V1.3
The legendary set in Leavesden now plays host to the “Harry Potter Studio Tour”, a magical three-hour behind the scenes walk around the wonders of one of the most famous and successful film series of all time. Two of SigNET’s PDA1000/2 and three PDA500/2 induction loop amplifiers are in operation to ensure that the tour, which includes the actual Great Hall of Hogwarts School and the treasures of Headmaster Dumbledore’s office, is accessible to the hard of hearing.
Top audio-installation company, Clarity UK, employed some acoustic wizardry using designs drawn up by SigNET’s induction loop expert, Tremayne Crossley. SigNET’s APSS Phase Shifter was utilized to combat overspill from the loop (so people with hearing aids outside a room cannot pick up conversation) and to ensure consistent coverage throughout the site thus avoiding those dreaded ‘dead spots’ (the areas directly above or below the loop cable where the signal suddenly drops to zero and cuts out sound altogether).
Said Giles Palmer of Clarity: “By taking the signal from the studio’s in-house audio system, the APSS produces two signals 90 degrees out of phase with each other. These signals are fed into two identical loop amplifiers, which are, in turn, connected to two loops laid out in a special overlapping pattern. As a result, the magnetic field is evenly spread within the covered area but the strength falls off much more quickly than normal outside the loop thus minimising overspill.”
When it came to installing induction loop cable in the Great Hall, Clarity needed to take into consideration the effects of the genuine York-stone floor.
Explains Giles: “Normally flooring does not pose a problem when installing induction loop cable but the heavy stone in the Great Hall complicated matters as it threatened to crush the cable. The solution was to specify a specially tough cable and house it within three layers of insulating material.”
For more information, contact SigNET on 0844 800 1625 or visit www.signet-ac.co.uk
Trading at just £160.24, the new FPROSG Audio Signal Generator makes testing induction loop systems to current British standards simplicity itself.
Factory calibrated to provide a fixed audio signal, the generator includes all of the test tones required to test an AFILS to BS 7594 (1 kHz sine wave, frequency response and metal compensation), plus speech and music tracks to assist with subjective testing.
Says Tremayne Crossley, SigNET’s Field Sales Manager: “This innovative new product is a welcome and very cost-effective addition to SigNET’s testing equipment range. Specifically designed to simplify the testing of induction loop systems, the FPROSG, used in conjunction with our existing Fosmeter Pro Magnetic Field Strength Meter, produces good consistent results every time”.
Specifically designed for use in overseas applications where ‘Type A’-style portable handsets and jack plate combinations are accepted by prevailing standards, the EVC301/JP Jack plate and the EVC301/PH portable handset trade at just £96.37 and £25.70 respectively.
Multiple Jack plates featuring a quarter inch jack socket can be connected to a single SigTEL line in a stairwell or riser. In the event of an emergency, a marshal or fire officer can plug their portable handset into the jack plate to open up a speech channel with the main SigTEL controller.
Said Charlotte Manley, SigNET’s Sales Director: “As an increasing number of overseas fire telephone specifications now call for roaming handsets, these new products look certain to be a huge success in the Far and Middle East. However, it is important to note that UK standard BS5839-9 does not allow for their use.”
