160 Channels of Shure Wireless Microphones used for T-Mobile Flash Mob
Hand Held Audio Ltd, a leading pro-audio hire company, supplied 160 channels of Shure UHF-R wireless microphones for the latest T Mobile flash-mob advert. The karaoke style event was a world first and the largest RF event of its kind ever recorded, which was fully supported by Shure Distribution UK (SDUK).
Lead by international pop/rock star Pink, over 13,000 people descended on London’s Trafalgar Square to sing hits including ‘Hey Jude’ and ‘Is This The Way to Amarillo?’ Members of the crowd were supplied with 160 Shure microphones, including the Beta 58 and SM58 models, each transmitting on independent RF channels. Footage from the event will be used to produce a series of television advertisements for T-Mobile.
Hand Held Audio was responsible for deploying the wireless technology for the event and determined that 160 wireless channels were required to meet the project brief. With such a challenge on their hands, HHA called upon SDUK to assist during planning and to provide additional onsite support throughout the event. The final frequency plan comprised of 162 channels (two extras for Pink) occupying 518Mhz to 865Mhz. Every microphone would need its own independent channel, with all having to run alongside each other simultaneously on the day. Providing coverage for the whole of Trafalgar Square, measuring 100m by 60m, presented a significant challenge. The busy RF environment in Central London and possible inter-modulation between frequencies also compounded the problem of successfully isolating enough frequencies.
Tarkan Akdam, Technical Manager at Hand Held Audio comments, “We decided to use the Shure UHF-R kit as it offered the best in current radio mic technology and frequency ranges needed to make this work. The antenna system, designed to feed the 80 dual receivers, had to have enough gain to provide sufficient levels of coverage but not too much that inter-modulation and RF interference would cause problems. It was a question of getting the balance right. We opted for a four way antenna system, with passive Shure wideband paddles (PA805SWB). I designed and built a four way wideband, low noise, high gain RF headamp system, all interconnected with over 400 meters of double shielded Triax cable.” This ensured voice data from every microphone was picked up, while minimising interference from other RF channels. A second pair of Shure active wideband antennas were installed on the broadcast truck aimed at Pink’s podium to guarantee coverage for her microphone. To properly distribute the RF signal, Tarkan opted for 21 Shure UA845 antenna distribution units.
“Isolating 160 channels is a big task in any location, and being in the centre of London made is an incredibly technical and precise task.” He explains. “We faced several issues. Trafalgar Square is already a busy RF environment, with frequencies in use by local business, TV stations and theatre productions in the nearby West End. We needed to take into account any local TV transmitters so we didn’t interfere with anyone else whilst ensure the singers’ voices came through crisp and clear. Sufficiently strong wireless coverage, to ensure we picked up all the mics was a must.”
Prior to the event, several field strengths tests were conducted to check for interference and make sure all 161 channels would run alongside each other. Akdam comments “We ran tests initially with 40 channels and the day before the event we had 160 running at once. The task was incredibly daunting but on the day it went off without a hitch and we are very pleased with the result. The Shure mics and UHF-R equipment worked superbly, with voices of the singers delivered seamlessly to the receivers. In terms of size, we believe this is a world’s first in RF events.”
Akdam adds “Events of this nature require resources and having fewer things to worry about is always a great help. I knew with Tuomo Tolonen from SDUK I had the full backing of Shure which in turn meant I was lot more positive that we could achieve what we set out to do. Using the knowledge of the application engineers put me in a better position to cross any technical hurdles.”
|PA805||Directional wideband antenna offers 7 dB of gain and 3 dB of beam width.|
|UHF-R||Wireless system masters the high pressure and extreme conditions of any large-scale touring or installation while delivering uncompromising audio.|