NEW SOUND MANAGEMENT SYSTEM FOR THE BRIGHTON HILTON METROPOLE

The Hilton Brighton Metropole has installed a new sound system in its conference suite, selecting Allen & Heath’s iDR-8 DSP processor to manage the sound distribution. In addition to the Hotel’s 334 bedrooms, there are 28 meeting and function rooms, and 9 exhibition halls. The increasing popularity of the Hilton for different types of events has meant that the risk of noise disturbing local and hotel residents has also increased. Loading and unloading of vehicles for exhibitions is strictly controlled to certain hours of the day, but evening functions, with either DJ’s or live bands, have caused complaints. Working with Brighton & Hove City Council, Acoustic specialists, 24Acoustics and Big Sky Audio, were appointed to manage the project. 24Acoustics’s principal, Steve Gosling, is quick to point out the complexities of noise problems in a large building like the Hilton: “Immediate solutions can be found for the more obvious noise leakage points, such as poorly fitting doors or air conditioning ducts but much of the problem is structure-borne noise. Complainants can be quite a few floors up the block, but they are directly connected to the hall below by the structure of the building. Our first approach was to measure real events and testing revealed concerns about how different PA systems, coupled with the building structure, attracted complaints but others did not.” Two days of dedicated testing followed with an 8kW professional PA system loaded into the main hall, where the majority of music functions take place. During this testing, multiple locations around the site were visited and noise levels recorded in detail. “Having control of the noise source allows us to measure in significantly greater detail than just listening to random music from a real event,” commented Richard Vivian of Big Sky. “Some bands turn up with two PA speakers and cause a problem, others use a distributed system and don’t. Both may work acceptably in the room where the event is taking place, but will interact in completely different ways with the building structure. We are not just looking at how loud the music system is, but also the frequency content of the noise source and how the system couples with the room.” Following analysis of all this data it was concluded that the only way the hotel could ensure absolute control of the noise within the room was to install a house PA system. This would mean that future calculations for sound isolation within the structure could be based on a known and predictable system with built-in limiting to ensure maximum permissible levels would not be exceeded.

“Some level control systems that simply cut the power off are really quite brutal and should only be used in extreme situations,” commented Vivian. “A house system with a gentle compression that only comes in when it is needed is a far more elegant solution. Not only can we control the maximum level, we control the room interaction - all the speaker positions are fixed and mechanically isolated - and we can be sympathetic to the structure’s behaviour by using subtle EQ that does not detract significantly from the system performance but also does not cause the neighbours to complain.” System installers, Xtreme AV, specified MC² T–Series amplifiers, EV RXH212’s loudspeakers, and an Allen & Heath iDR-8 to provide all system control. Craig Wiggins commented: “There were quite a few options for system control but Allen & Heath just offer so much flexibility in their products that I realised the iDR-8 would not only be more than capable to do what we want right now, but would also offer the opportunity to expand and modify the system in future. The iDR software interface is very intuitive, and the option to dial in and modify system settings from a remote location offers us a really useful facility.” 24Acoustics also specified an upgrade to the acoustic cladding around key structural points in the building. “The installation of a house system with very precise control has meant that amplified music levels are now always predictable and controllable. Individual loudspeaker control through the Allen and Heath iDR-8 has meant that some loudspeakers in locations more sensitive to noise problems can be individually tuned to have a minimal effect on the structure and significantly reduce noise problems elsewhere in the building. The adaptability of this system has proved a massive benefit to achieving high quality sound within the venue yet minimising disturbance elsewhere,” concludes Vivian.