Why choosing the right speaker cable is crucial in high-end cinema installs27 November 2015
Ron Lagerlof of Hollywood-based Visioneering Design has specified Sommer Cable for all his company’s installations of Meyer Sound cinema systems, which feature powered surround speakers with IntelligentDC technology, and Dolby Atmos surround sound.
With IntelligentDC technology, Lagerlof (left of picture) explained, “Each speaker has its own built-in amplifier, but unlike most other self-powered speakers that need 110 line voltage from the wall, these speakers take 48V from an external power supply.
“It is very important with this IntelligentDC system to have a cable that is able to get power and audio in the same jacket and not have interference from the voltage side into the audio side. Sommer Cable has been making cable for a number of years that does this, and it’s similar to a cable that’s used a lot in lighting or control systems, but it has a heavier gauge power conductor.”
A recent application included Meyer Sound MINA line array loudspeakers at the new 4K cinema in the former Jay Leno Stage in Burbank.
Lagerlof explained: “Our challenge on this project was to install a cinema experience in a large live venue in a former soundstage. The specification was to be Dolby Atmos 4K/3D, with full-blown projection suitable for premieres and red carpet showings. I spent time with David Gray of Dolby to figure out the best way to cover this very large room. Dolby had a lot of experience with large rooms and in particular live venue type rooms like the Dolby Theatre in Hollywood. I’ve done quite a number of theatres and screening rooms with Meyer Sound, but it was pretty obvious that we weren’t going to be able to do the standard theatrical installation.”
Lagerlof next visited Meyer Sound headquarters in Berkeley, California, where different monitoring schemes were discussed. “What we landed on was MINA line arrays with the new Meyer HMS-12 and HMS-15 surround loudspeakers, fully capable of producing enough sound pressure level in a venue of this size.”
The Meyer Sound line arrays are configured as five screen channels: left, centre, right, left extra and right extra, situated behind the largest roll-down screen that Stewart Filmscreen has built to date, with a 14m wide by 8m tall viewing area. The MINA line arrays are separate from the sound system installed specifically for live performance. The cinema loudspeakers are behind a permanent scrim upstage, mounted on chain motor hoists so that they can be lowered for service.
Sommer’s Monolith Power/DMX cable is shielded by a tinned helical copper mesh. Both the power cable and the balanced pairs have their own jackets for extra safety and easy wiring for DMX controlled lights, powered speakers, and other devices that require power and analogue or digital audio feeds. Sommer’s Kolorith cable was specially designed to fit the EN3 Switchcraft connector for the IntelligentDC technology loudspeaker series from Meyer Sound, transmitting audio and power in one cable. The Meyer Sound MPS-488HP IntelligentDC power supplies are more than 50m from the speakers and the heavier-gauge Sommer cable allows for the longer runs necessary, with enough power to handle the Atmos peak levels.
On this project, as with many others, Lagerlof worked with Andy Potvin (right of picture), senior staff engineer with Dolby Laboratories. Additionally, Steve Bush from Meyer Sound visited the site to commission the line array, which requires specific calibration for each of the individual speakers. The new Burbank theatre line array consists of two low-frequency cabinets and seven cabinets that handle the mid- and high-frequency ranges.
In this particular installation, the Meyer Sound array can hit the height areas on the mezzanine level as well as aiming down towards the seats in the main part of the auditorium. By tweaking the various components in the array, it is possible for all signals to arrive at the same time and at the same SPL to each of the seating areas. More energy is sent to the back of the theatre at the upper range of the mezzanine seats, and then is tapered down to get smooth coverage at lower levels for the seats on the main floor of the theatre.
“It’s a very unusual project, not your typical screening room or theater venue,” commented Lagerlof. “Just the fact that we can roll with a lot of different components in the system tied in with a live performance system as well as the cinema aspect of it really makes it a unique theatre.”