Clay Center for the Arts & Sciences in Charleston, West Virginia is unusual in that it promotes the performing arts, visual arts and sciences all under one roof. A key facility is the Caperton Planetarium & Theater, where a major refurbishment has seen an Alcons Audio pro-ribbon sound reinforcement system installed.

The venue presents planetarium shows and large-format films on a giant domed, perforated metal screen. Over recent years it has been extensively refurbished with full digital audio/visual facilities, which now includes the installation of the Alcons Audio system.

MediaMerge Inc based in Chelsea, Alabama, was tasked with specifying and installing the new equipment: ‘It is vital that dome cinemas can differentiate their experience from the flat screen down the street, but they offer considerable and unique challenges to system designers,’ says MediaMerge owner, Tim Ogletree. ‘The old audio system never really achieved what is expected by modern audiences, so we wanted to fix all the coverage and quality issues to give them an exceptional experience.’

To cover the audience properly in a dome cinema, loudspeakers need to fire through the perforated screen from unique locations, which is very different to the positioning of speakers in a flat screen cinema. To achieve this, Ogletree used an audio specification based on the Alcons CRA24 Cinemarray Scalable Medium-Format Line Source Screen System. Five clusters of two units – each with a CRA24N standard dispersion unit and a CRA24W wide dispersion unit – plus a centre cluster of two CRA24WX wide dispersion units arrayed around the dome.

Four floor-mounted CB362, twin 18-inch excursion driver subwoofers completed the system, all powered and controlled by Sentinel10 four-channel amplified loudspeaker controllers.

‘The ability to customise coverage and throw in a dome cinema is vital. The distances from loudspeaker arrays can vary wildly and fixed coverage solutions always mean compromise,’ Ogletree says. ‘We had modelled the system and felt that the CRA24 would work really well in terms of quality, power and audience coverage. It allows you to create building blocks to satisfy whatever the venue needs, which is a massive benefit over conventional systems.

‘Another unique challenge of dome cinemas is that, by their nature, there is a very limited space in which to install the loudspeakers behind the screen and the rigging does not hang vertically, he continues. ‘The CRA24 was a lot more compact, lighter and the rigging simpler and more versatile than conventional systems.’ Once the system was installed, commissioning specialist Phillip Peglow from sound design and consulting firm Broken Chord was brought in to help tune it.

‘Because the design was rock-solid, it was simply a matter of shaping the performance response of the system to the required standards,’ he adds. ‘With horn-loaded loudspeakers behind any type of screen, sound bounces off the back of it, creating distortion. The Alcons pro-ribbon speakers have nowhere near the amount of audible and measurable distortion of traditional speakers, while the performance of the subwoofer arrays exceeded my expectations.

‘I was very pleased with the performance of the Alcons system in a challenging acoustic environment and would recommend Alcons for both cinema and multipurpose use without hesitation. It was my first time specifying Alcons, but I will be looking to their systems in the future. I’m definitely a fan.’