If you’ve ever been to a festival or gig where the sound varied in quality depending on where you stood, or you couldn’t hear the vocals, or the bass rumbled too much or didn’t travel across the room, then the organisers should have hired someone like Abe Scheele.
He has made it his business to calibrate sound systems so they operate at their peak, taking into account the acoustics of a space.
A sound engineer by trade, Scheele first noticed how the environment and the acoustics in different rooms affected the sound when he was touring with a band. He would do his job to the best of his ability each night, but ultimately, the room dictated the outcome. Scheele did a post-grad with the Institute of Acoustics in Trinity College Dublin, to learn about the physics of sound, so he could address the problem.
He calls the process of sound system design "one part physics, one part art" and has some novelty items at his disposal to achieve his results, as he explained around his recent sound system design for Music for 18 Machines gig in St Patrick's Cathedral for St Patrick's Festival.
The event took Steve Reich's Music For 18 Musicians and applied it to synthesisers for a performance in the high-ceiling space built more than 800 years ago.
“Everyone said to me that the acoustics must have been great there, but they’re great in one spot and beyond that, not so much,” says Scheele. “It’s a massive room. You can produce a sound that’s really good in the first 15m but once you get to 30m away, it sounds unrecognisable – you’d never think you were listening to the same thing.”
Audio map
Scheele started to map out the surfaces of the room to figure out how he could achieve the best sound. The first thing he did was pop some balloons and record the response. “A balloon makes an instant sound that goes in every direction equally so any sound that you record after the balloon pops is all in the room.
“Based on that, I was able to work out how far away from the particular speakers we use would it sound okay. So we looked for speakers that were more focused in one direction and wouldn’t add more sound in the room where they shouldn’t.”
Scheele describes sound with four properties: time, frequency, amplitude and distortion. You may have heard the results of him tinkering with those four properties at festivals such as Life Festival, AVA, Body&Soul and Boxed Off.
Scheele mostly works with the secondary stages, where there’s more room to try out different techniques to the main outdoor stages – which utilise the industry standard of a line-array sound system, hanging from each side, with a line of subwoofers across the front or to the side. Scheele says his job title isn’t understood by many, as it’s not as common as perhaps it should be. His job is to make sure that what the sound engineer hears (the calibrated sound) is also heard in every other vantage point.
Active Noise Control
As an example of what Scheele would do in a large environment, consider the issue of concerts disturbing local residents. Scheele employs Active Noise Control to address the sound travelling beyond where it needs to be. It works like this: “If you have one sound and it’s travelling in one direction and you can put another speaker with the same sound and just flip the waveform upside down, they will cancel each other out,” he explains.
At the first year of the AVA festival in Belfast, organisers wanted to utilise the speaker capacity, but there were complaints about bass by residents nearby. When Scheele got involved the following year, he put Active Noise Control in place to address the problem.
“The only thing we can do is to limit the sound that travels outside. The subs at the front were designed so they would only be going forward in the direction of the audience, so we put a ring of subwoofers around the back of the audience that cancelled the front speakers out. I’ve been told they haven’t had any noise complaints since, where other festivals there have had 40 or 50 noise complaints, so it seems to be working.”
Hang Dai
In terms of indoor spaces, Scheele was involved in the acoustic set-up of the Dublin Chinese restaurant Hang Dai. The restaurateurs were aiming for the best sound system they could find in a noisy restaurant environment and Scheele suggested that rather than turning the system up, they turn the noise of the patrons down.
“So that meant a lot of absorption material. If there wasn’t sound bouncing off the walls and the ceiling, then the amount of sound created by cutlery and people would be a lot lower. That means we can have the same sound system running at a level that isn’t obnoxious and sounds clear.”
The ceiling was entirely acoustically treated, foam in the thick tables absorbed sound and teak and cedar were used in the furnishings as they absorb sound well. The result is one of the nicest-sounding restaurant experiences (and clubs) in Ireland.
Large subwoofer
Scheele’s quest to improve sound, along with regular partners such as Hertz-U Soundsystem (which instals Funktion-One sound systems), has lead to the development of a “bass horn”, a large subwoofer that takes a third of the power of a normal one and has more control in terms of where the sound travels. They’ve also utilised “beam steering” in a Funktion-One hang that controls the direction of the upper bass so that it’s more evenly felt by the audience.
But for Scheele, when he tells people what he does, they inevitably ask: ‘Is in front of the sound engineer the best place to stand at a concert?’
“That depends on how good the sound system is set up. If it’s set up properly, you should be able to stand everywhere, but there are limits to what we can do with physics. Unfortunately.”
For more, see Abe Scheele's Facebook page
