Start by standing a few metres in front of the mix position, writes Dave Robinson. Then - careful not to trip over any Belgian music fans - move back a few metres. And then a few more. The sound pressure level remains consistent as you travel. Impressive.
By the stalls selling mementos and jewellery at the back of the square, the SPL starts to drop. As you step over the tram tracks which define the perimeter of the plaats, it drops away considerably. Just like Martyn 'Ferrit' Rowe said it would in his earlier presentation. Very impressive indeed.
People are dining on this side of the rails, supping their potent Belgian beer and chatting away… while a bloody great Amnesty gig rolls on a few dozen metres away. What's more, there are four-storey, flat-faced, acoustically-nightmarish townhouses enclosing the square - but there's absolutely no slapback to be heard.
This is not normal. This is NOT normal.
And so it was that Martin Audio debuted its MLA (Multicellular Loudspeaker Array) in an outdoor, 'festival-style' setting at the Amnesty International concert on 12 May at Antwerp's Groenplaats. The much-anticipated technology - showcased to a select audience of industry pros at Prolight + Sound (see PSNE May) - has been used a couple of times in anger already this year, for hardcore rockers Enter Shikari and German hip hop act Fettes Brot. But the Antwerp Amnesty event presents another set of challenges.
Hosted by Phlippo Audio for the last ten years, the festival brings a crate of Belgian talent right into the heart of the town - where overspill and noise restrictions are keenly monitored. What better environment to test out the power and control of the system?
“What the [FOH] engineer hears is translated throughout the entire audience,” Ferrit tells PSNE during the event. “With our numerical optimisation process, we are calculating the contribution from every single driver and coming up with the optimum magnitude and phase response, across the entire frequency response, for every point in the audience.”
Earlier, Ferrit demonstrated how, not unlike acoustic modelling packages, an MLA user can plug the dimensions of a performance space into the DISPLAY II control software. Then sophisticated DSP manipulation combined with FIR filtering (Ferrit: “Some very, very clever software and the crunching of some very big numbers”) directs the 'cells' of the MLA to produce consistent, wide-band, full-frequency range coverage throughout the designated space. This includes 'containing' the sound too, as demonstrated by the dramatic SPL drop-off at the periphery of the Groenplaats.
Why has no other manufacturer produced a system with such control of magnitude and phase before?
“There's a commercial side and a technology side,” says Jason Baird, Martin Audio's director of R&D. “For the technology, no one has understood the problem in the same way that we have, and how to realise that in terms of the hardware and software.
“And the commercial side is, no one's had the guts to make the investment and say 'we can do this'. As [the Martin Audio] engineering department, we have had to go out on a limb and deliver on every single aspect, in order to create the product. The experience we've had in terms of what we've done - all the promises that we made in terms of how you can control the sound - we've proved that we can deliver."
Rob Lingfield, an integral part of driving the development of the MLA while he was sales and marketing director at Martin Audio, was also in Antwerp. “If you're not privileged enough to be within a certain 'square metreage' of the mix position, you are always going to get a lesser experience. To make something that was 'audience-centric' rather than speaker-centric, that's what I wanted - or I felt this system had to be. Martin Audio have always made acoustically correct boxes: but this was our opportunity to be ground-breaking, as opposed to producing exceedingly good boxes that would compete with anything else out there.
“Meyer had their MILO and MICA, d&b had their J series, Christian Heil had his K,” continues Lingfield. “But each of those are incremental steps forward. If we were going to do anything at all, it had to be a quantum leap. And that's what we think we've achieved.
“So far, in all the tests we've conducted, the system has not only lived up to our expectations, but it has exceeded them. Our goal was to come up with a system that would come up to +/-1dB [within the designated area of coverage] and what we've actually achieved to date is +/-0.5dB”
A final approval comes from Stevan Kemland, Ampco Belgium sales manager, who engineered three acts at the Amnesty Festival, acted as system tech and set the loudness levels.
“At the mix position we are 96, 97dB. You can hear it drop off six or 7dB by the stalls at the back,” he confirms. Kelman says that at previous festivals, the SPL has been only 92dB at the stage in order to keep levels at the perimeter to 90. With the MLA, he expects to be able to push it to 102dB SPL by the end of the night, without upsetting the authorities.
“I was there with the police earlier who were standing at the back looking at their measurements, and saying '98dB there, 90dB here. This isn't normal! This isn't normal!'”
I'm with the cops on this one.