At DGTL Festival 2025, held at NDSM in Amsterdam, the goal was clear: deliver the best possible sound experience for the audience, while keeping impact to the surrounding neighbourhood to an absolute minimum. With the local area becoming increasingly residential, the challenge of delivering an unforgettable audio experience while respecting strict environmental noise standards has never been greater. For environmental noise specialist Ron Westerveld, the solution lies in meticulous planning, transparent communication and trusted technical partners - among them, Funktion-One rental partner Think! AV.

“As a noise consultant for DGTL, I am responsible for drawing up a noise forecast for the permit application,” explains Ron. Using a 3D acoustic model built in GeoMilieu - validated over the past decade through continuous monitoring - he can simulate and refine the festival’s sound footprint well before the first speaker is switched on.

Ron’s model is backed up by real-time data throughout the event. “We provide the sound monitoring using a MeTrao type 1 network. It’s a continuously recording measuring system, which provides and stores LAeq, LCeq and spectral information. By means of special correlation software, it can be seen at any time exactly what percentage of which frequency at a measuring point is coming from which stage.”

In short: total visibility and full control - both increasingly important as the Amsterdam cityscape continues to evolve. “This location is becoming more critical every year in terms of noise due to the advancing housing construction - mainly high residential towers with an unobstructed sound path from NDSM,” says Ron.

The main stage is now just 150 metres from the nearest tower block, with this gap expected to shrink to 125 metres by 2027. Add to that a stricter 80 dB(C) limit on Sundays - 5dB less than Saturday - and the constraints become clearer still. Compounding the complexity this year was the unavailability of a key indoor venue, forcing the addition of a new area on the exposed ‘X-slope’. “It’s the most critical spot on the site,” says Ron.

To succeed under such circumstances, audio must lead the production design and planning. “The stage design is normally not made on the basis of the audio,” Ron reflects. “At DGTL this year, audio led for the first time.”

During pre-production, the Think! AV team used Funktion-One’s Projection software to model sound levels, accurately predict sub array behaviour and determine the precise placement of delay speakers for each stage.

This meant sub-arrays were positioned for the best result, not compromised for aesthetic or other reasons. “Interrupting a sub-array with stairs and other objects between or behind the subs was prohibited during these editions,” notes Ron. Delay systems were deployed across major stages and absorbent cloths used strategically to improve acoustic performance. One of the team’s key techniques is dynamic sliding: lowering levels in one area when the audience shifts to another stage, especially for major headliners. 

Of course, the sound system has a crucial part to play. Funktion-One designs its loudspeakers to have extremely accurate and consistent dispersion patterns. This precision means sound energy is directed exactly where it’s needed - on the audience - minimising unwanted reflections and spill to other areas. “Over the past 20 years, I have had very good experiences with the Funktion-One systems,” says Ron. “The Funktion-One systems are excellently suited to the strict regulations in the Netherlands in terms of noise control.”

That control is maximised by the skilled team at Think! AV. “All FOH techs are aware of the fact that the event is bigger than their particular area. The success of sound control depends on the collaboration of all parties,” Ron concludes. “Think AV is, in my opinion, an example of how it can be done. They are one of our favourite partners to work with.”