Acoustic Room Treatments – The Ammonite Room

Our client tasked us to transform a very reverberant space within an expansive modern home. As shown below, the result was a multi-functional stereo room with a high-end custom audio and interior design solution, featuring acoustic room treatments.

Background

Clean lines distinguish the stunning minimalist home. White interiors and floor-to-ceiling windows on the first and second floors overlook the grounds and a private lake. Due to the building’s open spaces and sparse style, the result was a very reverberant environment. Owing to this, it made the room’s intended purpose as a listening room very challenging.

Acoustics in any entertainment-style space are hugely important. Certainly, even a multimillion-pound system will sound poor in an over-reflecting, reverberating room. In fact, this will be the case, whatever electronic equalization or compensation system is used.

The Room

The room therefore urgently required an acoustic treatment plan. There was an emphasis on minimal design within the home. Therefore, any tech used needed to fit smoothly into the home or be able to stand as a piece of design in its own right. A simple panel treatment – even if designed well – would not be enough. For this reason, the concept: ‘technology meets design’ began to take shape.

Of course, we knew that only a solution of custom, stylish acoustic room treatments would do for the home’s reverberant stereo room. As a result, we opted to install a pair of distinctive grey Bowers & Wilkins Nautilus loudspeakers. In addition to their superb audio quality, the Nautilus loudspeakers exist as a modern work of art. They also represent a large investment for the client.

“We knew that this was a challenging space, with concrete walls, floors, ceilings and lots of glass,” said Guy Singleton. “Hence, controlling acoustics in this kind of space is very challenging; there is no focus or principles that make up good audio. Moreover, no matter how costly loudspeakers are and no matter how much you spend on amps; unless you can control the sound in that room, you’re fighting a losing battle. Thus, you are truly throwing good money away. Our client was keen to listen to music using these superb loudspeakers, so we designed an acoustic treatment solution into this room.”

Acoustic treatment to improve performance of the home cinema or media room.

Technical Solutions

We tested the room’s RT60 (reverberation time), measuring how long it took an impulse to decay over 60dB. Certainly, a good-sounding room will ideally have an RT time of approx half a second, effectively controlling any resonances and reflections. In this case, the RT60 value was measured at an uncomfortable 4.5 seconds, before any tech was applied.

Prior to the acoustic room treatments going in, there was no audio control due to the reflective surfaces; this meant that the Nautilus loudspeakers were bordering on un-listenable.

We consequently designed a custom acoustic solution, befitting of the home’s unique interior, to tackle the stereo room’s acoustic issues. Firstly, we calculated how much absorbent material was needed and determined the best positioning for the acoustic panels. Once certain that the reverberation issues would be rectified by the design, we focussed on the aesthetics.

The stylish blade and panelling designed treatment controls the first reflection point. The result is that this allows the client to comfortably experience the loudspeakers. The reverberation time has also dramatically reduced, as we have redirected back-wall reflection. This avoids the unwanted concentration of sound in the sweet spot / main listening area.

The RT60 value now measures an impressive 0.5 seconds. This is a dramatic improvement when compared to 4.5 seconds before the acoustic treatment. The acoustic panels scatter the high and mid frequencies and absorb the lower frequencies. This has the effect of taming the resonances and first reflections.

Loudspeakers

Two-channel audio is provided by two grey Bowers & Wilkins Nautilus loudspeakers, positioned on the left and right side of the room. On balance, we selected Nautilus for this room, as it represents the pinnacle of design, backed up by engineering excellence.

The Nautilus is made to order in any custom colour. Innovative design, precision manufacturing and exhaustive testing ensure Nautilus performs optimally. Additionally, each unit is hand-built to order by a dedicated specialist team in the manufacturer’s UK factory.

Bowers & Wilkins

Nautilus are quite unlike a conventional box speaker. To package the distinctive tubes for use in the home, the manufacturer developed the striking, space-efficient, spiral form from which the speaker takes its name. Long, tapered damping tubes allow the drive units to work optimally by gently absorbing stray energy whilst effectively reducing resonances.

“They are a perfect example of technology meeting design,” said Guy. “Notably, these are four-way loudspeakers which come with their own external digital crossovers. I’m always excited that we can go to the B&W factory to watch them being made. B&W even hand-deliver them, its quite an event.

A 200W Class-D Classé AMP5 five-channel amplifier powers each loudspeaker. These utilise switching technologies for both power supply and amplification stages, both of which are fed through an eight-channel Sigma SSP MkII preamp/processor.

Reference for audio is considered 105dB; the combination of amplification power and loudspeakers surpass the performance objective, clipping at 106.4.

Acoustic Room Treatment

“We wanted something that matched and complimented the aesthetics of the room. This is where this Ammonite theme evolved from, taking inspiration from the loudspeakers to create one, cohesive, artistic statement,” said Guy Singleton, who was careful to highlight that the solution wasn’t just functional, but selling the concept of a unique, custom, multifunctional piece of art.

It was clear that a custom modular solution would improve the space. Once we were confident that the technology would resolve the issues, we focussed on the aesthetics.

The left and right walls had large gold parametric panels installed. Additionally, installed onto the back wall was a detailed diffractor panel design. These comprised of four different types of timber– two ‘blocks’ on the left, and four to the right. These stylish acoustic room treatments frame the two striking loudspeakers.

Each diffractor panel combats the acoustic waves that hit the back wall of the room. 528 different wooden blades form the finished acoustic interior solution, handcrafted and meticulously slotted together.

Behind the acoustically transparent panels is absorption for the lower frequencies, which are capable of handling frequencies below 500Hz. The intricate back panels effectively scatter the mid and high frequencies, while absorbing the lower frequencies.

“Wavelengths get shorter, as frequencies get higher,” said Guy. “You need this kind of concentric pattern to diffuse and scatter those sounds. Ultimately, you’re absorbing certain sounds, and you’re scattering others.”

In conclusion

The results speak for themselves! In the final analysis, we have reduced the RT60 value from 4.5 seconds to 0.5 seconds, giving the client the ability to use the room for its designed purpose. As has been noted, the room now boasts linear RT60 control over seven octaves, whereas before there was no control over resonance, reverberation and reflection. Correspondingly, the listening room has a noise floor measuring 35dB.

An example of an acoustic analysis.
An example acoustic analysis.

For further reading, here is more information about acoustic room treatments.

If you would like further advice on acoustic treatments, please contact us

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