Acoustic Treatment Design for a High End Audio Retail Store

by Nyal Mellor March 29, 2015

Customer Profile

The client was Music Lovers, a high-end audio store with two locations in San Francisco and Berkeley, CA. We worked with the manager of the SF store.

Project Overview

Acoustic Frontiers were asked by Music Lovers to assist with their main stereo listening room in the San Francisco store.

• The room is stoutly constructed in order provide sound isolation. Above the store are residential apartments and the store fronts onto a busy street.
• It has a spacious feel with high ceilings. Dimensions are 15'3" x 22'3" x 9'11".
• The right side wall is floor-to-ceiling glass windows.

Because of the excellent sound isolation the interior acoustics were "challenging". In particular the room had a number of audible and measurable bass issues due the stiff walls. To provide high frequency damping thin drapes had been added in many locations.

 "Before" pictures of the room. Note the thin drapes and lack of any other acoustic treatment.[/caption]

Acoustic Frontiers Solutions

We followed our well honed Room Acoustic Analysis and Acoustic Treatment Design process. The first step was to visit the room to take measurements of the room using our laptop based acoustic measurement system and calibrated microphone. After we'd measured the room came root cause analysis - in other words identifying the acoustical causes of the issues we were seeing in the measurements. The key issues we found were:

• Peak in the frequency response and ringing in the time domain (slow decaying sound) due to coincident room mode resonances at 75Hz (2nd axial width mode and 3rd axial length mode).
• Unbalanced reverberation time due to the use of the green drapes which only absorbed the highest frequencies.

We developed a basic Acoustic Treatment Design using RPG Absorber panels on the ceiling, BAD panels on stands on the side walls and RealTraps MondoTraps stacked in the front corners. We would have liked to go further but were constrained by budget.

The Results

The chart below shows the reverberation time before and after treatment. It is clear that the removal of the thin drapes and its replacement with proper acoustic treatment helped to restore a more balanced high frequency decay profile.

Reverberation time before (red) and after (black) acoustic treatment[/caption]   The spectrogram showed some improvement but additional acoustic treatment via tuned traps would have been necessary to properly solve the 75Hz resonance. View towards the front of the acoustically treated room Immediate and opposite lateral reflection point treatment using RPG BAD panels on RealTraps stands[/caption]   Despite the project constraints the client was thrilled with the results!

In the Client's Words

"Music Lovers has been a leader in high-end audio and video sales and service for over 20 years. In our business it is crucial for us to have great sounding rooms. Before Nyal from Acoustic Frontiers' recommended changes for acoustic room treatments were implemented, our room had several issues across a wide range of frequencies and often overloaded. Once his solution was in place, our room has never sounded better and is now able to achieve a level of clarity, focus and depth that was previously unattainable. In addition to being extremely thorough, Nyal was very easy to work with and continued to provide us with support and recommendations on how to further improve our room. We have since recommended Nyal and Acoustic Frontiers to many of our clients who are in need of room measurements and/or treatment solutions." Josh, Store Manager, Music Lovers Audio.

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