Orienting an Outdoor Amphitheater Surrounded by Natural Rock Formations

Joseph Morris – jmorris@resolutgroup.com
Instagram: @resolutgroup

Resolut Group
181 E 5600 S, Suite 200
Murray, UT, 84123

Popular version of 2pAAa6 – Measurement-informed orientation of an amphitheater surrounded by natural rock formations using in-situ impulse response analysis.
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/planner.php?id=ASASPRING2026

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

A venue’s beauty may draw guests in, but the acoustic experience is what brings them back.

When attending a symphony, the first desired experience is to hear and appreciate music. Musical quality is important for design aspects of an outdoor amphitheater, especially when the design is impacted by large, natural rock formations. Maxwell Park in Hilldale, UT contains several striking, extraordinary features that naturally catch any eye. Although there’s beauty in this scenery, acoustic tests were needed to help enhance the listening experience, i.e., find the best stage direction. Because of these colossal rocks, the way the stage faces can strongly change what the audience hears.

During predesign, two realistic stage orientations were compared: a stage on the north side facing south (Figures 1-3), and a stage on the east side facing west (Figures 4-6). The orientation matters because rocks are reflective and if reflections arrive at the audience at different times and from different directions, they can smear the sound and make music feel less clear. To find the best option, four types of tests were performed at each orientation: an impulse response test (to see when echoes arrive), a “chirp” test (to check how different pitches carry and whether they interfere), a real-time analysis (to see how evenly sound spreads across the audience area), and a music listening test (to hear the real-world result). The client team, including several city officials and the architect, was on-site during testing and though graphs, tables, and data analyses are useful, hearing the difference in-person made the greatest impression.

Aerial view of an outdoor event layout with a marked stage area and audience zone in a desert-like terrain.

Figure 1: Northern Stage Design

Sound level meter mounted on a tripod in a desert clearing with towering red rock cliffs and sparse vegetation under a clear blue sky.

Figure 2: Northern Stage Simulation

Tripod with mounted sound level meter standing on a wide, dry dirt field surrounded by distant rocky hills under a clear blue sky.

Figure 3: Southern Audience Area

Aerial view of an outdoor stage and audience area marked in red near sparse vegetation.

Figure 4: Eastern Stage Design

Tripod-mounted microphone setup on a dirt path with desert shrubs and red rock cliffs in the background under a clear sky.

Figure 5: Eastern Stage Simulation

Wide view of a dirt plain with green shrubs and rugged rocky mountains under a clear blue sky.

Figure 6: Western Audience Area

From the north side, sound struck the nearby eastern rock face almost immediately and provided positive reinforcement for the direct sound. However, the sound reflecting off the western rock face arrived at a significant delay causing negative reinforcement which distorted the overall quality. Those repeated reflections, arriving at slightly different times, blurred the sound, made it harder to tell where the music was originating, and confused listeners. During the music listening test, the clients were so distracted that some initially assumed the sound equipment was the problem, calling it, “low quality”.

On the east side, the audience heard stronger direct sound, with only mild reflections from farther rock formations. Those reflections helped the sound feel full and supportive. During the music listening test, listeners described their experience as clear, impactful, more evenly heard across the area, and emotional to the music that was played. The same equipment and music were used for both orientations, but the natural rock formations from the eastern side had the greatest acoustic impact.

Measurements, figures, and charts help explain why one option performs better, but the shared, real-time listening experience made the difference. Based on that direct experience (supported by test results), the east-side stage orientation was the clear recommendation to, and accepted by, the client.