TACOM Detroit Arsenal

Challenge

The TACOM (Tank Automotive Command) Detroit Arsenal facility on Mound Road in Warren, Michigan operates an entry gate where vehicle inspection and security processing generates noise that impacts surrounding properties. Peak noise events from vehicle operations at the gate approach 90 dBA, and the facility needed to reduce noise exposure at nearby receivers to improve community relations and meet operational requirements.

The acoustic challenge was complex: the noise sources were mobile (vehicles moving through the gate area), the gate operations could not be relocated or significantly modified, and the solution needed to provide measurable noise reduction at specific receiver locations without impeding security operations, vehicle flow, or sightlines required for gate function.

Solution

Memtech Acoustics conducted a detailed noise assessment and predictive modeling study using Statistical Energy Analysis (SEA) with Monte Carlo simulation methods. This approach allowed Memtech to model the probability distribution of noise levels at receiver locations under varying operational conditions, rather than relying on single-point deterministic predictions.

The study evaluated multiple barrier configurations in three phases:

Phase 1: Baseline Characterization. Source noise levels, directional characteristics, and temporal patterns were measured at the Mound Road Entry Gate. Receiver locations were established at the property boundaries and nearest noise-sensitive positions. Ambient noise measurements established the existing acoustic environment.

Phase 2: Configuration Modeling. Multiple barrier wall configurations were modeled, including variations in wall height, length, placement, and orientation. A key finding was that a 100-foot south-only barrier wall was insufficient, providing only 4.6 to 5.5 dBA of reduction at the primary receivers. This fell short of the 10 dBA intelligibility target, which represents the threshold at which noise reduction becomes clearly perceptible and meaningfully improves the acoustic environment at the receiver.

Phase 3: Recommended Configuration. The modeling identified a 150-foot bilateral barrier configuration (walls on both sides of the noise path) as the solution that achieved 12 to 14 dBA of predicted reduction at the primary receivers, exceeding the 10 dBA target. The bilateral approach was necessary because single-sided barriers allowed diffracted and reflected sound paths to reach the receivers from the unshielded side.

Memtech also incorporated DART (Defense Automotive Research and Testing) audio simulation into the analysis, allowing stakeholders to audibly preview the predicted noise environment with and without the recommended barriers before committing to construction.

Results

The predictive modeling demonstrated that the 150-foot bilateral barrier configuration would achieve 12 to 14 dBA of noise reduction at the primary receiver locations, exceeding the 10 dBA intelligibility target. The SEA/Monte Carlo methodology provided confidence intervals on the predictions rather than single-point estimates, giving the facility command a clear understanding of expected performance under varying operational conditions. The DART audio simulation allowed decision-makers to experience the predicted improvement before construction, supporting the funding and approval process. The engineering analysis provided the defensible technical basis required for a federal facility investment of this scope.