Branca testing equipments for acoustic materials

Branca Idealair manufactures testing equipment specifically designed for measuring the acoustic impedance and Non-Linear Factor (NLF) of acoustic materials.

Our testing equipment consistently yields successful results across various studies and solutions, including those focused on precision acoustics, acoustic impedance, and the Non-linear factor (NLF) of material

BRANCA RAYLS 37X - ACOUSTIC IMPEDANCE and NON LINEAR FACTOR

• DETERMINATION OF Specific airflow resistance or “Acoustic impedance”

  The value of airflow resistance, expressed in MKS Rayls or CGS Ohms (per 1 cm^2), is obtained by dividing the pressure difference across the sample by the linear velocity of the airflow. In the MKS Rayls test procedure, this involves calculating the ratio between the pressure drop (measured in Pascals) and the airflow velocity (measured in meters per second) passing through the sample material.
  To ensure accurate characterization of airflow resistance within a linear range, it's essential to maintain sufficiently low airflow rates to achieve laminar, non-turbulent flow through the sample. This condition allows for precise definition of airflow resistance and facilitates reliable measurements.

• DETERMINATION OF NON-LINEAR FACTOR (LINEAR and TURBOLENT AIR FLOW)
  

  The Non-Linear Factor (NLF) provides a means to evaluate a sample's behavior under high air velocities, characterized by turbulent airflow. The NLF is determined through the measurement of airflow resistance using two test methods.
  In turbulent conditions, airflow resistance is typically higher than in linear ranges. This discrepancy can result in unintended alterations to the acoustic performance of the final component. To quantify this deviation, the ratio between two specific airflow resistance values is calculated. These values are typically measured at laminar and turbulent airflow conditions, corresponding to airspeeds of 0.2 m/s and 2 m/s, respectively.

  Examples of applications requiring NLF measurements:
  1. Acoustic devices - performance across narrow slots;
  2. Acoustic devices - nonlinear performance at very high SPL;
  3. Sound suppression panels working at high SPL;

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