How to Select Aperture Size for Micro Perforated Panels？

25 Jun, 2026

TAG: Micro Perforated Panels, acoustic panel,TianGe Acoustic

As a common acoustic material, micro-perforated acoustic panels are widely used in venues such as conference halls, gymnasiums, and multi-purpose halls; their primary function is to reduce ambient noise and enhance the quality of the acoustic environment. Pore size is a critical parameter influencing panel performance, directly determining sound absorption efficiency across various frequencies, airflow permeability, and structural integrity. Consequently, the scientific selection of pore size is a vital step in optimizing acoustic design. The following analysis examines the mechanisms by which pore size affects sound absorption capabilities and outlines strategies for selection.

How to Select Aperture Size for Micro Perforated Panels？-1

Critical Impact of Pore Size on Sound Absorption

Pore Size and Sound Absorption: Frequency Matching Matters

The sound absorption coefficient (α) is a key indicator of a material's sound-absorbing capability, ranging from 0 to 1; a higher value indicates more effective sound absorption. The relationship between pore size and the sound absorption coefficient exhibits a distinct frequency dependence:

Small apertures (≤2 mm): By enhancing the air-spring effect and Helmholtz resonance, these provide outstanding sound absorption for low-to-mid frequencies (125 Hz–1000 Hz). For instance, a perforated panel with 2 mm apertures can achieve a sound absorption coefficient of 0.6 at 125 Hz, though its absorption capacity at high frequencies (>2000 Hz) is relatively weak.

Medium aperture (4 mm–6 mm): Balances absorption across both low-to-mid and mid-to-high frequency ranges (500 Hz–2000 Hz); features a balanced sound absorption curve, making it a versatile choice for most applications. For instance, a perforated panel with a 5 mm aperture achieves a sound absorption coefficient of 0.75 at 1000 Hz.

Large apertures (≥10 mm): Resonance effects are diminished, allowing sound waves to penetrate the openings more easily; this results in significant sound absorption at high frequencies (1000 Hz–4000 Hz), though low-frequency absorption capacity is insufficient. For instance, a perforated panel with a 10 mm aperture can achieve a sound absorption coefficient of 0.85 at 4000 Hz.

How to Select Aperture Size for Micro Perforated Panels？-1

Typical application scenarios:

Small aperture: Concert halls, cinemas, mechanical equipment rooms (predominantly low-frequency noise)

Medium-sized aperture: conference rooms, classrooms, libraries (requiring high speech intelligibility)

Large aperture: Open-plan offices, shopping malls, exhibition halls (requiring high-frequency noise control)

Pore Size and Permeability: Acoustics vs Strength

Air permeability refers to the capacity for air to flow through the pores of an acoustic panel and is positively correlated with pore size. Larger pores result in higher air permeability, facilitating sufficient friction and energy dissipation between sound waves and the material, thereby enhancing sound absorption efficiency. However, excessively large pores compromise the structural strength of the panel and increase the risk of deformation. For instance, when subjected to external force, an acoustic panel with 10 mm pores exhibits a flexural strength approximately 30% lower than that of a panel with 5 mm pores.

Design recommendation: Prioritize larger aperture sizes to enhance airflow, provided structural integrity is maintained; if enhanced low-frequency absorption is required, a combination of small apertures and a high perforation ratio (e.g., 2 mm aperture, 20% perforation ratio) may be employed to balance sound absorption performance with mechanical strength.

Trade-off Between Pore Size and Surface Impedance

Surface impedance is a parameter representing the resistance encountered by sound waves during reflection and transmission at a material's surface. Smaller pore sizes result in higher surface impedance, which enhances sound wave reflection and yields significant high-frequency absorption; conversely, larger pore sizes result in lower surface impedance, allowing sound waves to penetrate more easily and improving low-frequency absorption. For instance, a sound-absorbing panel with a 2 mm pore size exhibits twice the surface impedance of a panel with a 10 mm pore size regarding 2000 Hz sound waves, leading to a 40% increase in high-frequency absorption efficiency.

Application logic: High-frequency noise (such as human voices or electronic equipment noise) requires small apertures to suppress reflection, whereas low-frequency noise (such as traffic noise or mechanical vibration) requires large apertures to lower impedance and facilitate transmission and absorption.

How to Select Aperture Size for Micro Perforated Panels？-1

Optimizing Perforation Diameters in Micro Perforated Panels

Precisely Analyze Acoustic Requirements of Applications

Select the aperture size based on the noise frequency distribution characteristics of the location:

For scenarios dominated by high frequencies (e.g., recording studios, theaters): Prioritize sound-absorbing panels with apertures of ≤2 mm to enhance the absorption of sound waves above 2000 Hz.

Low-frequency dominant environments (e.g., factory workshops, subway tunnels): Select panels with an aperture of ≥8 mm, focusing on the absorption of sound waves in the 125 Hz–500 Hz range.

For full-frequency application scenarios (e.g., multi-purpose halls, sports arenas): Utilize medium-sized apertures (4 mm–6 mm) or a layered design (larger apertures in the upper layer to control high frequencies, and smaller apertures in the lower layer to absorb low frequencies).

Trade-off: Structural Strength vs Ventilation

Balancing performance through open-area ratio optimization:

Low perforation rate (<10%): Weak sound-absorbing effect; suitable for decorative purposes or minor acoustic optimization.

Moderate open area ratio (10%–20%): Balances sound absorption with structural strength; suitable for most standard applications.

High perforation rate (>20%): Enhances sound absorption capabilities, though it necessitates increasing the panel thickness or using a metal framework for reinforcement to maintain structural strength.

Case study: A conference room utilized sound-absorbing panels with a 5 mm aperture and a 15% perforation rate; this configuration ensured structural safety while achieving a sound absorption coefficient of ≥0.7 within the 500 Hz–2000 Hz frequency range.

How to Select Aperture Size for Micro Perforated Panels？-1