An acoustic camera is one of the most powerful tools available to engineers who need to locate, visualize, and quantify noise sources in complex environments. Whether you are troubleshooting an unwanted rattle inside a vehicle cabin, tracking down air leaks in a compressed-air system, or verifying the acoustic performance of a home appliance on the production line, an acoustic camera can do in minutes what traditional measurement methods take hours—or fail to do at all. This complete guide explains how acoustic cameras work, where they are used, what to look for when choosing one, and how they compare to conventional sound level meters. By the end, you will have a clear understanding of sound source localization technology and the confidence to select the right acoustic imaging camera for your application. What Is an Acoustic Camera? An acoustic camera is an instrument that combines a microphone array with a digital camera to produce a real-time visual map of sound—often called an acoustic image or sound map. The colored overlay shows exactly where noise is coming from, its relative intensity, and how it changes over time or frequency. Unlike a single microphone, which can measure sound pressure at one point but cannot tell you where the sound originates, an acoustic camera performs noise source identification across a wide field of view simultaneously. Core Components Component Role Microphone array Captures sound at multiple spatial positions Digital camera Provides the optical reference image Data acquisition hardware Digitizes and synchronizes all microphone channels Beamforming software Computes the sound map from array data How Does an Acoustic Camera Work? The Beamforming Principle The physics behind an acoustic camera relies on a technique called beamforming. Here is a simplified explanation: Sound waves arrive at the microphone array. Because microphones are at different positions, the same wavefront reaches each microphone at a slightly different time. Time delays are calculated. For every candidate point in the measurement space, the software calculates the expected arrival-time differences across all microphones. Signals are shifted and summed. The software shifts each microphone signal by the predicted delay and sums them. If the candidate point is the true source, the signals add constructively, producing a strong peak. If not, they partially cancel. A sound map is generated. By scanning thousands of candidate points, the algorithm builds a 2D (or 3D) color map of acoustic intensity overlaid on the camera image. This process is called delay-and-sum beamforming and is the foundation of most acoustic cameras. More advanced algorithms—such as CLEAN-SC, functional beamforming, and deconvolution approaches—further sharpen the image and improve dynamic range. Frequency Range and Array Design The usable frequency range of an acoustic camera depends on the array geometry: Low-frequency limit is governed by the overall array diameter. A larger array resolves lower frequencies. High-frequency limit is governed by the spacing between adjacent microphones. Closer spacing avoids spatial aliasing at higher frequencies. Typical acoustic cameras cover 200 Hz to 12 kHz or wider, with some specialized arrays reaching above 20 kHz for applications like leak detection. Applications of Acoustic Cameras Automotive NVH (Noise, Vibration, and Harshness) Acoustic cameras are indispensable in automotive development. Engineers use them to: Identify wind noise sources around door seals, mirrors, and A-pillars in wind-tunnel tests. Locate interior noise paths—dashboard rattles, HVAC duct noise, powertrain radiation—during road tests. Validate pass-by noise levels under ISO 362 by mapping exterior noise sources in real time. Home Appliance Noise Reduction Consumer expectations for quiet appliances are rising. Manufacturers of washing machines, refrigerators, dishwashers, and air conditioners use acoustic cameras to: Compare noise signatures before and after design changes. Detect abnormal noise patterns in end-of-line (EOL) quality checks. Pinpoint noise from specific subcomponents (compressors, fans, pumps) within a fully assembled product. Industrial Equipment and Predictive Maintenance In factories, acoustic cameras quickly identify: Compressed-air leaks, which account for 20–30% of energy waste in many plants. Bearing defects in motors, turbines, and conveyors—often before they become audible to the human ear. Electrical discharge (partial discharge) in high-voltage switchgear and transformers. Building Acoustics and Environmental Noise Acoustic cameras help building consultants identify sound transmission paths through walls, windows, and HVAC penetrations, verify the effectiveness of sound barriers, and map noise from construction sites. Power Generation and Renewable Energy Wind turbine manufacturers and operators use acoustic cameras to measure blade noise, detect trailing-edge damage, and comply with environmental noise limits. How to Choose an Acoustic Camera 1. Array Configuration and Size Planar arrays (flat) are the most common—lightweight, portable, and suitable for front-facing measurements. Spherical or 3D arrays capture sound from all directions for interior cabin or room acoustic studies. Number of microphones: More microphones improve spatial resolution and dynamic range. Entry-level: 30–64; high-performance: 100–200+. 2. Frequency Range Application Typical Frequency Range Automotive NVH (interior) 200 Hz – 8 kHz Appliance noise 300 Hz – 12 kHz Air leak detection 2 kHz – 20 kHz+ Building acoustics 100 Hz – 5 kHz 3. Software Capabilities Real-time beamforming, advanced algorithms (CLEAN-SC, deconvolution), time-domain and frequency-domain analysis, video recording with synchronized audio, and flexible export formats. 4. Portability and Ease of Use For field measurements, a lightweight, battery-powered, single-person-operable system is essential. A Closer Look: CRYSOUND Acoustic Imaging Systems The CRY8124 is a large-format planar array with 200 MEMS microphones, optimized for high-resolution measurements in automotive NVH and industrial applications. The CRY2623 is a compact, handheld acoustic camera with 128 microphones designed for rapid field inspections—air leak detection, electrical inspection, and predictive maintenance. Both systems include real-time beamforming software with CLEAN-SC deconvolution, video overlay, and spectral analysis. Acoustic Camera vs. Sound Level Meter: When to Use Which Criterion Sound Level Meter Acoustic Camera What it measures Sound pressure level at one point Sound source location and relative level across a surface Source identification No Yes—visual map shows source locations Regulatory compliance Yes—traceable dB(A)/dB(C) values per IEC 61672 Limited Cost $500–$5,000 $15,000–$150,000+ Best for SPL measurement, noise monitoring, compliance Root-cause analysis, noise reduction, leak detection In practice, the two tools are complementary. A sound level meter confirms how loud a problem is; an acoustic camera shows where it is. Conclusion Acoustic cameras have transformed the way engineers approach noise problems. By making sound visible, they accelerate root-cause analysis, reduce development cycles, and enable quality controls that were previously impractical. Ready to see your noise sources? Contact CRYSOUND for a personalized consultation or request a live demo with your application.

Every speaker, microphone, headphone, and hearing aid that leaves a production line must meet precise acoustic specifications. This guide walks you through the transition from manual electroacoustic testing to a fully automated audio test system. Why Automate? Manual Testing vs. Automated Testing The Manual Approach A typical manual setup consists of a signal generator, power amplifier, measurement microphone, audio analyzer, and an operator who connects the DUT, triggers each measurement, reads results, and records pass/fail. Limitations: Slow (2–5 min/unit), operator-dependent, error-prone, difficult to scale. The Automated Approach Factor Manual Automated Test time per unit 2–5 minutes 5–15 seconds Throughput 15–25 units/hour 200–500+ units/hour Repeatability Operator-dependent < 0.5 dB variation Data logging Manual/partial Automatic, 100% traceability Defect detection Subjective Algorithmic, consistent ROI is typically realized within 6–12 months for mid-volume production (>500 units/day). System Architecture: Hardware and Software 1. Signal Generation and Acquisition (Audio Analyzer) Modern audio analyzers integrate signal generation and acquisition in a single instrument with USB or Ethernet connectivity. 2. Acoustic Test Chamber (Test Fixture) The DUT must be tested in a controlled acoustic environment—anechoic coupler, semi-anechoic test chamber, or IEC 60318-compliant ear simulator. 3. Switching and Connectivity Relay matrix, barcode/QR scanner, PLC or I/O controller for conveyor systems and MES integration. 4. Test Software CRYSOUND's OpenTest platform provides a drag-and-drop test sequence editor, multi-station deployment, and built-in SPC dashboards. Key Electroacoustic Test Parameters Frequency Response: SPL vs. frequency curve evaluated against upper and lower limit masks Total Harmonic Distortion (THD): < 1% at 1 kHz rated power typical spec Rub and Buzz (R&B): Detects mechanical defects—loose particles, voice coil rub, rattling Impedance: Reveals resonant frequency, DC resistance, electrical behavior Polarity: Verifies correct phase direction Sensitivity: SPL at reference distance for given input Seal and Leak Test: For enclosed products Step-by-Step: Building Your Automated Test Line Define Test Requirements — List every parameter, pass/fail limits, cycle time, and applicable standards. Design the Test Station Layout — Calculate station count, inline vs. offline, one-sided vs. multi-sided. Select and Procure Equipment — Audio analyzer, microphones, test chamber, switching hardware, software. Build and Integrate — Assemble fixtures, wire signal paths, install software, connect PLC/MES. Establish Golden Unit Calibration — Select 5–10 reference units, define reference curves and repeatability baseline. Validate and Fine-Tune Limits — Run pilot batch of 100–500 units, analyze yield, adjust thresholds. Train Operators and Launch — Document procedures, go live with full data logging. Continuous Improvement — Daily calibration verification, SPC monitoring, periodic microphone recalibration. Common Pitfalls and How to Avoid Them Inadequate Acoustic Isolation: Design chamber for ≥30 dB insertion loss. Over-Tight Limits at Launch: Use pilot-batch statistics (mean ± 3σ). Ignoring Fixture Repeatability: Use positive-location fixtures, verify with gauge R&R. No Reference Unit Tracking: Measure reference unit at start of each shift. Conclusion Transitioning from manual to automated electroacoustic testing pays for itself through higher throughput, better repeatability, and comprehensive data traceability. The acoustic quality your customers hear is only as good as the test system that verified it. Ready to automate your electroacoustic test line? Contact CRYSOUND to discuss your production testing requirements. From audio analyzers and measurement microphones to the OpenTest software platform, CRYSOUND provides end-to-end solutions for production line audio testing.

Sound pressure level, sound intensity, and sound power are three fundamental quantities in acoustic measurement, yet they are routinely confused—even by experienced engineers. This guide explains what each quantity physically represents, how they relate to each other, how to measure them according to international standards, and—most importantly—when to use which one in real engineering practice. The Three Quantities at a Glance Quantity Symbol Unit What It Describes Depends on Environment? Sound Pressure p (level: Lp) Pa (dB re 20 µPa) Force per unit area at a point Yes Sound Intensity I (level: LI) W/m² (dB re 1 pW/m²) Energy flow per unit area in a direction Partially Sound Power W (level: LW) W (dB re 1 pW) Total acoustic energy radiated by a source No The key distinction: sound pressure and intensity depend on where you measure; sound power is an intrinsic property of the source. Sound Pressure: What You Hear Sound pressure is the local fluctuation in air pressure caused by a sound wave. Sound pressure level (SPL) is expressed as: Lp = 20 × log₁₀(p / p₀) where p₀ = 20 µPa is the reference pressure. Key characteristics: Scalar quantity, location-dependent, easy to measure with a single calibrated microphone. When to use: Noise exposure assessment (ISO 9612), environmental noise monitoring, product noise labeling, quick field checks. Sound Intensity: Energy Flow with Direction Sound intensity is the rate of acoustic energy flow through a unit area in a specified direction—a vector quantity with both magnitude and direction. Key characteristics: Directional, less sensitive to background noise, requires specialized two-microphone probe. When to use: Sound power determination in situ (ISO 9614), noise path identification, transmission loss testing. Sound Power: The Source’s Intrinsic Noise Rating Sound power is the total acoustic energy radiated by a source per unit time—independent of environment. When to use: Product noise specifications (EU Machinery Directive), noise prediction and modeling, procurement and tendering. Measurement Methods and ISO Standards Sound Power via Sound Pressure (ISO 3741–3747) Standard Environment Accuracy ISO 3741 Reverberation room Precision (Grade 1) ISO 3744 Free field over reflecting plane Engineering (Grade 2) ISO 3745 Anechoic / hemi-anechoic room Precision (Grade 1) ISO 3746 In situ (any environment) Survey (Grade 3) Sound Power via Sound Intensity (ISO 9614 series) The advantage of the intensity method is its tolerance of background noise and reflections. Measurement Equipment CRYSOUND’s multi-channel data acquisition range includes prepolarized and externally polarized models in 1/2-inch and 1/4-inch formats, covering frequency ranges from 3 Hz to over 100 kHz. CRYSOUND’s data acquisition platforms support intensity measurement with real-time cross-spectral analysis across all channels. Practical Decision Guide: Which Quantity Do You Need? “I need to check workplace noise regulations.” → Measure sound pressure level per ISO 9612. “I need to compare noise output of two machines.” → Request or measure sound power level. “I need to find where noise leaks through a wall.” → Measure sound intensity on the receiving side. “I need to predict how loud a new machine will be.” → Get the machine’s sound power level, then model. “I need to meet the EU Machinery Directive.” → Determine sound power level per ISO 3744/3746. Summary Table Sound Pressure Level Sound Intensity Level Sound Power Level Quantity type Scalar Vector Scalar Depends on distance Yes Yes No Depends on room Yes Partially No Primary instrument Sound level meter Intensity probe Calculated from SPL or intensity Key standards IEC 61672 ISO 9614 ISO 3741–3747 Best for Exposure, compliance Path analysis, in-situ power Source comparison, prediction Conclusion Sound pressure tells you how loud it is here. Sound intensity tells you how much energy is flowing that way. Sound power tells you how much noise the source makes, period. By understanding these distinctions and selecting the right measurement method, you avoid costly errors and arrive at actionable acoustic data faster. Need help selecting the right acoustic measurement equipment? Contact CRYSOUND to discuss your application with our acoustics team.