Blogs
A2DP (Advanced Audio Distribution Profile) is the core Classic Bluetooth profile for high-quality audio streaming. This article provides an overview of how A2DP transmits music, explains its position in the Bluetooth protocol stack, and introduces a practical A2DP testing workflow using the CRY578 Bluetooth LE Audio Interface. How Does A2DP Transmit Music? A2DP is the […]
Sound is everywhere in our daily life: birdsong, street noise, engine roar, even the faint airflow from an air conditioner. For people, sound is not only about whether we can hear it, but whether it feels comfortable, is disturbing, or poses a risk. The same 70 dB can feel completely different; and when something feels […]
Valves are the "core control components" of pipeline systems. They perform four key functions-opening/closing, regulating, isolating, and directing-enabling precise control of fluid flow. Once sealing integrity fails, minor cases can lead to process upsets and energy losses, while severe cases may result in fires or explosions, toxic exposure, or environmental pollution. We built a valve […]
Sound Level Meter
This article presents a multi-channel sound level meter developed on the OpenTest platform and designed to meet the technical requirements of IEC 61672-1. By integrating the SonoDAQ data acquisition system with measurement-grade microphones, the system implements standard A/C/Z frequency weightings, F/S/I time weightings, and enables accurate measurement of standard acoustic quantities such as Lp, Leq, […]
In acoustic testing, acoustic metrology, and product noise evaluation, the term measurement microphone typically refers to a condenser measurement microphone. Its signal generation relies on a polarization electric field: sound pressure changes the capacitance, and the front-end circuitry converts this change into an electrical signal. Depending on how the polarization field is provided, measurement microphones generally […]
This integrated single-station EoL test solution enables automotive HVAC air vent suppliers to perform NVH (noise/anomalous sound), motor electrical testing, and vane presence detection in a single inspection step, helping to improve overall test efficiency and reduce labor dependency. Modern automotive HVAC air vent assemblies increasingly integrate multiple drive motors, multi-row vanes (louvers), and smart […]
In industrial production and environmental monitoring, excessive noise implies compliance risks or potential complaint disputes. To handle this, you need a professional sound level meter (SLM) that provides "credible, traceable, and analyzable data." Faced with price differences ranging from hundreds to tens of thousands of dollars, and a complex array of parameters, how do you […]
Sound Quality
Learn how to measure Loudness (ISO 532-1), Sharpness, and Tonality (ECMA-74) with OpenTest - free, open-source software. Step-by-step guide for automotive NVH, consumer electronics & home appliances engineers. This article is for engineers working in acoustics and vibration testing. It introduces how to perform sound quality measurements in OpenTest based on the ISO 532 loudness […]
Measurement microphones are used in acoustic metrology, type-approval testing, and engineering measurements. Unlike general audio capture applications, measurement scenarios place far greater emphasis on consistency and traceability: the same microphone should deliver stable output when re-tested over time; variation within a production lot should be sufficiently small; and performance fluctuations between lots should remain controllable. […]
Before you begin any formal data acquisition work, one critical step is connecting the DAQ front end to the PC. In day‑to‑day engineering, the most common options include USB direct connection, Wi‑Fi wireless, Ethernet, and PXIe. This article introduces these four common connection methods from several angles-how they differ, where each one shines, and their […]
CRY580 A²B Interface is a bidirectional bridge designed to connect the A²B (Automotive Audio Bus) ecosystem with standard test & measurement setups (e.g., SonoDAQ, CRY6151B, Audio Precision). This article explains what makes A²B testing challenging-most analyzers don't have a native A²B interface-and how CRY580 solves it by encoding/decoding A²B streams and converting them into measurable […]
In audio and vibration testing, FFT analysis (Fast Fourier Transform) is one of the tools almost every engineer uses sooner or later: A lot of practical questions are actually asking the same few things: FFT is the most universal entry point to answer these questions. This article will help you clarify three things from an […]
