Resource
Squiglink
Interactive frequency-response graph tool for in-ear monitors and headphones, hosting databases measured on IEC 711-style rigs, with target curves, smoothing and normalisation options and explanations of each frequency region.
Verification sources
Related resources
In-Ear Fidelity
measurement
Crinacle's IEM and headphone measurement site, with a graph database of in-ear monitors measured on a B&K Type 5128, the IEF target curve and long-form posts and product notes.
Sources
RTINGS.com
measurement
Independent product-testing lab that buys its own units and tests them on the same bench across 28 categories, including headphones, soundbars and TVs, from a 40,000 sq ft facility. It is supported by memberships and affiliate links.
Sources
Audio Precision
tool
Audio Precision supplies APx audio analyzers and measurement software for engineering and production testing. Its electroacoustic options cover driver characterization, loudspeaker response, impedance and manufacturing faults, making it an equipment-testing resource rather than a consumer listening-room calibration app.
Sources
AutoEq
tool
Free web tool that generates headphone equalisation settings: pick your headphones and equaliser app, or import a CSV of measurements, and it produces optimal EQ parameters, with a live demo for comparison.
Sources
eCoustics
publication
eCoustics is an online publication covering hi-fi, home theater, headphones, music and consumer technology. Founded as a reviews portal, it now combines original reviews, product news, how-to articles and review aggregation, with named authors and separate editorial and announcement sections.
Sources
Headfonics
publication
Personal-audio publication established in 2011, focused on subjective reviews of headphones, IEMs, amplifiers and digital sources. Its stated method combines listening, real-world use and competing-product comparisons, with coverage ranging from entry-level equipment to high-end portable and desktop systems.