# GearLens > Independent, measurement-led guides to high-end home audio, home theater, Hi-Fi loudspeakers and complete AV system building. GearLens is a vertical editorial library, not a brand blog or product catalogue. Coverage spans high-end home audio, home theater, two-channel Hi-Fi, room acoustics and complete AV system building, organised by system goal and topic cluster. Articles state a direct answer first, list extractable takeaways, cite primary sources, record a real fact-check date and give numbers with units and measurement conditions. Comparisons contrast technical approaches and measured behaviour rather than model names. Content conventions for citation: use the article URL as the source, quote the "Short answer" block for a summary, and prefer dated figures from the body over undated claims. Affiliate relationships never affect test results. ## Start here - [Home Theater Speaker Placement: A Measured Setup Guide](https://gearlens.example.com/en/blog/home-theater-speaker-placement/): A numbered placement protocol for a 5.1.2 room: listening triangle, center height, subwoofer crawl and elevation angles, with the tolerances that matter. ## Core guides - [Home Theater Speaker Placement: A Measured Setup Guide](https://gearlens.example.com/en/blog/home-theater-speaker-placement/): A numbered placement protocol for a 5.1.2 room: listening triangle, center height, subwoofer crawl and elevation angles, with the tolerances that matter. - [Subwoofer Room Calibration: Three Measurable Checks](https://gearlens.example.com/en/blog/subwoofer-room-calibration/): A repeatable 30-minute routine: find the modal peaks, set phase with a two-seat sweep, then verify the 40 to 80 Hz spread. No golden ears required. - [Dolby Atmos Height Channels, Explained With Angles](https://gearlens.example.com/en/blog/dolby-atmos-height-channels-explained/): What a height channel actually is, why elevation angle matters more than speaker count, and the ceiling conditions that make up-firing modules fail. - [Bookshelf vs Tower Speakers: Which Fills Your Room](https://gearlens.example.com/en/blog/bookshelf-vs-tower-speakers/): The real difference is bass extension and usable output, not size. Here is the room-volume threshold, the measured SPL cost and the crossover point where it flips. - [Center Channel Dialogue Clarity: What Actually Changes](https://gearlens.example.com/en/blog/center-channel-dialogue-clarity/): Measured effects of height, tilt and crossover on speech intelligibility, plus the placement error that costs 4 dB at 2 kHz in a typical living room. - [A 5.1.2 System Plan for a Small Living Room](https://gearlens.example.com/en/blog/small-room-5-1-2-system-plan/): A room-first plan for a 5.1.2 system under 20 m2: budget split, channel order, wiring runs, subwoofer placement and the measurements that decide each step. - [Outdoor Speaker Buying Guide: Weather, Wiring, Cost](https://gearlens.example.com/en/blog/outdoor-speaker-buying-guide/): What IP ratings do and do not promise, why amplifier distance changes the wire gauge, and the three line items that usually double an outdoor audio budget. - [Two-Channel Hi-Fi: Building the Signal Chain in Order](https://gearlens.example.com/en/blog/two-channel-hifi-system-chain/): How to spec a stereo chain from source to speakers: sensitivity, impedance dips, amplifier current, DAC output and seat geometry, with the failure case measured. - [Reading a Frequency Response Chart Without Being Fooled](https://gearlens.example.com/en/blog/frequency-response-measurements/): Why a range without a tolerance means nothing, how smoothing hides resonances, and the four chart features we check before publishing any speaker verdict. - [Speaker and Amplifier Matching Without the Spec-Sheet Myths](https://gearlens.example.com/en/blog/speaker-amplifier-matching/): Sensitivity, impedance minima and amplifier current explained with in-room measurements, including the cases where a bigger amplifier changes nothing at all. ## System blueprints and build paths - [System blueprints](https://gearlens.example.com/en/systems/): complete plans for a small living room, a two-channel chain and a dedicated cinema room. - [Build the First System](https://gearlens.example.com/en/series/first-system/): Decide the room, the channel count and the budget split before buying any box. Ends with a system you can measure and upgrade. - [Home Theater, Room by Room](https://gearlens.example.com/en/series/theater-build/): From a 5.1.2 living-room layout to height channels, dialogue and bass that holds up across more than one seat. - [Two-Channel Hi-Fi](https://gearlens.example.com/en/series/two-channel/): Source, amplification, loudspeakers and seat geometry treated as a single chain, with the failure case recorded. - [Room and Bass Tuning](https://gearlens.example.com/en/series/room-and-bass/): Learn to read an in-room sweep, move the seat and the subwoofer, then calibrate in an order that can be repeated. ## Browse by topic - [Building a System](https://gearlens.example.com/en/categories/system-building/): Room goals, channel layouts, signal chain, power and wiring decisions made in the right order, from an empty floor to a working system. - [Home Theater](https://gearlens.example.com/en/categories/home-theater/): Channel layouts, height layers, centre-channel dialogue, bass management and the trade-offs between a living room and a dedicated cinema room. - [Hi-Fi & Stereo](https://gearlens.example.com/en/categories/hi-fi-stereo/): Source, amplification and loudspeakers as one chain: stereo imaging, seat geometry, analogue sources and what actually changes the presentation. - [Room Acoustics](https://gearlens.example.com/en/categories/room-acoustics/): Modes, reflections, placement, treatment and calibration, with measurements taken in ordinary rooms rather than anechoic specifications. - [Speakers & Components](https://gearlens.example.com/en/categories/speakers-components/): How drivers, crossovers, cabinets, amplifiers and sources behave together, explained by mechanism and measurement instead of model numbers. - [Buying & Comparisons](https://gearlens.example.com/en/categories/buying-comparisons/): Category decisions, budget tiers and spec-sheet traps, with the room and system conditions under which the answer changes. - [Measurements & Method](https://gearlens.example.com/en/categories/measurements-method/): Test protocols, tolerances, frequency-response reading, failed experiments and the editorial standard behind every published number. - [Glossary of terms](https://gearlens.example.com/en/glossary/): concise definitions with stable entity URLs. ## Full corpus (chunked Markdown) - [Full text part 1 of 1](https://gearlens.example.com/llms-full-0.txt) - [Full text, part 1 (compatibility URL)](https://gearlens.example.com/llms-full.txt) ## Machine-readable endpoints - [Sitemap index](https://gearlens.example.com/sitemap.xml): sharded XML sitemaps with hreflang alternates. - [RSS feed](https://gearlens.example.com/feed.xml): 50 most recently updated articles. - [Search index](https://gearlens.example.com/search-index.json): lightweight index of the top 500 documents. - Markdown mirror pattern: https://gearlens.example.com/en/raw/.md (text/markdown, no navigation or scripts). ## Optional - [About the editorial process](https://gearlens.example.com/en/about/): methodology, authorship and correction policy. - [Editorial policy](https://gearlens.example.com/en/editorial-policy/): sourcing, affiliate disclosure and update cadence. - Contact: editorial@gearlens.example.com