Home Theater Jargon Decoded: A Plain-English Glossary

Dolby Atmos

A surround-sound format that adds height channels to traditional side-and-rear audio, creating a three-dimensional sound field. It's supported by many streaming services, Blu-ray discs, soundbars, and AV receivers. The number of speakers you have determines how much of the effect you actually hear.

DTS:X

A competing 3D audio format to Dolby Atmos, developed by DTS. It similarly adds overhead sound positioning and is object-based, meaning audio engineers can place sounds anywhere in the space around the listener. Support varies by hardware and content source.

HDMI eARC

Enhanced Audio Return Channel — a feature on newer HDMI ports that lets your TV send high-quality audio back to a soundbar or receiver without a separate cable. It supports lossless formats like Dolby TrueHD and DTS-HD Master Audio, which standard ARC cannot handle.

HDR (High Dynamic Range)

A display technology that expands the range between the darkest blacks and brightest whites a screen can show. Common formats include HDR10, HDR10+, and Dolby Vision. Each requires both compatible content and a compatible display to make a visible difference.

Refresh Rate

How many times per second a TV redraws the image on screen, measured in hertz (Hz). A 60 Hz panel refreshes 60 times per second; a 120 Hz panel refreshes 120 times. Higher refresh rates can reduce motion blur in fast-moving content like sports or action films.

5.1 / 7.1 / 5.1.2 (Channel Configuration)

A shorthand for the number of speakers in a surround-sound setup. The first number is full-range speakers, the second is subwoofers, and the third (when present) is overhead or upward-firing speakers for formats like Atmos. A 5.1.2 system, for example, has five speakers, one subwoofer, and two height channels.

AV Receiver

The central hub of a traditional home theater system. It accepts audio and video inputs from multiple sources — streaming players, game consoles, Blu-ray players — amplifies audio, and routes signals to your speakers and TV. Often abbreviated as AVR.

Subwoofer

A dedicated speaker designed to reproduce very low-frequency sounds, typically below 80–120 Hz. Subwoofers handle the bass — the rumble of explosions, the thump of music — that smaller speakers cannot produce effectively. They're the ".1" in any channel configuration number.

4K (Ultra HD)

A display resolution of approximately 3,840 × 2,160 pixels — four times the pixel count of 1080p HD. More pixels generally means finer detail, but the visible benefit depends on screen size and how far you sit from the TV.

Local Dimming

A backlight feature on LCD TVs that dims specific zones of the screen independently to improve contrast — making dark areas darker without affecting bright areas. The quality varies significantly based on how many dimming zones the TV uses.

Latency (Input Lag)

The delay between a signal being sent — say, pressing a button on a game controller — and the result appearing on screen. Measured in milliseconds. TVs with a dedicated Game Mode typically reduce input lag to improve responsiveness.

Bitrate

The amount of data processed per second in a video or audio stream, usually measured in megabits per second (Mbps). Higher bitrates generally preserve more detail and reduce compression artifacts, but they also require more bandwidth or storage space.