Home Theater Glossary: 22 Terms Explained
The words that show up in home theater specs, reviews and how-to guides, explained without jargon. Open any term for the full explanation and what to look for when buying.
- 4K (UHD)
- A resolution of 3840 by 2160 pixels, four times 1080p, that lets you sit closer to a large screen without seeing pixels.
- Read more about 4k (uhd)Related: Best 4K Projectors
- 5.1 / 7.1.4
- Speaker layout shorthand: the first number is main speakers, the second is subwoofers, the third is overhead or height speakers.
- Read more about 5.1 / 7.1.4
- ALR screen
- An ambient light rejecting screen built to reflect projector light toward viewers while rejecting light from other angles in the room.
- Read more about alr screenRelated: Best ALR Projector Screens
- AV receiver
- The central hub that decodes surround sound formats, powers speakers directly and switches between HDMI video sources.
- Read more about av receiverRelated: Best AV Receivers
- Bias lighting
- A soft light placed behind the TV or screen that reduces eye strain and makes on-screen blacks look deeper in a dark room.
- Read more about bias lightingRelated: Best Bias Lighting
- Center channel
- The speaker placed under or above the screen that carries most movie and show dialogue in a surround sound system.
- Read more about center channelRelated: Best Center Channel Speakers
- Contrast ratio
- The difference between the brightest white and the darkest black a display can show at the same time, key to picture depth.
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- Dolby Atmos
- An object-based surround format that adds height channels so sound can move above and around the listener, not just side to side.
- Read more about dolby atmosRelated: Best Dolby Atmos Speakers
- eARC
- Enhanced Audio Return Channel, an HDMI feature that sends lossless, high-bitrate audio from a TV back to a soundbar or receiver.
- Read more about earc
- First reflection points
- Spots on the side walls where sound from the front speakers bounces to your ears first, a common place for acoustic panels.
- Read more about first reflection pointsRelated: Best Acoustic Panels
- HDMI 2.1
- An HDMI version with enough bandwidth for 4K at high frame rates, needed for smooth 4K120 gaming and some Atmos audio formats.
- Read more about hdmi 2.1
- HDR
- High dynamic range video with brighter highlights and deeper shadows, delivered through formats like HDR10, HDR10+ and Dolby Vision.
- Read more about hdr
- Keystone correction
- A projector setting that digitally squares up a trapezoidal image caused by mounting the projector off center or at an angle.
- Read more about keystone correction
- Lip sync delay
- A mismatch between audio and video timing, often just a few frames, that makes dialogue seem slightly out of sync with lips.
- Read more about lip sync delay
- Lumens
- A measure of projector brightness. Rooms with ambient light need considerably more lumens than a fully dark dedicated theater room.
- Read more about lumens
- Refresh rate
- How many times per second a display redraws the image, measured in Hz, which affects motion smoothness and gaming responsiveness.
- Read more about refresh rate
- Room correction
- Automatic calibration built into an AV receiver that measures the room with a microphone and adjusts speaker levels and timing.
- Read more about room correction
- Screen gain
- A rating of how much light a projector screen reflects back compared to a flat white reference surface of the same size.
- Read more about screen gain
- Speaker sensitivity
- How loud a speaker plays for a given amount of amplifier power, measured in decibels, which affects how hard an amp must work.
- Read more about speaker sensitivity
- Subwoofer crossover
- The frequency below which bass is routed to the subwoofer instead of the main speakers, commonly set around 80 Hz.
- Read more about subwoofer crossover
- Throw ratio
- Projector distance divided by image width, used to figure out how far back a projector needs to sit for a given screen size.
- Read more about throw ratioRelated: Best Projectors
- Viewing angle
- How much of your field of view the screen fills from your main seat, which drives how immersive the picture feels.
- Read more about viewing angle