Are you thinking of buying a home theater projector but feeling overwhelmed by the technical jargon?
With so many options on the market, it can be challenging to understand what all the different terms mean and which features you really need.
That’s why I’ve put together this home theater projector glossary of common terms to help you make an informed decision. From aspect ratio to zoom, you’ll learn everything you need to know in clear and simple language.
The introduction to home theater projectors gives plenty of detail on the features to look for once you’re comfortable with the terminology.
So, whether you’re a first-time buyer or a seasoned pro, read on to discover the essential features of a home theater projector.
Check out the entire home theater glossary for a complete list of technical terms about other aspects of home theater.
- 1080p is a display resolution of 1920 x 1080 pixels (2,073,600 pixels in total). The 'p' stands for progressive scan, meaning the image displays sequentially line-by-line rather than interlaced alternate odd and even lines. It is considered the standard resolution for HDTVs and Blu-ray to provide detailed full HD 1920 x 1080 images without interlacing or fluid motion artifacts.
- The 4K video resolution is part of the Ultra HD family. Also known as 4K UHD, a 4K image is recorded using progressive scan and has a minimum resolution of 3840 x 2160 (8,294,400 pixels) with a 16:9 aspect ratio. 4K has four times as many pixels as 1080p Full HD.
- Also known as 8K Ultra High Definition (UHD), 8K has a display resolution of 7680 x 4320 (33,177,600 pixels). It offers four times the pixels of 4K UHD and sixteen times that of 1080p Full HD. 8K delivers very detailed and crisp visuals, primarily used in top-tier televisions, monitors, and professional cinematography.
- Acoustic Transparency
- Acoustic transparency projector screens use a special material with tiny holes, allowing sound to pass through without affecting quality or volume. This screen type lets you place speakers behind the screen for a more natural, immersive audio experience. Acoustic transparency works well in home theaters where audio quality matters, but speaker placement space is limited.
- Ambient Light Rejection (ALR)
- ALR projector screens reflect light toward the viewer, making the image brighter in rooms with ambient light. The specialized surface prevents washout from lights or windows. Though more expensive than standard screens, ALR improves picture quality where controlling lighting is difficult, like in living rooms.
- Anamorphic Lens
- An anamorphic lens allows home theater projectors to display widescreen movies in their original format without black bars or distortion. The lens condenses the widescreen image to fit the projector's sensor, then stretches it back to full width on the screen. This technique provides an enhanced viewing experience for ultra-wide cinemascope films. However, anamorphic lenses can add cost and may require professional installation.
- ANSI Lumens
- ANSI lumens measure projector brightness as defined by the American National Standards Institute. Higher lumens indicate a brighter projected image. This specification is essential when selecting a home theater projector, especially for rooms with ambient light or large screens. 1500-2000 lumens is usually sufficient for dark, dedicated home theaters. In rooms with some ambient light, look for 2500-4000 lumens. Bright rooms with lots of light require 4000+ lumens for a visible picture. However, brightness is just one factor to consider, along with contrast, color accuracy, resolution, and other features.
- Aspect Ratio
- The aspect ratio defines the shape of a video image - or a TV or projector screen. The aspect ratio of an image is its width divided by its height. For example, the traditional shape of a television picture is 4:3. This means four units across and three units down. Four divided by three = 1.33. So, the aspect ratio of a 4:3 image is 1.33:1 - or 1.33 times wider than long. Looking at the back of a DVD case will tell you the film's aspect ratio. It may say 4:3, or it may say 1.33:1 - or both! The aspect ratio of modern TVs and high-definition pictures is 16:9 - or 1.78:1.
- Black Level
- Black level refers to the depth and quality of dark or black areas displayed by a projector or screen. In simpler terms, it indicates how 'true' or 'deep' the blacks appear. A projector with good black levels will show a clear distinction between dark and slightly darker colors, enhancing the overall contrast and depth of the image. Ideally, you'd want deeper black levels for a richer, more lifelike viewing experience.
- Chipset (Projector)
- A projector's chipset is a semiconductor chip containing micromirror arrays or liquid crystals that reflect and process light. Popular chipsets are Optoma's DLP chips using mirrors, JVC's D-iLA chips built on LCoS technology, and LCD chips from Epson. When comparing projectors, the specific chipset is one of the most critical factors in determining native resolution, clarity, contrast, and overall video quality, and each type has particular pros and cons.
- Color Gamut
- Color gamut refers to the range of colors a projector or TV can display. It is usually measured using the CIE 1931 color space, a mathematical model describing how humans perceive color. A device with a limited color gamut may not reproduce the full range of colors in a movie or video game, resulting in less vibrant and less realistic images. As part of the 4K UHD specification, BT.2020 introduced a wide color gamut, meaning 4K projectors and screens could display many more colors than older 1080p models.
- Color Temperature
- Color temperature is a standard of how "warm" or "cool" the colors in a projected image appear, measured in degrees Kelvin (K). The color temperature setting of a projector adjusts the balance between blue and yellow tones in the picture. A lower color temperature produces a warmer, yellowish image, while a higher temperature produces a cooler, bluish appearance. The color temperature setting is crucial because it can affect the perceived color accuracy of the picture. Many projectors adjust the color temperature to ensure accurate and consistent colors across different lighting conditions.
- Contrast Ratio
- The contrast ratio represents the difference between a screen's darkest and brightest colors. Specifically, it is the ratio of the luminance of the brightest color (white) to that of the darkest color (black). A higher contrast ratio typically indicates a TV's ability to display a wider range of brightness levels, leading to a more detailed and vibrant picture. We usually express contrast as a ratio, such as 2000:1, where the first number is the white's brightness and the second is the black's brightness. OLED TVs have an infinite contrast ratio because they can achieve absolute black levels, measured at zero luminance. However, real-world conditions can reduce a display's contrast. Ambient light washes out the image on TVs in bright rooms, preventing them from achieving their full measured contrast ratio. So, the contrast ratio matters most for movie viewing in darkened rooms. Therefore, don't rely on the numbers alone, as they may not reflect the contrast perceived in practice.
- Display Lag
- Display lag is the delay between receiving and displaying a source signal on a screen, such as a TV, monitor, or projector. This lag can arise from various factors, including image processing, refresh rates, signal conversion, and connection methods. A low display lag of less than 30 ms ensures swift visuals and is vital for gaming activities. High display lag can disrupt experiences, causing mismatches between sound and visuals or affecting real-time interactions. Using settings like "Game Mode" can reduce such delays for optimal performance.
- DLP (Digital Light Processing)
- Digital Light Processing (DLP) is a video technology developed by Texas Instruments and used in various display systems. It is widely used in manufacturing home theater and professional projectors and sometimes in rear-projection TVs. DLP creates an image by projecting light onto a matrix of tiny mirrors. The benefits include a sharp resolution, fast response times for smooth video, excellent color accuracy, and high brightness for home theater environments.
- Dynamic Iris
- A dynamic iris is a feature in some projectors that improves the image's contrast and black level. It works by adjusting the amount of light passing through the lens based on the projected image's brightness. This feature helps create more realistic and immersive movie experiences. However, not all projectors have a dynamic iris, and its usefulness depends on your room's lighting conditions and screen size.
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- Fan Noise
- Fan noise refers to the sound that comes from the cooling fan in a projector. Some projectors have quieter fans or offer a "quiet mode" to reduce fan noise, while others may have louder fans that you cannot adjust. Fan noise can be distracting during quiet moments of a movie or video game, so it's essential to consider the noise level of a projector's fan when buying a projector.
- Foot-lamberts are a unit of measurement for the brightness of a projected image on a screen. It tells you how much light is reflected from a 1-foot by 1-foot area of the screen and is helpful as a guide to the required amount of light in different viewing conditions.
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- HDR (High Dynamic Range)
- HDR is a technique that increases the dynamic range of an image, resulting in darker blacks, brighter whites and more colors. So, HDR produces more lifelike images. There are different versions of HDR, such as HDR10, HDR10+, Hybrid Log-Gamma and Dolby Vision. Your complete hardware chain (player, receiver, TV or projector) must support a particular version for it to work.
- Image Processing
- Image processing in a projector refers to the various techniques used to enhance the picture quality of the projected image. These techniques can include adjusting the color, contrast, sharpness, and other elements of the image to improve its clarity and overall appearance. Image processing aims to produce a clear, vibrant, and realistic picture on the screen, which can significantly enhance the viewing experience. Consider the image processing features of a projector before buying if you like to fine-tune what you see.
- Image Resolution (Video Resolution)
- Image resolution, or video resolution, refers to the number of pixels used to create a digital picture measured by pixel columns horizontally and rows vertically. Higher resolutions have more pixels and provide more detail, sharper images, and smoother text. Full HD 1080p uses 1920 x 1080 pixels, while 4K Ultra HD jumps to 3840 x 2160 pixels for even crisper image quality. Matching the video resolution with the native resolution of the display ensures clear, highly detailed images without blurriness or excessive processing.
- Input Ports
- Input ports on a TV, AV receiver or projector are the physical connections that allow you to connect different devices, such as a laptop, gaming console, or Blu-ray player. The most common input ports are HDMI, optical audio, VGA, and USB. However, other types of ports may also be available, like component and composite video. The more input ports a device has, the more devices you can connect to it simultaneously, making it more versatile and convenient to use.
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- Keystone Correction
- Keystone correction is a feature in projectors that helps to fix the distortion that occurs when the projector is not placed directly in front of the screen or is tilted upwards or downwards. It adjusts the image to make it rectangular and proportional to the screen. This feature is useful when there is limited space to position the projector or the screen is at a different height than the projector. Keystone correction can be done manually or automatically through the projector's settings.
- Lamp Life
- Lamp life indicates how many hours a projector's light source will last before needing replacement. Quality lamps in well-maintained projectors can operate for thousands of hours without dimming or distortion. Cheaper lamps degrade faster, producing gradually worsening image brightness and color accuracy. Keeping track of a projector's lamp life in the settings menu is vital, as a failing lamp can lead to dimming, color distortion, or even complete failure. Before buying a projector, consider the expected lamp life to ensure you won't have to change expensive bulbs frequently.
- LCD Projector
- LCD stands for Liquid Crystal Display, a technology some projectors use to create images. LCD projectors shine a bright light source through panels containing millions of liquid crystal pixels. Each tiny pixel manipulates the light passing through, producing different colors and shades. LCD controls light efficiently to generate bright, vivid images with excellent color accuracy. Fast response times also make LCD technology well-suited for gaming and motion video. An LCD's brightness, clarity, and speed produce realistic projected images.
- LCoS (Liquid Crystal On Silicon)
- LCoS, or Liquid Crystal On Silicon, is a display technology that uses liquid crystal layers placed on top of a silicon backplane. LCoS is often found in high-end projectors due to its ability to deliver sharp, high-resolution images with good color accuracy and less visible pixel structure than many other projection technologies. LCoS is similar to DLP projection technology, which uses mirrors rather than coated silicon chips.
- Lens Memory
- Lens memory is a feature in some high-end projectors, allowing users to save different zoom and focus settings for various aspect ratios and screen sizes. With lens memory, users can easily switch between different aspect ratios (such as 16:9 and 2.35:1) without manually adjusting the zoom and focus every time. This feature is handy for home theater enthusiasts who regularly play content with different aspect ratios.
- Lens Shift
- Lens shift refers to a projector's ability to adjust the lens's position and move the projected image up, down, left or right. This movement allows you to place the projector off-center and still cast a straight, aligned image onto the screen. Lens shifting avoids keystone distortion or other image distortions caused by projecting at an angle.
- Letterboxing is caused by displaying a widescreen image on a screen with a different aspect ratio, resulting in black bars appearing at the top and bottom of the image. The bars ensure the image appears in its correct aspect ratio without being stretched or distorted. For example, suppose you watch a 16:9 widescreen movie on a traditional 4:3 aspect ratio projector or TV screen. In that case, black bars will appear at the top and bottom of the screen to maintain the original widescreen aspect ratio of the movie.
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- Native Resolution (Display Resolution)
- The native resolution, also called the display resolution, is the fixed number of pixels a display device contains, like a TV, monitor, or projector. People also refer to it as the pixel dimension. You express the native resolution by counting the number of horizontal pixels followed by the number of vertical pixels. For example, a screen with a native resolution of 1920 x 1080 has 1920 pixels across and 1080 pixels down. Generally, a screen with more pixels offers a sharper image. A display's native resolution doesn't change and is not the same as the image resolution.
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- Picture-in-Picture (PiP)
- Picture-in-Picture is a feature that simultaneously displays two different images or video sources on the same screen. It is like having two separate windows or screens overlaid on each other, one smaller than the other. PiP can be helpful for presentations, gaming, or watching multiple video sources simultaneously. It's not a common feature, but some TVs and projectors have a built-in PiP feature, so look out for this if you think it's something you'll need.
- A pixel, short for 'picture element,' is the smallest individual unit of a digital image or display. Each pixel can display various colors and brightness levels, and when viewed from a distance, you will see a complete picture made from thousands of pixels. You will see the individual pixels at work if you get very close to your television. The more pixels a screen or image has, typically indicated by its resolution (like 1080p or 4K), the more detailed and clearer the displayed picture will be. The total number of pixels that make up your TV screen is the native resolution.
- Pixel Shift
- Pixel shift is a technology used by some projectors to enhance the resolution of the projected image. It works by rapidly shifting the position of pixels in a diagonal direction by a small distance, creating a higher-resolution image than the projector's native resolution. Pixel shift can result in a clearer and more detailed picture.
- Progressive Scan
- Progressive scan displays a video image by drawing each line sequentially, providing a smoother and clearer picture. Progressive scan offers superior image quality compared to interlaced video, especially noticeable when watching movies or playing video games, as it eliminates flicker and provides sharper details. Modern flat-screen TVs use progressive scan images and must deinterlace any older interlaced video images they receive.
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- Refresh Rate
- Refresh rate refers to the number of times per second a TV or monitor updates its screen. A higher refresh rate can result in smoother motion, especially for action movies or sports. Until recently, the standard refresh rate for a TV was 50 or 60 Hz, depending on where you are. However, modern screens now support native refresh rates of 100 or 120 Hz, which benefits UHD screens with HDR pictures. Some models claim even higher refresh rates by using digital signal processing. But these inflated numbers aren't the actual refresh rate of the television.
- Screen Gain
- Screen gain is the amount of light a projector screen reflects compared to a flat white surface. A higher screen gain reflects more light at the viewer, resulting in a brighter and more vibrant image. A high screen gain can be handy in rooms with plenty of ambient light, which may otherwise wash out the projected image. However, higher screen gain may also result in more visible texture or "hot spotting" on the screen, so it may not be suitable for all viewing environments.
- Short Throw Projector
- A short throw projector can produce a large projected image while positioned very close to the screen or wall, usually less than 4 feet away. The specialized lens requires less distance to spread light for a given screen size than a standard projector. Short throw models are ideal for smaller rooms with limited space where you can't install a traditional standard throw projector. Their extreme wide-angle projection capabilities are perfect for large images in tight spaces. If you want to install a projector even closer, consider an ultra-short throw projector.
- Standard Throw Projector
- A standard throw projector must be quite far from the screen to project a good-sized image. The distance required for a standard throw projector is typically 1.5 to 2 times the screen's width, meaning the projector would have a throw ratio of 1.5:1 or 2:1. They are suitable for large rooms or outdoor spaces requiring a larger image size.
- Throw Distance
- The throw distance is the length you need between the projector and the screen to display a specific image size. This distance depends on the lens used and the ideal width of the image. Knowing the throw distance is essential when purchasing a projector, as it indicates how far away you need to install it. You can calculate the throw distance by multiplying the throw ratio of a projector by the width of the image you need.
- Throw Ratio
- A projector's throw ratio is the relationship between projection distance and image size. It represents how many units of throw distance you need per unit of projected image width. Lower throw ratios enable you to place the projector closer to the screen. High throw ratios require more space but allow larger image sizes. When selecting a projector, match its throw ratio range to the planned screen size and room layout to ensure you can achieve the required projection distance.
- Ultra-Short Throw Projector (UST)
- An ultra-short throw projector can produce a large image from a very short distance from the screen or wall. Ultra-short throw projectors are becoming popular in home theaters because they can provide a sizeable cinematic image even in a small room, and you don't have to run wires everywhere. The typical throw ratio for a UST projector is less than 0.4:1. However, the specific throw ratio for a UST projector will vary depending on the model and manufacturer. A typical UST projector with a throw ratio of 0.25:1 can project a 100-inch diagonal image from just 25 inches away from the screen.
- Uniformity refers to the consistency of brightness and color across a projected image or TV picture. A picture with good uniformity will display an even and consistent image without noticeable variations in luminance or color in different screen areas. Poor uniformity can lead to distracting "hotspots" or "cold spots" in the picture, diminishing the overall viewing experience.
- VGA Connector
- A VGA connector is a traditional 15-pin D-type video connection primarily designed for connecting computers to monitors. However, VGA can also link computers or legacy video equipment to projectors or HDTVs. Unlike modern digital connectors like HDMI, VGA is an analog interface and does not transmit audio. Therefore, while it provides video to a home theater display, users need a separate audio connection. As technology has advanced, HDMI, capable of transmitting high-definition video and audio over a single cable, has predominantly replaced VGA.
- Wide Color Gamut
- The Wide Color Gamut (WCG) is a spectrum of colors that exceeds the standard color spectrum used by conventional displays. With the introduction of the 4K Ultra HD specification, the BT.2020 standard emerged, expanding the scope of available colors. Through WCG, screens can depict a more expansive and lifelike array of colors, rendering images with heightened realism and vibrancy.
- Wireless Connectivity
- Wireless connectivity lets devices like projectors and amplifiers receive audio/video signals without cables. Technologies like Wi-Fi, Bluetooth, AirPlay, and Chromecast transmit signals between source devices and displays without wires. Going wireless provides greater setup flexibility and eliminates messy cables between components. It allows seamless streaming from phones, PCs, and media boxes to speakers, TVs, and projectors anywhere in a room.
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- A projector's zoom controls let users resize a projected image without moving the unit. Zoom adjusts the lens's focal length to widen or narrow the beam. Manual zoom uses a dial or lever to manipulate the lens. Motorized zoom provides electronic control through remotes or on-screen menus to optimize screen size. For home theater use, look for zoom ratios between 1.3x and 1.8x. This range allows 30-80% image enlargement, providing flexibility without unnecessary maximum zoom capabilities that add cost.
- Zoom Lens
- A zoom lens adjusts the image size by physically zooming in or out without moving the projector. Budget or portable projectors may have fixed focus lenses with no zoom (1x). A budget zoom lens may zoom 1.1x to 1.3x, allowing a 10 to 30% enlargement. 1.3x to 1.5x allows a 30 to 50% enlargement, while higher-end home theater projectors usually offer 1.5x to 2.0x zoom (50 to 100% bigger).
About The Author
Paul started the Home Cinema Guide to help less-experienced users get the most out of today's audio-visual technology. He has been a sound, lighting and audio-visual engineer for around 20 years. At home, he has spent more time than is probably healthy installing, configuring, testing, de-rigging, fixing, tweaking, re-installing again (and sometimes using) various pieces of hi-fi and home cinema equipment. You can find out more here.