Comparing Video Cable Quality
Comparing Video Cable Quality
Q: Why are some video cables so expensive? Do they improve video quality?
A: Because many cable shoppers assume higher prices mean better performance many cable companies meet their assumption and sell them very profitable cables. Instead of providing superior electrical specifications or test data, many of these companies use fancy photos, elaborate descriptions and confusing technical terms to persuade cable shoppers.
Q: Can some video cables "improve" video performance?
A: No. Video cables simply carry a signal and should NOT try to improve performance. Ideally, the perfect video cable would simply move a video signal from one end to the other unchanged. In the case of composite video, component video, s-video, RGB & RGBHV video, the cable's ability to accurately transmit a video signal depends primarily on its ability to preserve an accurate 75-ohm signal from end to end. Among other factors, accurate impedance of 75 ohms is most commonly degraded by return loss (RL). RL occurs when signals bounce back to the video source and is caused by irregularities along the cable and cable-to-connector mismatches. Although a cable cannot "improve" performance, it can degrade performance when low quality cables are used, especially over longer distances.
Q: What are THX certified cables?
A: The term "THX" is a trade name of a high-fidelity SOUND system, not a VIDEO system. Other cable companies have purchased THX certification to aid in the selling of cables, but A2Z Cables has not. Instead of relying on certifications to sell cables, A2Z Cables has chosen to focus on selling cables that meet or exceed the electrical specifications of their intended purpose.
Q: Are thick conductors better?
A: Emphasis on conductor size is often used to convince cable shoppers that "more is better" and results in the waste of enormous amounts of copper. Generally, thick conductors are used for very long (outdoor) cable runs, but such thick conductors are overkill indoors. Over standard indoor cabling distances (up to about 150 feet) you will find that high quality video cables with thin conductors will perform just as well as cables with thick conductors. The reason is that there is not enough signal degradation at such short distances. Instead of relying on "more is better" to sell cables, A2Z Cables has chosen to focus on selling cables that meet or exceed the electrical specifications of their intended purpose.
Q: How important is shielding in video cables?
A: Shielding in video cables prevents external interference from degrading your video signal within the cable. Most shielding consists of foil and/or copper braid, and some cables use both. A common problem in low-grade cable is the lack of shield density or uniformity of their copper braid shielding, an arrangment that leaves big gaps for interference.
Q: What are back-reflections?
A: Back-reflections occur in cables wherever there are variations in impedance (measured in ohms). Back-reflections degrade video signal integrity and commonly occur within low grade cable (due to structural variations throughout the cable) and where cable and connector meet.
Q: What matters most in a cable's ability to carry a video signal accurately?
A: Tight control over the cable's impedance from end to end is the most important factor in "analog" video signal accuracy. Analog video signals are the kind used in composite video, component video, s-video, RGB and RGBHV video. Keeping the impedance as close as possible to 75 ohms is the key to a complete signal. Low-grade cables will claim 75 ohms or a "nominal" impedance of 75 ohms but may go as far as 20 ohms above or below 75 ohms.
Q: What is the difference between "stranded" and "solid" conductors?
A: Solid conductors are less flexible but provide superior control over impedance. The reason for this is that solid conductors have smooth surfaces that allow more consistant spacing between the conductor and its shield/ground, and this is what determines accurate 75-ohm impedance. The only benefit of stranded conductors is that they are more flexible and better suited to applications where the cable will be constantly moved around.
Q: What is the difference between soldered connectors and crimp connectors in video cables?
A: Soldered connectors are the preferred way to terminate "audio" cables, but not for analog video cables (which includes composite video, component video, s-video, RGB and RGBHV video). Especially in HDTV video transmission, high-bandwidth and crimp-on connectors are preferred because they retain the electro-mechanical relationship between a coaxial cable's conductor and shield (ground) and this determines the accuracy of the impedance (measured in ohms). Soldering connectors onto cables used for HDTV creates an impedance mismatch (or bottleneck) that results in back-reflections inside the cable, and this negatively effects signal quality and decreases bandwidth.
Q: I see that some cables have silver conductors. Does that make a difference in video quality?
A: Claims that conductors are "silver", "100% silver", "pure silver" or "silver plated" are usually a marketing game with the word "silver" (a color). The coating found on most conductors is actually tin, and tin is actually BETTER THAN silver as a coating. Silver might sound more attractive, but tin coating keeps electron-flow inside the copper conductor (because it is more resistent than copper) and protects the copper from oxidation. In addition, none of the major manufacturers of video cable spools use silver in their video cable conductors because nothing is to be gained by it.
Q: I see that some connectors feature gold contacts. Does that make a difference in video quality?
A: A lot of people are surprised to hear that gold or nickel plating makes no difference at all when it comes to video quality. In truth, the use of gold plating in connector contacts is mostly driven by marketing and appearance. Keep in mind that most video signals travel through a combination of copper, lead, tin, silver, brass, aluminum, nickel or gold (or mixes thereof) before completing their journey.
Q: What is the difference between analog video cables and digital video cables?
A: Basically, analog video signals travel in the form of waves, and digital video signals travel in the form of 1's and 0's or ONs and OFFs. Many customers believe digital transmission is superior, but both digital and analog can have transmission errors. However, digital transmission errors result in total signal loss, but analog transmission has error-correcting technology which can repair signal errors. Over longer distances, especially beyond 25 feet, analog video has proven to be more reliable.
Q: What is Oxygen-Free Copper or OFC copper?
A: Oxygen-free copper (OFC) is copper that has been manufactured in an oxygen-free atmosphere. The reason for this is to reduce oxidation of the copper (as when copper turns green over very long periods of time). However, even very old cables have little or no noticable oxidation inside of them because they are sealed inside the cable. As far as video quality goes, oxygen-free copper conductors or shields perform no differently than standard or tinned copper conductors. A better way to prevent oxidation is to use tinned copper (copper coated with tin).
Q: What is Nominal Attenuation?
A: Nominal attenuation is a measure of signal strength over a given distance (usually 100 feet) at a certain frequency (MHz). A loss in signal strength doesn't necessarily degrade video quality because the circuitry in your display can adjust for a certain amount of signal loss.
Q: What is the difference between mass-production cables and cable assemblies?
A: Mass-production cables are usually produced in very large quantities overseas and then distributed through many levels (importer - wholesaler - distributor - retailer) before being bought. Each level takes profit so the focus is on producing cables as cheaply as possible. Cable assemblies are usually assembled domestically using a length of cable and connectors. Cables can be assembled using low grade components (usually without verifiable specifications) or high grade components (usually with verifiable specifications). The quality of either cable (mass-production or assembly) depends on the specifications of the cable (that was cut from a spool), connector type and quality, and termination quality. Determining the quality of mass-production cables is often difficult because the specifications of the cable used is not released and connectors are often glued or injection molded (so termination quality cannot be inspected).
Q: My video port has some funny letters on it. What do they mean?
A: Y, B-Y, R-Y or Y, Pb, Pr or Y, Cb, Cr are all component video. Y/C is s-video. VGA, RGB and/or RGBHV are usually used to describe the same type of signal but VGA is also often used to describe all computer-oriented resolutions instead of just 640x480 (original VGA).
Q: What does RGB mean?
A: RGB is known as two things in video cabling: 1. RGB can stand for "Red, Green & Blue" (which are the colors commonly used on component video cables). 2. More technically RGB is used to describe a video format that is actually called RGBHV (Red, Green & Blue with Horizontal & Vertical Sync Information). This is the video format used by most computer video ports and CRT monitors.
Related Help Articles:
Q: Why are some video cables so expensive? Do they improve video quality?
A: Because many cable shoppers assume higher prices mean better performance many cable companies meet their assumption and sell them very profitable cables. Instead of providing superior electrical specifications or test data, many of these companies use fancy photos, elaborate descriptions and confusing technical terms to persuade cable shoppers.
Q: Can some video cables "improve" video performance?
A: No. Video cables simply carry a signal and should NOT try to improve performance. Ideally, the perfect video cable would simply move a video signal from one end to the other unchanged. In the case of composite video, component video, s-video, RGB & RGBHV video, the cable's ability to accurately transmit a video signal depends primarily on its ability to preserve an accurate 75-ohm signal from end to end. Among other factors, accurate impedance of 75 ohms is most commonly degraded by return loss (RL). RL occurs when signals bounce back to the video source and is caused by irregularities along the cable and cable-to-connector mismatches. Although a cable cannot "improve" performance, it can degrade performance when low quality cables are used, especially over longer distances.
Q: What are THX certified cables?
A: The term "THX" is a trade name of a high-fidelity SOUND system, not a VIDEO system. Other cable companies have purchased THX certification to aid in the selling of cables, but A2Z Cables has not. Instead of relying on certifications to sell cables, A2Z Cables has chosen to focus on selling cables that meet or exceed the electrical specifications of their intended purpose.
Q: Are thick conductors better?
A: Emphasis on conductor size is often used to convince cable shoppers that "more is better" and results in the waste of enormous amounts of copper. Generally, thick conductors are used for very long (outdoor) cable runs, but such thick conductors are overkill indoors. Over standard indoor cabling distances (up to about 150 feet) you will find that high quality video cables with thin conductors will perform just as well as cables with thick conductors. The reason is that there is not enough signal degradation at such short distances. Instead of relying on "more is better" to sell cables, A2Z Cables has chosen to focus on selling cables that meet or exceed the electrical specifications of their intended purpose.
Q: How important is shielding in video cables?
A: Shielding in video cables prevents external interference from degrading your video signal within the cable. Most shielding consists of foil and/or copper braid, and some cables use both. A common problem in low-grade cable is the lack of shield density or uniformity of their copper braid shielding, an arrangment that leaves big gaps for interference.
Q: What are back-reflections?
A: Back-reflections occur in cables wherever there are variations in impedance (measured in ohms). Back-reflections degrade video signal integrity and commonly occur within low grade cable (due to structural variations throughout the cable) and where cable and connector meet.
Q: What matters most in a cable's ability to carry a video signal accurately?
A: Tight control over the cable's impedance from end to end is the most important factor in "analog" video signal accuracy. Analog video signals are the kind used in composite video, component video, s-video, RGB and RGBHV video. Keeping the impedance as close as possible to 75 ohms is the key to a complete signal. Low-grade cables will claim 75 ohms or a "nominal" impedance of 75 ohms but may go as far as 20 ohms above or below 75 ohms.
Q: What is the difference between "stranded" and "solid" conductors?
A: Solid conductors are less flexible but provide superior control over impedance. The reason for this is that solid conductors have smooth surfaces that allow more consistant spacing between the conductor and its shield/ground, and this is what determines accurate 75-ohm impedance. The only benefit of stranded conductors is that they are more flexible and better suited to applications where the cable will be constantly moved around.
Q: What is the difference between soldered connectors and crimp connectors in video cables?
A: Soldered connectors are the preferred way to terminate "audio" cables, but not for analog video cables (which includes composite video, component video, s-video, RGB and RGBHV video). Especially in HDTV video transmission, high-bandwidth and crimp-on connectors are preferred because they retain the electro-mechanical relationship between a coaxial cable's conductor and shield (ground) and this determines the accuracy of the impedance (measured in ohms). Soldering connectors onto cables used for HDTV creates an impedance mismatch (or bottleneck) that results in back-reflections inside the cable, and this negatively effects signal quality and decreases bandwidth.
Q: I see that some cables have silver conductors. Does that make a difference in video quality?
A: Claims that conductors are "silver", "100% silver", "pure silver" or "silver plated" are usually a marketing game with the word "silver" (a color). The coating found on most conductors is actually tin, and tin is actually BETTER THAN silver as a coating. Silver might sound more attractive, but tin coating keeps electron-flow inside the copper conductor (because it is more resistent than copper) and protects the copper from oxidation. In addition, none of the major manufacturers of video cable spools use silver in their video cable conductors because nothing is to be gained by it.
Q: I see that some connectors feature gold contacts. Does that make a difference in video quality?
A: A lot of people are surprised to hear that gold or nickel plating makes no difference at all when it comes to video quality. In truth, the use of gold plating in connector contacts is mostly driven by marketing and appearance. Keep in mind that most video signals travel through a combination of copper, lead, tin, silver, brass, aluminum, nickel or gold (or mixes thereof) before completing their journey.
Q: What is the difference between analog video cables and digital video cables?
A: Basically, analog video signals travel in the form of waves, and digital video signals travel in the form of 1's and 0's or ONs and OFFs. Many customers believe digital transmission is superior, but both digital and analog can have transmission errors. However, digital transmission errors result in total signal loss, but analog transmission has error-correcting technology which can repair signal errors. Over longer distances, especially beyond 25 feet, analog video has proven to be more reliable.
Q: What is Oxygen-Free Copper or OFC copper?
A: Oxygen-free copper (OFC) is copper that has been manufactured in an oxygen-free atmosphere. The reason for this is to reduce oxidation of the copper (as when copper turns green over very long periods of time). However, even very old cables have little or no noticable oxidation inside of them because they are sealed inside the cable. As far as video quality goes, oxygen-free copper conductors or shields perform no differently than standard or tinned copper conductors. A better way to prevent oxidation is to use tinned copper (copper coated with tin).
Q: What is Nominal Attenuation?
A: Nominal attenuation is a measure of signal strength over a given distance (usually 100 feet) at a certain frequency (MHz). A loss in signal strength doesn't necessarily degrade video quality because the circuitry in your display can adjust for a certain amount of signal loss.
Q: What is the difference between mass-production cables and cable assemblies?
A: Mass-production cables are usually produced in very large quantities overseas and then distributed through many levels (importer - wholesaler - distributor - retailer) before being bought. Each level takes profit so the focus is on producing cables as cheaply as possible. Cable assemblies are usually assembled domestically using a length of cable and connectors. Cables can be assembled using low grade components (usually without verifiable specifications) or high grade components (usually with verifiable specifications). The quality of either cable (mass-production or assembly) depends on the specifications of the cable (that was cut from a spool), connector type and quality, and termination quality. Determining the quality of mass-production cables is often difficult because the specifications of the cable used is not released and connectors are often glued or injection molded (so termination quality cannot be inspected).
Q: My video port has some funny letters on it. What do they mean?
A: Y, B-Y, R-Y or Y, Pb, Pr or Y, Cb, Cr are all component video. Y/C is s-video. VGA, RGB and/or RGBHV are usually used to describe the same type of signal but VGA is also often used to describe all computer-oriented resolutions instead of just 640x480 (original VGA).
Q: What does RGB mean?
A: RGB is known as two things in video cabling: 1. RGB can stand for "Red, Green & Blue" (which are the colors commonly used on component video cables). 2. More technically RGB is used to describe a video format that is actually called RGBHV (Red, Green & Blue with Horizontal & Vertical Sync Information). This is the video format used by most computer video ports and CRT monitors.
Related Help Articles:
