Low-cost HDMI accessories extend signals across rooms and floors

The problem is attenuation: HDMI signals weaken as they travel. It becomes particularly noticeable when cables run further than 25 feet, and long-distance HDMI setups can suffer from audio loss or a complete signal drop. Most home setups can avoid the risk with shorter, high quality cables, but multiple screens, a television on the back porch or meetings between conference rooms may require additional hardware.

HDMI couplers extend a setup by linking two HDMI cables. They look like a small box with two HDMI ports, or female sockets, on either end. The male connector ends of two HDMI cables plug into the female sockets, and the coupler carries the signal from one cord to the other. Couplers add reach without much data loss, cost less than most long-distance cables, and many support 8K video and up to 48 Gbps of bandwidth, roughly the specifications of HDMI 2.1. Engadget said this option has helped with outdoor movie nights when an outdoor projector's HDMI connection needed to be extended.

Couplers have limits. Because HDMI signals weaken as they travel, relying on a coupler to relay a string of HDMI cables beyond 25 feet can still cause signal degradation. Replacing older HDMI cables with newer Ultra High Speed alternatives can create additional issues, since newer cable standards have a shorter effective length and the coupler must support the newer standard. An HDMI coupler may therefore be impractical for users who prioritize speed and maximum quality.

Signal repeaters address longer runs. Like a coupler, a repeater is a small box with two female HDMI ports used to link two cables, but it refreshes the signal rather than simply passing it along. A typical repeater can extend an HDMI signal to around 100 feet. Linking several HDMI cables together via repeaters can boost a signal across an office, classroom or outdoor patio, though long chains may not be aesthetically pleasing. The main downside is price. A single repeater can cost as low as $20, but stringing multiple together can quickly raise costs. A repeater may not be ideal for linking multiple rooms, but two or three repeaters could still cost less than more advanced accessories.

Active cables are another option. The latest HDMI cables are more susceptible to signal degradation, with many seeing attenuation after 9 feet. Active cables contain small chips within the wiring to boost the signal. There are two major forms: copper and fiber optic. Copper active cables use signal repeaters within the wiring and sometimes reach over 100 feet. Fiber optic cables contain thin glass fibers that transmit signals through pulses of light, similar to what an internet service provider may provide for home internet. Fiber optic HDMI cables are suited to large spaces, with some reaching over 300 feet.

Active cables require more intentional setup. Passive cables can send signals in either direction, but active cables carry signals unidirectionally. They are also not compatible with all devices. Some Ultra High Speed cables contain their own internal power systems, so users need to confirm that a device supports HDMI cable power before buying an active HDMI option. Cost is another factor. Copper cables can cost between $35 and $80 depending on length and brand, while fiber optic cables might cost between $40 and $120. Most situations do not warrant expensive HDMI products, but an active cable can save users from buying an ever-growing pile of additional accessories.