Parameters of Audio and Video Cables

The parameters of audio and video cables directly affect signal transmission quality (e.g., sound quality, image quality), stability, and applicable scenarios. Understanding these parameters helps select cables that match device requirements, avoiding performance waste or signal loss. Below is a detailed explanation from three dimensions: general parameters, exclusive parameters for audio cables, and exclusive parameters for video cables:

I. General Parameters (Common to Both Audio and Video Cables)

These parameters determine the basic performance and applicable environment of the cable:

1. Cable Length

   • Core impact: Too short a length limits device placement distance; excessive length may cause signal attenuation (especially significant for analog signals) and increased latency.

   • Reference standards:

     • Analog cables (e.g., 3.5mm, VGA) are recommended to be ≤5 meters; signal amplifiers are required for longer lengths.

     • Digital cables (e.g., HDMI, optical fiber) can support longer distances (ordinary HDMI ≤10 meters, fiber-optic HDMI up to 50+ meters).

2. Conductor Material and Specification

   • Material: Common materials include oxygen-free copper (high purity, good conductivity, low signal loss). High-end cables may use silver-plated copper (enhanced conductivity and oxidation resistance) or optical fiber (exclusive for digital signals, no electromagnetic interference).

   • Wire gauge: Diameter of the conductor cross-section (unit: mm). Larger wire gauges (e.g., 24AWG is thicker than 28AWG) reduce signal transmission loss, making them suitable for long-distance transmission.

3. Shielding Design

   • Function: Reduces external electromagnetic interference (EMI) and radio frequency interference (RFI), preventing signal noise or image snow.

   • Common types:

     • Foil shielding (single/double layer): Basic anti-interference, suitable for general scenarios.

     • Braided shielding (copper mesh, higher coverage is better): Enhanced anti-interference, suitable for complex electromagnetic environments (e.g., stages, equipment rooms).

     • Double-layer shielding (foil + braid): Professional-grade anti-interference, used for high-end audio equipment or long-distance transmission.

4. Connector Type and Craftsmanship

   • Connector type: Must match the device (e.g., HDMI, 3.5mm, XLR), determining physical connection compatibility.

   • Connector craftsmanship:

     • Gold-plated connectors: Enhance conductivity, resist oxidation, and extend plug-in lifespan.

     • Integrated injection molding: Strengthens the connection between the connector and cable, preventing breakage from pulling.

II. Exclusive Parameters for Audio Cables

Affect sound purity, dynamic range, and transmission stability:

1. Signal Type (Analog/Digital)

   • Analog cables: Require attention to impedance matching (e.g., microphone cables are typically 600Ω). Mismatched impedance causes signal attenuation or distortion.

   • Digital cables: Must support corresponding audio formats (e.g., optical cables need to support Dolby Atmos, DTS-HD; coaxial cables must be compatible with the SPDIF protocol).

2. Balanced/Unbalanced Transmission

   • Balanced transmission (e.g., XLR cables): Uses a 3-core design ("hot + cold + ground") to cancel interference signals, suitable for long-distance transmission (e.g., from stage microphones to mixers) with purer sound.

   • Unbalanced transmission (e.g., 3.5mm, RCA cables): Only has 2 cores ("signal + ground"), with weak anti-interference, suitable for short distances (e.g., headphone cables, home audio).

3. Bandwidth (Digital Audio)

   • Unit: Mbps. Higher bandwidth supports larger audio bitrates (e.g., lossless audio). For example, optical cables typically have a bandwidth ≥25Mbps, covering most high-definition audio formats.

III. Exclusive Parameters for Video Cables

Determine core performance such as image resolution, refresh rate, and color depth:

1. Resolution Support

   • Refers to the maximum image resolution the cable can transmit (e.g., 1080p, 4K, 8K), which must match the device (e.g., TV, graphics card).

   • Examples:

     • HDMI 1.4 supports 4K@30Hz;

     • HDMI 2.1 supports 8K@60Hz or 4K@120Hz;

     • DP 1.4 supports 8K@60Hz, and DP 2.0 supports 16K@60Hz.

2. Refresh Rate (Hz)

   • Unit: Hz, indicating the number of frames transmitted per second, affecting the smoothness of dynamic images (e.g., games, sports events).

   • High refresh rates depend on cable bandwidth: HDMI 2.1 supports 4K@120Hz and 1080p@240Hz; DP cables generally support higher refresh rates (e.g., 2K@240Hz).

3. Bandwidth (Digital Video)

   • Unit: Gbps, a core parameter determining the limits of resolution, refresh rate, and color depth.

   • Examples:

     • HDMI 2.0 has a bandwidth of 18Gbps, supporting 4K@60Hz (8-bit color);

     • HDMI 2.1 increases bandwidth to 48Gbps, supporting 8K@60Hz (10-bit color) + HDR;

     • DP 1.4 has a bandwidth of 25.92Gbps, and DP 2.0 reaches 80Gbps.

4. Color Depth and HDR Support

   • Color depth: Refers to the color information per pixel (e.g., 8-bit, 10-bit, 12-bit). 10-bit displays over 1 billion more colors than 8-bit, requiring sufficient cable bandwidth.

   • HDR (High Dynamic Range): Cables must be compatible with protocols like HDR10 and Dolby Vision (e.g., HDMI 2.0+, DP 1.4+); otherwise, HDR signals cannot be transmitted.

5. Copy Protection Protocol

   • e.g., HDMI’s HDCP (High-bandwidth Digital Content Protection) prevents piracy. Cables must support corresponding versions (e.g., HDCP 2.2 for 4K content, HDCP 2.3 for 8K content); otherwise, black screens or reduced quality may occur.