Digital Audio Cables
A digital cable carries a bitstream; wrong impedance or length raises error rates and the sound turns unstable.
Related
The problem
A digital cable looks much like an analogue one, but it does a different job. It carries a bitstream of sample points, and wrong impedance, excessive length or oxidised connectors can make the receiver misread positions, losing lock outright or producing occasional clicks and high-frequency grit. Digital is not simply working or broken; it has in-between states.
How it works
AES3 runs on 110-ohm balanced cable, coaxial S/PDIF on 75 ohm, and optical links on plastic or glass fibre. Impedance mismatches reflect at connectors, blunting square-wave edges and narrowing the receiver's sampling window. Clock and audio data share the same stream, so errors hit both. Over distance, attenuation and jitter accumulate, and runs beyond a few tens of metres call for redistribution or fibre. Fibre ignores electromagnetic interference but leaks light if bent too tightly.
Settings and practice
Use 75-ohm video or dedicated digital cable for coax rather than microphone cable. Use 110-ohm twisted pair for balanced AES3 and keep solder joints solid. Keep optical connectors clean and leave slack at bends. Do not coil cable into tight loops; coil surplus loosely. Troubleshoot a digital chain from the shortest link outward, swapping cable and port first. For long runs, use a distribution amplifier or a networked audio protocol.
What to listen for
On the funk kit cymbals, listen for occasional fine-grained noise; on the Debussy chords, for roughness in the top; on the organ, for steadiness in long notes. Digital faults are often intermittent and easier to hear in quiet passages.
Listen in the library
All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).
Sources
- AES3 与 S/PDIF 的阻抗与电平差异，依公开标准说明核对，未抄原文
- 数字线缆长度对误码的影响，依接口厂商技术资料核对，未抄文本
Used for fact-checking only; all prose is original.