The basics of a sound system installation: connections, cables, connectors and practical advice

A good audio setup doesn't just depend on the equipment: the cabling makes all the difference. Bad connections, poor cables, interference... and your sound becomes flat, or even inaudible. This guide gives you the technical basics to understand, connect and optimise your setup, whether it's for a party, an event or a home installation.

Understanding inputs (IN) and outputs (OUT)

• IN (input): where the signal arrives (e.g. a speaker receives a signal from a mixing desk).
• OUT (output): where the signal leaves (e.g. an audio output on a phone or mixing desk).

Simple example:

• OUT output from your smartphone → IN input from your speaker (via mini-jack cable).

Always connect in the correct direction. Reversing IN and OUT can result in no sound or damage to the equipment.

Mono vs Stereo: the essential difference

• Mono cable: transmits a single audio channel. Used for instruments, microphones, or certain professional connections (XLR, mono jack).
• Stereo cable: transmits two audio channels (left and right). Essential for listening to music with spatialisation.

How can you tell them apart?

• Mono jack: a single black stripe on the plug
• Stereo jack: two black stripes

Tip: for a wide sound system, stereo is often preferable. For an instrument → mixer → speaker connection, mono is often sufficient.

Types of cables and their uses

1. Jack cable (6.35 mm or 3.5 mm)

• Use: instruments (guitar, keyboard), headphone outputs, short audio connections.
• Mono or stereo depending on the configuration.
• Ideal length: < 5 m. Beyond this, signal loss is possible without amplification.

2. XLR cable

• Use: microphones, connections between mixer and speaker.
• Professional quality: balanced signal that prevents interference.
• Long distance (up to 30 m without loss).

3. RCA cable (red and white)

• Use: CD players, turntables, old Hi-Fi equipment.
• Susceptible to interference. Recommended length < 10 m.

4. Speakon cable

• Use: connection between passive speaker ↔ amplifier.
• Secure locking, very reliable, no loss.
• Reserved for power transmission (not audio signal).

5. Optical cable (TOSLINK)

• Use: home cinema, lossless digital connections.
• Not sensitive to interference, but physically fragile.

Choosing cables according to distance

• Less than 5 metres: jack, RCA or XLR possible.
• Between 5 and 20 metres: opt for XLR or Speakon.
• Over 20 metres: use XLR or install a professional wireless transmission system.

Long cables must have a sufficient cross-section (2x1.5 mm² or 2x2.5 mm²) to avoid power loss.

Connector quality: a detail that makes all the difference

• Gold-plated: better conductivity, oxidation resistance (often found in mini-jack or premium RCA connectors).
• Nickel: standard, sufficient for occasional use.
• Moulded or screw-on connectors: choose screw-on connectors for easy repair.

Tip: never neglect adapters. A bad adapter can ruin your entire audio system.

Bluetooth vs cable: sound quality and interference

Cable:

• Advantage: consistent quality, no audio compression.
• Disadvantage: visible cables, less convenient.

Bluetooth:

• Advantage: flexibility, no cables.
• Disadvantage: signal compression, possible latency, interference (microwaves, Wi-Fi).

For maximum quality, always opt for a wired connection, especially at events or live performances.

Common problems to avoid

• Buzz or hum: ground loop → use balanced cables (XLR).
• Signal loss: cable too long or of poor quality.
• No sound at all: output connected to another output (OUT to OUT instead of OUT to IN).