Speakon to Speakon Cable: Pinout, Gauge and Length

A Speakon to Speakon cable is the standard link between a professional amplifier and a passive loudspeaker. Both ends lock, both ends carry the same four-pole shell, and the only variables are the pin assignment, the gauge and the length. That sounds simple until a cable wired for 1+ and 1- is plugged into a bridged amplifier that expects 1+ and 2+, or an NL2 plug is forced into a four-pole socket. Checking three details before ordering prevents both.

When Both Ends Are Speakon

Amplifiers and powered mixers with Speakon outputs expect a Speakon cable, and passive cabinets with Speakon sockets expect the same at the other end. Using a Speakon to 1/4 inch adapter defeats the locking and current advantages, so a cable with the correct shell at each end is the better purchase. The two ends are electrically identical; only the pin assignment and the shell keying need to match the equipment.

NL2 into NL4 Sockets

An NL2 plug will enter an NL4 socket and use 1+ and 1-. That is acceptable for a single speaker run, but the cable cannot carry a bi-amp signal. If the amplifier or cabinet is four-pole, buy a four-pole cable so the option remains.

Shell Orientation

The keyway prevents incorrect insertion. Do not force a connector that will not seat; check the key and the socket for damage. A connector that turns only part way is not locked and can arc under load.

Pin Assignment and Bridged Operation

The common wiring is 1+ to the positive terminal and 1- to the negative at both ends. Some amplifiers in bridged mode use 1+ and 2+ for the output, which requires a four-pole cable and a matching plug at the cabinet. Bi-amped cabinets use 1+/1- for the low section and 2+/2- for the high section. The assignment is set by the equipment manual, not by the cable, so a cable built for one system may be wrong for another.

Standard Stereo Wiring

For a single cab on a single channel, 1+ and 1- is universal. Both conductors should be the same gauge and length. Leave 2+ and 2- unconnected unless the system uses them, and do not let the unused conductors short to the shell.

Bridged and Bi-Amp Wiring

Bridged outputs often use 1+ and 2+, so a cable with only 1+ and 1- will not work. Bi-amp cabinets use all four poles. Label the cable with the exact assignment and keep it with that system, because a miswired four-pole cable can send a full-range signal to a horn.

Gauge and Length

For most PA and bass cabinets, 14 AWG is the practical default and 12 AWG is used for long runs or high current. The loop resistance of 14 AWG is about 0.33 ohm over 20 m, which is noticeable on a 4 ohm load and small on 8 ohm. Keep the cable as short as the stage allows, coil excess loosely rather than tightly, and avoid running it parallel to mains cables for long distances.

Matching Gauge to the Cabinet

A 200 W 8 ohm cabinet on a 5 m run is fine with 16 AWG, but 14 AWG gives margin. A 1000 W 4 ohm subwoofer on a 15 m run needs 12 AWG. The cable should never be the weakest link in the power path.

Coiling and Heat

A tightly coiled cable carrying high current can warm up because the coil traps heat. Lay excess cable in a loose figure eight. Do not coil it around a metal case or across a power supply vent.

Buying and Testing

Buy pre-made cables with moulded or screwed connectors and a strain relief boot. Check that the pins are labelled and that the boots grip the jacket. On arrival, test continuity pin by pin and check for shorts between adjacent pins. Then connect a known good cabinet and listen at low level before applying full power. A cable that passes a meter can still fail under vibration, so flex the ends while listening.

Pre-Made vs Custom

Pre-made cables are consistent and cheap in common lengths. Custom lengths suit fixed installs where a 7 m cable is needed and a 10 m cable would leave a coil. Use the same connector series at both ends.

Bench Test

Check 1+ to 1- for continuity, then 2+ to 2- if fitted, then each pin to every other pin for a short. A short between 1+ and 2+ may only appear when the connector is twisted, so test with the shell fitted.

Speakon to Speakon cable configurations

Real-World Application Scenarios

A touring band keeps four 10 m NL4 cables wired 1+/1- for its wedges and two 5 m four-core cables for bi-amped monitors, labelled by colour. A church installs a 12 m 12 AWG cable from a rack amplifier to a ceiling subwoofer and labels the bridged pins at both ends. A rehearsal room uses 3 m 14 AWG cables so the amplifiers can sit beside the cabinets instead of across the room.

Related Guides on This Site

For connector background, read the Speakon cable guide and the PA system speaker cable guide. Buying pre-made against bulk is compared in speaker cable bulk vs premade, and gauge selection in the 12 gauge engineering guide.

Frequently Asked Questions (FAQ)