Wiring Inside the Cabinet: Gauge, Joints, and Service Loops
The wire between a crossover and a driver carries the same current as the run from the amplifier, but over a fraction of the distance. That changes the specification. Internal speaker cable is short, flexible, and often smaller in gauge than the cable feeding the cabinet. Getting it right is about joint quality and mechanical layout rather than exotic materials.
Quick Answer / Summary
Internal speaker cable inside a cabinet is typically 16 to 18 AWG, chosen for current capacity, flexibility, and fit around drivers. Keep runs short, twist conductor pairs where practical, make gas-tight solder or crimp joints, and leave a service loop long enough to remove a driver without stressing the wire. Secure the cable so it cannot touch a cone or rattle.
Why 16 to 18 AWG Covers Most Cabinets
Internal runs are short, usually under three feet. Resistance scales with length, so a short run of 18 AWG adds only a small fraction of an ohm, well inside the 5 percent loop resistance guideline for an 8 ohm driver.
Smaller gauge also solves mechanical problems. A driver terminal and a crossover pad have limited space, and 18 AWG fits without levering the terminal or crowding a solder pad. It is also more flexible, which matters when the cable must move with a driver during assembly.
For high power subwoofers and large woofers, 16 AWG or heavier is a reasonable step up. The deciding factor is current and vibration, not length.
Stranded, Not Solid
Use stranded cable internally. Solid core work-hardens and fractures where it flexes near a terminal, and a cabinet vibrates continuously. Fine-strand cable absorbs that movement without breaking.
Insulation and Heat
Crossover resistors and inductors can run warm. Route cable away from hot components and avoid insulation that softens at low temperature. Keep cable off the inside wall of the cabinet where it can buzz against the panel.
Making Joints That Last Decades
A cabinet joint fails for one of two reasons: mechanical stress or oxidation. A good joint addresses both. Solder creates an alloy bond that resists oxidation but needs a clean surface, adequate heat, and no movement while cooling. Crimped connectors create a gas-tight mechanical bond and are faster and more repeatable in production.
Whichever method you use, tin or crimp the wire, not the terminal alone. Excess solder wicked up the strands makes the wire stiff and brittle right where vibration acts.
Soldering Sequence
Strip about a quarter inch, twist the strands, tin them, and let the wire cool before forming it. Heat the terminal and apply solder to the joint rather than to the iron. A shiny, concave fillet indicates a good joint; a dull blob suggests a cold joint that should be redone.
Crimp and Faston Practice
Match the crimp tool to the terminal, pull test every joint, and use insulated terminals where a lead could contact a frame. Re-crimp is not a repair; cut and re-terminate.
Polarity Discipline
Keep the marked conductor on the positive terminal at the crossover and at the driver. A driver wired out of polarity inside a multi-way cabinet damages the crossover region response in a way that is easy to miss during a quick listen.
Service Loops and Mechanical Layout
A service loop is deliberate slack left in the internal wiring so a driver can be unscrewed and set aside without disconnecting or stretching the cable. Without it, every driver removal pulls on a solder joint.
Size the loop to the driver removal path, typically three to four inches of slack. Dress the loop against the cabinet wall, away from the cone and the port, and secure it with a clip or a tie so it cannot migrate into the cone travel.
Check clearance at full excursion. A cable that touches a cone at high output produces a buzz that is hard to localize and often blamed on the driver.
Avoiding Rattles
Any loose cable inside a cabinet is a potential rattle source. Tie it down at intervals, keep it off flat panels, and route it away from port airflow. A small foam pad under a crossover board helps as well.
Sealing the Wire Path
Where internal cable passes through a divider or gasket, seal the opening. An unsealed path between chambers turns a sealed enclosure into a leaky one and costs low frequency output.
Comparison Table
| Driver or position | Typical gauge | Joint method | Note |
|---|---|---|---|
| Tweeter | 18 AWG | Solder or crimp | Short run, low current |
| Midrange | 18 AWG | Solder or crimp | Keep clear of cone travel |
| Woofer | 16 AWG | Solder | Allow a 3 to 4 inch loop |
| Subwoofer driver | 16 to 14 AWG | Solder | Higher continuous current |
| Crossover to terminal cup | 16 AWG | Solder or Faston | Tie down along the wall |
Table: Internal speaker cable choices by driver type
Practical Application Scenarios
- A repair shop recovers a cabinet with a broken tweeter lead caused by a solid core wire that fractured after years of vibration at the terminal.
- A small builder standardizes on 18 AWG stranded internal speaker cable and a four inch service loop so any driver can be swapped in under five minutes.
- A subwoofer assembly moves from 18 AWG to 14 AWG internal cable after repeated high output testing showed warm terminals.
- A technician traces a buzz to a cable resting against a woofer cone and adds two clips to hold the run against the cabinet wall.
Related Products and Further Reading
- internal wiring cable options – Flexible stranded cable in 18 and 16 AWG.
- contact us for build support – Ask about gauge and jacket for cabinet assembly.
- certifications and compliance – Material and jacket compliance documentation.
- 2-conductor speaker wire – The standard construction used inside cabinets.
Frequently Asked Questions
What gauge is internal speaker cable in most cabinets?
Most production cabinets use 18 AWG for tweeters and midranges and 16 AWG for woofers. High power subwoofers often use 16 or 14 AWG.
Can I use solid core wire inside a speaker?
It works electrically but is a poor choice mechanically. Solid core work-hardens and can fracture at a terminal in a vibrating cabinet. Stranded cable is the durable option.
How long should a service loop be?
Three to four inches of slack is typical. The loop should let you remove and set aside a driver without pulling on the joint, while staying clear of the cone and port.
Does internal cable need to be shielded?
No. The signal is high level and the run is short. Shielding adds capacitance and cost with no benefit inside a cabinet.