Quick answer: Cheap speaker cable is a bargain only when the conductor is copper and thick enough for the run. Copper clad aluminum costs less because aluminum carries less current for the same thickness, so an identical gauge measures higher resistance and turns more amplifier power into heat. Check the printed gauge, scrape a cut strand, compare loop resistance against speaker impedance, and stop saving on long runs or four ohm loads.
Two reels sit side by side, both printed 16 gauge, and one costs a third of the other. The cheaper reel feels lighter, its strands nick against a thumbnail, and the print rubs off in a toolbox. Weight is the whole story: a lighter conductor at the same nominal size means a different metal inside, and the difference shows up as level loss at the terminals.
Why a low price changes the metal, not the label
Price per foot tracks the copper market, so a reel that undercuts everything around it has changed something inside. Copper clad aluminum is the usual answer: an aluminum core with a thin copper skin, drawn to the same outside diameter as a copper strand. The gauge on the jacket stays the same and the difference stays invisible until you cut an end.
Three checks you can run in the shop
Scrape the cut end
Cut one strand and scrape it along a hard surface with a knife blade held flat. Copper stays copper all the way through. A clad strand shows a bright silver core under the skin, and that core gouges easily because aluminum is soft. Repeat on two strands from different loops of the reel.
Measure loop resistance
Measure a known length out and back with a meter that resolves tenths of an ohm, then divide by the total length. Short the probes first and subtract that lead reading. A clad reel of the same gauge reads noticeably higher, and the gap widens as the conductor thins.
The loss penalty of an undersized conductor
Every ohm in the cable sits in series with the voice coil, so amplifier voltage divides between the two. A loop resistance that reaches a fifth of the speaker impedance takes a visible share of the power before the driver sees it, and that share leaves the jacket as heat. The result is level loss that grows with distance.
Run length sets the size
Doubling the length doubles the resistance, so a size that works at fifteen feet is marginal at sixty. Runs to a four ohm speaker feel the penalty twice as hard as runs to eight ohms, which is why patio and surround channels go quiet first.
Heat at the terminals
Current density rises as the conductor shrinks. At high levels a thin clad conductor warms at the plug, and repeated heating loosens the screw terminal, adding contact resistance on top of conductor resistance.
| Check | Bare copper | Clad | Meaning |
|---|
| Scraped strand | Copper color through | Silver core | Different metal, same gauge |
| Weight per foot | Heavier | Lighter | A scale beats a label |
| Ohms per foot | Lower | Higher | More signal lost as heat |
| Bend fatigue | Flexes and recovers | Core cracks | Intermittent channel later |
What clad cable does at the terminals
Aluminum oxidizes faster than copper, and its oxide is an insulator. A clad conductor stripped and left bare builds a resistive film where the strand meets the terminal, so the joint degrades long after the install looked finished. Crimped or sealed terminations slow that down. Bare wire in a spring clip outdoors does not.
Where a low price is still safe
Saving on short runs to eight ohm speakers is reasonable, because the resistance is tiny against the load and the amplifier has margin. Stop saving past roughly thirty feet, on any four ohm load, and on cable that disappears into a wall you cannot open again. Cheap is a length and load decision before it is a brand decision.
Practical scenarios
- Workshop bench pair: Two three foot runs to bookshelf speakers will not care about conductor metal, so the cheapest reel in the drawer is fine.
- Whole house audio: Runs of forty to eighty feet to ceiling speakers pair badly with clad 18 gauge, because the resistance share lands where level loss is obvious room to room.
- Patio speakers: Moisture plus an aluminum core is short lived, since oxide film forms fast on any strand left bare at the terminal.
- Rented rehearsal room: Long temporary runs get coiled weekly, and a clad core cracks at the bend points before the jacket shows damage.
FAQ
Can I hear clad cable versus copper?
On a short run to an eight ohm speaker, usually not. On a long run, a four ohm load, or a high level, it appears as a small level loss and a warm plug, not an obvious defect.
Does a thicker clad cable fix resistance?
Going up two sizes brings clad close to the copper value at the original size, but the cable gets stiff, heavy and awkward around corners.
Is the printed gauge reliable?
Treat it as a claim. The number describes the outside diameter of the strand bundle, which copper and clad cable both meet while carrying different amounts of metal.
Next step
If the reel in your hand fails the scrape check, replace it with a known copper construction and size up for long runs; the 12 gauge speaker cable page covers the heavy end, the 14 AWG speaker cable page covers the middle, and the 12AWG OFC speaker wire page explains stranding in plain terms.
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