In the copper vs silver debate, the measurable gap is small: silver conducts only about 5% better than copper. At the same thickness, the difference in resistance is tiny. What really separates copper, silver, silver-plated copper and gold-silver cables is conductor size, construction, ageing, handling and price. The sound people describe for each material comes from the whole design, not the metal alone.
This guide is for anyone choosing an IEM or headphone cable and wondering whether copper vs silver should decide it. You'll learn what the physics says, what terms like OCC, 7N and Litz mean, and where each Null Audio cable sits. Cable makers, us included, talk about materials a lot, so we separate what's measurable from what's a matter of taste.
Key takeaways
- Silver's resistivity at 20 °C is 1.59 × 10⁻⁸ Ω·m and copper's is 1.68 × 10⁻⁸ Ω·m, so silver is only about 5% lower.
- Conductor thickness matters more than the metal: a thick copper cable can have lower resistance than a thin silver one.
- In silver-plated copper, the copper core carries almost all of the audio signal; the silver layer mainly protects the surface.
- Silver tarnishes to silver sulfide and copper turns green, so jacket quality and care matter for both.
- Null Audio makes copper (Arete, Tiburon), silver (Thera), hybrid (Lune, Hakone) and gold-silver (Aoraki, Moebius) cables, all built to order in Singapore.
Copper vs silver and other materials at a glance
A conductor is the metal inside the cable that carries the signal. Most IEM and headphone cables use one of six families. The table compares them on the properties you can actually check.
| Material | Resistivity at 20 °C | Strengths | Trade-offs | Null Audio cables |
|---|---|---|---|---|
| Copper (OCC / UPOCC, 5N–7N) | about 1.68 × 10⁻⁸ Ω·m | Very good conductor at a sensible price; flexible; easy to make thick | Oxidises (turns dark or green) if moisture gets in | Brevity Pro, Arete, Epsilon, Tiburon, Ethos Ultra (copper core) |
| Silver (UPOCC, 7N) | about 1.59 × 10⁻⁸ Ω·m | The best conductor of any metal | Expensive; tarnishes; usually stiffer at the same gauge | Thera |
| Silver-plated copper (SPC) | close to copper (the core carries most of the signal) | Copper's price and flexibility with a silver surface that resists corrosion better | Plating can wear at bends over many years | Ethos MKIII |
| Silver/copper hybrids and alloys | between copper and silver | Lets the designer balance the two | Price | Lune (silver/copper alloy), Hakone (silver + copper) |
| Gold-silver alloys and gold-plated silver | higher than pure silver (gold alloys conduct less well) | Gold resists corrosion; a premium material choice | Highest cost | Aoraki, Moebius |
| Graphene-coated copper | Istana is rated above 110% IACS conductivity | Coating resists oxidation and corrosion | Price | Istana |
Prices follow the materials. Brevity Pro starts at USD 49 and Arete at USD 109. Thera, in pure silver, starts at USD 399.
Is silver really a better conductor than copper?
Yes, but only slightly. Resistivity is the property that tells you how strongly a metal resists current. According to the HyperPhysics resistivity table, silver measures 1.59 × 10⁻⁸ Ω·m at 20 °C and copper 1.68 × 10⁻⁸ Ω·m. That makes silver about 5% better.
In a cable, that 5% applies to a resistance that is already small. A typical IEM cable has a resistance of under about an ohm. Five per cent of that is a few hundredths of an ohm. For comparison, the engineer Rod Elliott measured a normal cable at 0.2 ohms against a deliberately resistive one at 10.9 ohms (Elliott Sound Products). Copper vs silver alone moves you nowhere near that range.
So why do listeners describe silver cables as brighter or more detailed? We think the answer is the whole design: conductor size, geometry, insulation and the plugs. We describe Thera as accurate with strong vocal definition, and Tiburon as warm with full-bodied vocals. Those are our descriptions of complete cables, not properties of the metals on their own.
Why does thickness matter more than the metal?
Resistance depends on the material and the cross-section. Double the cross-section and you halve the resistance. A thick copper cable will therefore have lower resistance than a thin silver one.
That's why our current Symphonym generation (Tiburon, Thera and Hakone MKIII) uses conductors 1.5 times larger in cross-section than the previous generation. It's also why we quote gauge and strand counts. Arete MKV uses 100 strands per cable at 24 AWG. Istana uses 70 conductor strands at 24 AWG. Epsilon has 126 strands per wire and 504 strands per cable.
Low resistance matters most with low-impedance, multi-driver IEMs. The source's output impedance and the cable's resistance form a voltage divider with the earphone. A multi-driver IEM's impedance varies with frequency, so extra series resistance can shift its frequency response. A common rule of thumb is to keep output impedance at or below 1/8 of the headphone's impedance (Headphones.com). We explain this in more detail in Do IEM upgrade cables make a difference?
What is silver-plated copper?
Silver-plated copper (SPC) is a copper conductor with a thin layer of silver on its surface. It is a popular middle ground because it keeps copper's price and flexibility.
A common claim is that the silver layer carries the treble. The physics doesn't support that at audio frequencies. Skin depth is the depth at which most AC current flows in a conductor. In copper it is about 8.4 mm at 60 Hz and about 0.27 mm at 60 kHz. Both figures are far larger than a fine cable strand, so the current uses the whole copper strand. The plating carries a negligible share.
What the silver layer does well is protect the surface. Our Ethos MKIII uses UPOCC silver-plated copper. Ethos Ultra pairs a 5N single-crystal copper signal conductor with a silver-plated copper shield around a Kevlar core.
What OCC, UPOCC, 7N, cryo and Litz mean
Cable listings are full of shorthand. Here is what each term means.
- OCC / UPOCC (Ohno Continuous Casting): a casting process that produces very long single crystals of metal, so a strand has few grain boundaries along its length.
- 5N, 6N, 7N: purity, counted in nines. 7N means 99.99999% pure. Brevity Pro uses 5N copper; Tiburon uses 7N copper and Thera 7N silver.
- Cryogenic treatment: the finished conductor is slowly cooled to very low temperatures and warmed again, a treatment intended to relieve internal stress in the metal.
- Litz: individually insulated strands bundled in a pattern, so the strands don't touch each other along the run. Lune uses a custom Litz build with 53 strands per wire and 212 strands per cable.
These are construction choices, and they affect how a cable handles and ages as well as how it measures. We list them because they describe what you're buying, not because any single one guarantees a sound.
How copper vs silver cables age
Both metals react with air over time, in different ways. Silver tarnish is mainly silver sulfide, formed by hydrogen sulfide in the air (Canadian Conservation Institute). Copper develops a green patina, usually basic copper carbonate, or chlorides near the sea (Wikipedia: Patina).
In a cable, the jacket is the main defence. Discolouration usually means moisture or air has reached the conductor. That matters in a humid climate like Singapore's. Coatings help too: Istana's graphene coating is designed to resist oxidation and corrosion.
Which material should you choose?
Start with how you'll use the cable, then your budget, then the sound you like.
Everyday, on the go, on a budget
Copper or SPC is light, flexible and durable. Consider Brevity Pro (four 26 AWG 5N copper wires), Ethos Ultra, Arete or Epsilon.
A balance of both
Lune has been a Null Audio best-seller for 15 years running. It uses a silver/copper fusion alloy with thick silver plating. Hakone combines 7N silver and 7N copper.
Thick pure copper or pure silver
Choose Tiburon for 7N copper or Thera for 7N silver.
Flagship
Aoraki uses a 28 + 28 + 8 strand gold-silver geometry. Istana is graphene-coated copper. Moebius has an 8.8% gold/silver fusion core.
Material is only one part of the choice. The connector and plug must match your gear. If you're unsure, read our guides to IEM cable connectors and 3.5 mm, 2.5 mm and 4.4 mm balanced plugs.
Find the right cable for your IEM
The best way to settle copper vs silver for yourself is to listen. Visit our Singapore studio to compare cables on your own IEMs. Every cable is built to order with the connector and plug you choose.
Look up your model in Find My Cable, which covers over 400 IEMs, or browse all IEM and headphone cables. You can also tell us your IEM, player and the sound you like, and we'll suggest a match.
Frequently asked questions
Do silver IEM cables sound brighter than copper?
Silver conducts only about 5% better than copper, so the metal alone changes resistance very little. Differences people hear usually come from the whole design, including conductor size, geometry and plugs. We describe our pure-silver Thera as accurate with strong vocal definition, but that describes the complete cable, not silver itself.
Is silver-plated copper as good as pure silver?
Silver-plated copper is a copper conductor with a thin silver surface. At audio frequencies the current flows through the whole copper strand, so it behaves electrically much like copper. The silver layer mainly protects the surface, and the cable keeps copper's lower price and flexibility.
Why is my silver cable turning black?
Silver tarnish is mainly silver sulfide, which forms when silver reacts with hydrogen sulfide in the air. Discolouration under the jacket usually means air or moisture has reached the conductor. Store the cable dry and loosely coiled to slow it down.
Why do copper cables turn green?
Copper slowly forms a green patina, usually basic copper carbonate, or copper chlorides near the sea. In a cable this normally means moisture has got past the jacket. Corrosion can't be repaired under Null Audio's repair service, so keeping the cable dry matters.
What does 7N mean on a cable?
7N means the metal is 99.99999% pure, counted in nines. Null Audio's Tiburon uses 7N copper and Thera uses 7N silver. Purity is one construction choice among several, alongside conductor size, casting method and geometry.
Is a thicker cable better than a silver cable?
For resistance, thickness usually matters more than the metal, because doubling the cross-section halves the resistance. A thick copper cable can measure lower resistance than a thin silver one. Low resistance matters most with low-impedance, multi-driver IEMs.
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