Do IEM Upgrade Cables Make a Difference? What We Can Measure

Yes, IEM upgrade cables can make a difference, but mostly in specific, explainable ways. They can lower resistance, which matters with low-impedance multi-driver IEMs. They can improve comfort, cut cable noise, last longer and give you the right plug, including balanced. Claims about the “sound” of a particular metal are a matter of listening and taste.

We've built cables by hand in Singapore since 2008, so we have an obvious interest in this question. This guide is for IEM owners deciding whether IEM upgrade cables are worth the money. Here is what we can explain and measure, and where it stops.

What can IEM upgrade cables change?

An upgrade cable is a replacement cable for a detachable earphone, chosen to improve on the one in the box. It does not change the drivers or the tuning inside the shell. It can only change what happens between your player and the earpiece.

That still leaves five practical areas. The table sums them up before we go through each one.

Does cable resistance change the sound?

It can, in one specific case. A cable adds a small resistance between your player and your earphones. Together with your player's output impedance, it forms a voltage divider with the earphone's own impedance.

• With a single dynamic driver, impedance is fairly flat across frequencies, so a small extra resistance just lowers the volume very slightly.
• With a multi-driver IEM, especially balanced-armature designs with crossovers, impedance can swing widely with frequency and can be very low. Extra series resistance then changes the level of some frequencies more than others. The tuning shifts away from what the designer intended.

A common rule of thumb is to keep the source's output impedance under about one-eighth of the earphone's impedance (explained here by Headphones.com). Cable resistance adds to that output impedance.

How big is the effect?

A typical cable adds well under about an ohm, so with most earphones the effect is small. To show the scale, Rod Elliott compared a deliberately high-resistance cable of 10.9 Ω with a normal one of 0.2 Ω (Elliott Sound Products). Thin cables and very low-impedance IEMs make the effect bigger.

This is the one sound-related cable effect that's straightforward physics. It's why our current generation of Tiburon, Thera and Hakone uses conductors 1.5 times larger in cross-section than before. Epsilon, with 126 strands per wire and 504 per cable, is tuned by engineers at our sister brand AAW for sensitive IEMs.

Comfort, handling and cable noise

Microphonics is the noise you hear when a cable rubs against clothing or skin and the vibration travels up into your ears (Sennheiser). It depends on the cable's jacket, stiffness and ear hooks.

A soft cable that holds its shape around the ear without springing back is noticeably quieter and more comfortable. That matters most when you're walking or on stage. For many people this is the most obvious improvement over a stock cable.

Memory effect is the tendency of a cable to keep kinks and coils. Brevity Pro, from USD 49, uses four 26 AWG 5N copper wires in soft TPE with little memory effect.

The right plug and a secure fit

Choosing the player end

A replacement cable lets you choose the player end: 4.4 mm or 2.5 mm balanced, 3.5 mm, XLR for desktop amplifiers, or a USB-C or Lightning DAC plug for a phone. Many players deliver considerably more power from their balanced output. FiiO, for example, rates its KA13 dongle at 170 mW from 3.5 mm and 550 mW from 4.4 mm into 32 Ω. That's a real, measurable change, though it comes from the player; the cable is what lets you use it. See 3.5 mm, 2.5 mm or 4.4 mm balanced?

Matching the connector

A cable that doesn't seat fully in the socket can cause crackling, intermittent sound or a loose earpiece. Recessed 0.78 mm 2-pin sockets, qdc-style connectors and brand-specific sockets such as the Sennheiser IE 300/600/900 or Etymotic ER4SR need the correct plug. See which IEM cable connector you have, or look your model up in Find My Cable.

Durability and repairability

Stock cables are often the first part of an IEM to fail: at the plugs, at the Y-split, or at the ear hooks. Better strain relief and stronger construction help. Ethos Ultra, for example, is built around a Kevlar core for strength.

A repair service makes a cable a long-term part of your setup. Null Audio cables have a 1-year warranty against defects in materials and workmanship. Products bought within 3 years qualify for flat-rate repair from USD 30, usually done within 4 weeks. Repairs can fix lost signal and damaged connectors, but not a cut cable or a damaged jacket.

What about materials and “sound signatures”?

Copper and silver differ in resistivity by only about 5% at the same thickness. At 20 °C, silver is 1.59×10⁻⁸ Ω·m and copper is 1.68×10⁻⁸ Ω·m (HyperPhysics). On paper, the metal alone makes a small difference.

Some terms are worth knowing. 7N is a purity grade of 99.99999%. OCC is Ohno Continuous Casting, which produces very long single crystals. Litz is a build where strands are individually insulated. Silver-plated copper is a copper conductor with a silver layer; at audio frequencies, current flows through the whole copper strand, so the plating carries a negligible share.

Many listeners, including us, do hear cables differently, and we tune and describe our cables by ear. For example, we describe Arete, with 100 strands at 24 AWG, as dynamic with deep bass. Those descriptions are our listening impressions, not measurements, and we'd encourage you to treat them that way.

Are IEM upgrade cables worth it for you?

An upgrade is worth it if your stock cable is noisy, stiff, failing or has the wrong plug. It is also worth it if you own a low-impedance multi-driver IEM and your current cable is thin. If your cable already fits, sits quietly and works, the gains are smaller and more personal.

The fairest test is your own ears with your own IEMs. Visit our studio at 76 Playfair Road, Singapore, to compare, or start with a cable that gets the practical points right. Compare materials in all IEM and headphone cables, or tell us your IEM and player and we'll suggest a cable.

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