IEM Impedance & Sensitivity Explained: What GK AudioLab's Specs Tell You
A practical guide to understanding IEM impedance and sensitivity specs — and how GK AudioLab's 32Ω / 110–115dB/mW lineup affects source pairing, volume, and sound quality.
Two Numbers That Define Drivability
Every IEM spec sheet lists impedance (in ohms, Ω) and sensitivity (in dB/mW or dB/Vrms). These two numbers, taken together, determine how loud your IEM will play from a given source and whether the source's output impedance will affect the frequency response. Understanding them makes you a smarter buyer.
Impedance: Electrical Resistance to Current Flow
Impedance is the total opposition to AC current flow in a transducer, including resistive (DC resistance) and reactive (inductive/capacitive) components. At 1kHz, a 32Ω IEM presents a moderately low load — easy for any source to drive.
All GK AudioLab IEMs are rated at 32Ω. This is a deliberate choice:
- Low enough that smartphones and laptops can drive them without distortion
- High enough to minimize background noise (hiss) from high-output-impedance sources like cheap amplifiers
- Compatible with the 1/8 rule: sources with output impedance <4Ω will not cause frequency response shift on GK IEMs
Sensitivity: Loudness Per Unit of Power
Sensitivity (dB/mW) tells you how much sound pressure level (SPL) 1 milliwatt of power produces at 1kHz. Higher sensitivity = louder for the same electrical input.
GK AudioLab's range:
| Product | Sensitivity | Character |
|---|---|---|
| X1, G2 | 110 dB/mW | Easy to drive; max volume from phone at 60–70% |
| AK8, G1 PRO, G3, G6 | 112 dB/mW | 2dB louder per mW than X1; efficient |
| AK8 Pro, G4, G5 | 113–114 dB/mW | Very efficient; caution with high-gain amplifiers |
| KUNTEN | 115 dB/mW | Flagship; very sensitive — reveals source hiss on noisy outputs |
The Sensitivity-Noise Trade-Off
High sensitivity is a double-edged sword. The KUNTEN's 115dB/mW rating means it converts every microwatt of electrical noise in the signal chain into audible hiss. Pair it with a noisy source and you'll hear the noise floor clearly in quiet passages.
GK AudioLab's recommendation (and ours): pair 110–112dB/mW IEMs with smartphones and laptop headphone jacks without concern. For the AK8 Pro (114dB) and KUNTEN (115dB), a clean source like an Apple USB-C dongle or a dedicated DAC/amp with a rated SNR >110dB will let the IEM perform at its peak.
Output Impedance: The Hidden Source Spec
Your source's output impedance can alter an IEM's frequency response through electrical damping interaction. The "1/8 rule" states that for flat frequency response, the source's output impedance should be no more than 1/8 of the IEM's impedance:
Source output impedance ≤ IEM impedance / 8
For GK's 32Ω IEMs: source output impedance should be ≤4Ω. Common sources:
- iPhone Lightning/USB-C dongle: ~1Ω ✓
- Samsung Galaxy audio output: ~2Ω ✓
- Apple MacBook 3.5mm: ~4Ω ✓
- Old-generation portable amplifiers: may be 10–30Ω ✗
If your amplifier has high output impedance, you may notice bass-heavy or treble-altered response on GK IEMs. The solution is a modern DAC/amp with specified low output impedance.
Summary
GK AudioLab's standardized 32Ω / 110–115dB/mW spec across the lineup reflects smart engineering: the IEMs are accessible to casual listeners using smartphones while remaining technically compatible with high-end DAC/amp pairings for enthusiasts. The KUNTEN is the only model that rewards a quality source investment — which is appropriate given its $89 flagship price.