The short answer: impedance tells you part of the electrical load, while sensitivity tells you how much acoustic output the headphone produces for a stated input. Compare both with the source's output power, voltage, gain, output impedance and noise before deciding that an amplifier is required.
Sennheiser explains that high-impedance headphones can be too quiet for some mobile devices and that model-specific source capability matters. Shure amplifier specifications likewise publish power at different loads, showing why one headline number is not enough.
Impedance is not drive difficulty by itself
Higher impedance often requires more voltage for a given power, while lower impedance can demand more current. Sensitivity determines how that electrical input becomes sound. A low-impedance, low-sensitivity headphone may still be demanding.
Compare sensitivity units carefully. dB per milliwatt and dB per volt are not directly interchangeable without calculation and impedance information.
Check what the source actually publishes
Look for output power into relevant impedances, maximum voltage, gain options and output impedance. A phone may drive one headphone cleanly but leave little headroom with another. A desktop amplifier may be too noisy for a highly sensitive in-ear monitor.
Do not infer performance from the connector size. A 6.35 mm socket is not automatically more powerful than 3.5 mm, and balanced headphone connectors need exact compatible wiring.
Identify the real symptom
| Symptom | Possible issue | Useful check |
|---|---|---|
| Not loud enough | Insufficient voltage or gain | Source output into the actual load |
| Distorts on peaks | Insufficient clean headroom | Lower level and compare another output |
| Audible hiss | Source noise with sensitive earphones | Low-gain or lower-noise output |
| Tonal balance changes | Output impedance interaction | Manufacturer compatibility guidance |
Decide whether an amplifier solves the problem
A dedicated amplifier is useful when the current source lacks clean level, headroom, a suitable output impedance or practical volume control. It is not required merely because the headphone is expensive.
If the existing source reaches normal level cleanly with usable control and low noise, another amplifier may add features rather than fix a drive problem. Compare at matched loudness.
Connect and test safely
- Set the source or amplifier to low gain and minimum safe volume.
- Connect the correct headphone plug or approved adapter.
- Play a familiar track and raise level gradually.
- Check quiet passages for hiss and peaks for strain.
- Try the normal listening duration for comfort and heat.
- Reduce level before unplugging or switching outputs.
Practical checklist
- Impedance and sensitivity units are both known.
- Source output is published for a relevant load.
- Gain and noise suit the headphone or IEM.
- Connector wiring is compatible.
- Normal level is reached without strain.
- Volume control has a useful adjustment range.
- Comparisons use matched loudness.
Troubleshooting guide
| What you notice | Check first | Next step |
|---|---|---|
| High-impedance headphone is too quiet | Source voltage and gain | Test a compatible amplifier |
| Sensitive IEM hisses | Output noise and gain | Use a lower-noise, low-gain output |
| Bass changes between sources | Output impedance interaction | Review source and headphone specifications |
| Balanced adapter causes channel problems | Incompatible wiring | Stop and use the manufacturer's approved cable |
Continue your Miu Audio research
Miu Audio's broader listening guidance can help structure a headphone audition, but no specific unconfirmed headphone or amplifier is recommended here. Verify current showroom availability first.
- Explore the confirmed Miu Audio LS3/5a
- Browse Audiophile Hi-Fi guides
- Plan a Springvale showroom visit
Frequently asked questions
Do high-impedance headphones always need an amp?
No. They need a source with sufficient clean voltage and gain. Some devices can provide that; others cannot, so compare exact specifications.
Are low-impedance headphones easy to drive?
Not automatically. Sensitivity and current demand also matter, and highly sensitive models may reveal source noise.
What headphone sensitivity is good?
Sensitivity is not a quality score. It helps predict output for a stated input and must be read with impedance and the measurement unit.
Will a headphone amp improve sound quality?
It can solve inadequate level, headroom, noise or output-impedance problems. If the current source already performs cleanly, gains may be functional rather than dramatic.
Sources
- What is impedance and why is it important when using my headphones?, Sennheiser Hearing, accessed 30 July 2026.
- SHA900 User Guide, Shure, accessed 30 July 2026.
- Miu Audio Showroom, Miu Audio, accessed 30 July 2026.
Headphone output and connector requirements vary by model. Start at low level, use approved cables and compare exact source specifications rather than relying on impedance alone.