Power Requirement Formula
Required power (Watts) = 10^((Target SPL – Speaker Sensitivity + 20×log10(Distance in meters)) / 10)
Where: Target SPL = desired peak volume (typically 95dB for dynamic music), Sensitivity = speaker efficiency at 1W/1m, Distance = listening position to speaker.
Power Reference Table (3m Distance, 95dB Peak)
| Speaker Sensitivity | Required Power (8Ω) | Example Speakers | Recommended TRASAM Amp |
|---|---|---|---|
| 92-95dB | 15-30W | Klipsch horn, JBL L100 | A11PRO (massive headroom) |
| 90-91dB | 30-60W | Focal Aria, Wharfedale Linton | A11PRO (massive headroom) |
| 88-89dB | 60-120W | KEF Q series, B&W 600, Dali | A11PRO (185W) — comfortable |
| 86-87dB | 120-250W | ELAC, Dynaudio Emit, KEF LS50 | A12 PURE (250W), A12PRO (220W) |
| 84-85dB | 200-400W+ | ATC SCM, PMC, Dynaudio Special Forty | AA3PRO (220W), A12 PURE (250W) |
Key Principle: Every 3dB = 2× Power
A 3dB increase in target SPL requires doubling the amplifier power. A speaker with 3dB lower sensitivity also requires double the power for the same volume. This is why the jump from 88dB to 85dB sensitivity is not “just 3dB” — it’s 2× the power requirement.
Signs of Underpowered System
- Sound becomes harsh or compressed above 12 o’clock on the volume dial
- Bass loses definition and “blooms” at higher volumes
- Dynamic peaks in orchestral/rock music sound flattened or congested
- The same speakers produce significantly deeper bass and looser dynamics when driven by a higher-power amplifier (comparative test)
