The Philips SHP9600 is 32Ω at 102.0 dB (no reference unit printed); the Sennheiser HD 800S is 300Ω at 96.8 dB/mW. This page is only about what they ask of an amplifier — not how they sound, which no specification on either sheet can tell you.
The Sennheiser HD 800S needs 5.2 dB more than the Philips SHP9600 to reach the same loudness — 2.1 mW against 0.63 mW.
| Specification | Philips SHP9600 | Sennheiser HD 800S |
|---|---|---|
| Impedance | 32 Ω | 300 Ω |
| Sensitivity | 102.0 dB | 96.8 dB/mW |
| Sensitivity (voltage) | 116.9 dB/V | 102.0 dB/V |
| Power for 100 dB | 0.63 mW | 2.1 mW |
| Voltage for 100 dB | 0.14 V | 0.79 V |
| Current for 100 dB | 4.4 mA | 2.6 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 4.00 Ω | 37.50 Ω |
| Sources that reach 100 dB out of 280 | 280 | 277 |
One caution before reading the rows. Philips SHP9600 printed a decibel figure with no reference unit, so this page reads it as per milliwatt. If it is really per volt, that model needs far more than the table says. Why the two readings differ by so much.
3 of the 280 sources have the power for the Philips SHP9600 but not for the Sennheiser HD 800S — Apple USB-C dongle (EU), Steinberg UR22C, Sony NW-A306.
20 sources are low enough in output impedance for the Sennheiser HD 800S under the one-eighth rule but not for the Philips SHP9600 (Zoom AMS-22, Arturia MiniFuse 2, Arturia MiniFuse 1, 17 more).
277 of the 280 sources here reach 100 dB on both. That count is about power only — the output-impedance and hiss lines above are separate questions, and a source can pass this one and fail those.
Each model has a page of its own with the full source list, the hiss estimate and the provenance of every figure above: Philips SHP9600 and Sennheiser HD 800S. Each figure on this page is labelled on those pages with where it came from, including the ones Philips and Sennheiser never published — what Philips publishes and what Sennheiser publishes, both counted.