This is an isolation test I performed while reviewing the Hifiman Audivina. As you can see, the Noires sound leakage is almost nonexistent.
“The purpose of closed headphones is twofold: to isolate the listener from external noise and to prevent the sound produced from leaking into the surrounding environment. I was immediately struck by how little the Audivina's closed cups isolate, so I decided to measure the amount of sound that is emitted to the outside when listening with them. To do this test, I used a white noise generator, flitted from 10,000 Hz with a low-pass filter with Q = 0.5 and measured with a hand-held sound level meter, A-weighting and minimum sensitivity of 30 dB. For reference, I compared the result with my two headphones, the open-cups Ananda and the closed-cups Aeon 2 Noire.
Sound Source: White noise, listening level 80 dBA.
The sound transmitted to the outside, measured at a distance of one metre, is:
- Ananda: 56 dBA
- Audivina: 39.5 dBA
- Aeon 2 Noire: <30 dBA (I do not have the exact value because the sound level meter does not detect sounds below 30 dBA, but a reasonable estimate would be 25 dBA, since at half a metre you get 31 dBA and every time you double the distance, the sound pressure is reduced by 6 dB).”