Has Passive Noise Reduction
Passive Noise Cancellation uses well-designed ear cups to seal out environment noise. This is used for both in-ear earphones and over-ear headphones where the headphone itself will keep surrounding noise out.
The Sennheiser HD 660S2 sits tightly in place, creating an acoustic seal that reduces background noise and prevents your music from leaking out.
Lowest Frequency
Low-frequency response measures if and how well an audio device reproduces low audible frequencies and if it makes any changes to the signal while at it. Sennheiser HD 660S2's lowest frequency is at 8Hz, the lower the low-frequency response, the stronger and juicier the bass.
Highest Frequency
Sennheiser HD 660S2
41500Hz
High frequency response measures if and how well a particular audio component reproduces high audible frequencies and if it makes any changes to the signal on the way through. Sennheiser HD 660S2's highest frequency is at 41500Hz, the higher the high-frequency response, the clearer and crispier the treble.
Sound Pressure Level
Sennheiser HD 660S2
104dB/mW
Sound pressure is the average variation in atmospheric pressure caused by the sound, the sound level .i.e how loud something is can be perceived differently by different people so we need to have a way of getting an objective measurement of sound level expressed in numerical terms.
The sound pressure level, SPL, is the pressure level of a sound, measured in decibels, dB, Sennheiser HD 660S2's measurement is 104dB/mW. Devices with a higher sound pressure level are generally louder when supplied with any given audio source.
Driver Unit Size
The driver unit is basically a mini speaker that produces sound in the device, its size dictates the loudness of the headphone. Sennheiser HD 660S2 driver unit is 38mm in diameter, bigger drivers are more powerful and can produce better bass.
Impedance
Sennheiser HD 660S2
300Ohms
Defined as the device's resistance to the electromagnetic current, when electricity flows through a wire, it experiences electrical resistance that counters the flow of current. The resistance of a wire is measured in ohms. Sennheiser HD 660S2's impedance is 300Ohms, the lower the impedance, the easier it is to get higher volume and requires less power.
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