| Attenuation (passive) |
| Reduction in ambient noise achieved by mechanical means, such as wearing headphones or ear defenders. |
| Connection cable |
| When one speaks about headphones, the emphasis is on such things as sound quality and frequency response. There is rarely any mention of the connection cable. Most Sennheiser headphones are fitted with an OFC (oxygen-free copper) cable. This ensures linear and low-loss transmission in the broad frequency spectrum of the headphones. Many Sennheiser headphones also have detachable cables, which make it very easy to replace them. |
| Connector |
| A standardised single or multi-pole plug for connecting units or accessories. |
| Contact pressure |
| The wearing comfort of a set of headphones is determined not only by its weight but also by the force with which the earpieces are pressed onto the ears. This force is given in newtons (N), whereby 1 N corresponds to the compressive force which a mass of about 100 g exerts on a solid surface. The DIN Standard 45500 Part 10 limits the maximum permissible contact force to 5 N. Values of between 1.3 and 4 N are common, although lower values apply for open headphones. Higher values can be found in the case of closed headphones. Here, a higher contact pressure is required in order to achieve sufficient sealing, which is important for the reproduction of low frequencies. |
| Ear coupling |
| A distinction is made between headphones which are worn on the external ear (supra-aural) and those which surround the ear (circumaural). Open headphones have foam ear pads that rest on the ears or ring pads that surround the ears. Closed headphones, on the other hand, nearly always have circumaural ear pads. |
| Frequency response (headphones) |
| The frequency response of a pair of headphones is given within limits defined by the manufacturer. |
| Nominal impedance |
| See impedance. |
| Operating temperature |
| Gives the range of temperatures at which a unit can be operated without damage. |
| Operating voltage (stand alone) |
| Voltage type and level required for powering a unit. |
| Output voltage |
| The (signal) voltage which a unit supplies at its output. |
| Sound pressure level (SPL) |
| Due to the impractical numerical values, the sound pressure is usually given as the logarithmic value of the sound pressure level according to the equation: dB SPL = 20 x log (po / 0.00002 Pa). The abbreviation SPL (sound pressure level) is added in order to make a clear distinction from other uses of dB. The reference sound pressure, which is at the same time the threshold of hearing, is then 0 dB SPL. The threshold of pain is 140 dB SPL. A difference in the sound pressure level of 1 dB is just about perceptible, while a doubling of the sound pressure corresponds to 6 dB and a doubling of the volume corresponds to a rise of 10 dB.
|
| Storage temperature |
| Gives the range of temperatures at which a unit can be stored without damage. |
| Transducer principle |
| Two transducer principles have become established for the conversion of electric energy into mechanical energy: electrodynamic and electrostatic transducers, whereby the latter is only to be found in audiophile systems, due to their relatively high manufacturing costs. Electrodynamic transducers basically consist of a ring-shaped permanent magnet and an oscillation coil, which is fixed to the receiver diaphragm. When an audio-frequency alternating current is passed through the oscillation coil, it is caused to vibrate in accordance with the audio-frequency alternating current, thus causing the diaphragm to vibrate in the same way. |
| Transducer principle (microphone) |
| Operating principle of a microphone. The transducer may be dynamic, piezoelectric or condenser. |
