audiometers, closed dynamic headphones
General Description
Optimized for use with audiometers for evaluating patients with hearing concerns. The HDA 280 is specially designed for hearing tests for frequencies up to 12 kHz.
Features
- Excellent reproduction of readings
- Suitable for testing frequencies up to 12kHz
- Soft, replaceable ear pads
- Padded headband for increased comfort
- Single-sided cable
- Design approved by the PTB (German organization for type approvals, a national standards organization similar to the British Standards Institute or the American National Bureau of Standards)
Delivery Includes
- HDA 280 audiometer headphones
- Unterminated cable (approx. 3m)
- Spec sheet (German/English)
- Warranty card
audiometers, closed dynamic headphones
Technical Data
| Characteristic SPL |
117 dB |
| Connection cable |
Approx. 10 ft. (3 m) long, open cable end |
| Contact pressure |
5 N ± 0.5 N |
| Ear coupling |
On-the-ear |
| Frequency response (headphones) |
20 - 20,000 Hz |
| Load rating |
500 mW (EN 60268-7) |
| Nominal impedance |
37 Ω |
| Transducer principle |
Dynamic, closed |
| Weight incl. cable |
11.6 oz. (330 g) |
audiometers, closed dynamic headphones
Recommended Accessories
| Part/Accessory |
Article No. |
audiometers, closed dynamic headphones
Variants
Glossary
| 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. |
| 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. |
| Load rating |
| The load rating is the amount of electric power which - according to the manufacturer´s specifications - can be continuously supplied to a set of headphones over a period of time without causing damage. According to DIN 45500 Part 10, the load rating must be at least 100 mW. Testing is carried out using a special noise signal which is supplied to the headphones over a period of 100 hours. |
| Nominal impedance |
| See impedance. |
| 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. |
