背部封閉的 HD 25 是針對專業監聽設計的耳筒，對環境噪聲有很高的削弱效果。由於能夠應對極高的聲壓級並有非常結實的結構，此耳筒在高噪音環境中有出眾的表現，例如ENG、擴聲系統、錄音間監聽和音頻設備測試。耳筒聽筒可以旋轉成單耳監聽，是非常適合攝像人員和DJ使用的監聽耳筒。
High sensitivity due to lightweight aluminium voice coils
Capable of handling very high sound pressure levels
Very lightweight and comfortable, even if used for long periods of time
Tough, detachable, single-sided cable
Rotatable capsule for single-ear listening
|Features||HD 25 Light||HD 25||HD 25 Plus|
|Light weight design|
|Single sided cable|
|Rotatable ear cup|
|Extra cable included|
|Extra Ear pads included|
It is a common saying that dynamic microphones just have no maximum SPL.
This saying is not technically exactly correct but for every day use use of dynamic microphones you will not find gain limitations. At SPL levels above 160 dB some mechanical problems might occur (for example the voice coil might crash onto the magnet) but these SPL levels are very hard to find in real world.
Here at Sennheiser we use dynamic microphones for distortion measurements on loudspeakers at very high sound pressure levels. At Sennheiser we have measured the SPL and THD inside a large 2" driver/horn combination with a MD 421. The max SPL this combination was able to produce was 150 dB and the THD level recorded by a MD 421 was below 1% (produced by the driver not by the mic)
So as a conclusion we can state the MD 421 has no maximum SPL limitations for practical use. However if using dynamic microphones at high SPL levels a user should be aware that the very high voltage (up to several volts) delivered by the microphone might cause problems when connected to mic preamps.
If the headphones have sound in only one ear or differing sound levels in each ear or the sound in general is not what you expected then it needs to be determined where the issue lies - with the headphones or with the audio source.
The first thing to do is ensure that you have the audio plug of the headphones connected securely into the audio device. A properly connected cable should not wiggle. If the plug wiggles that could indicate a loose connection. NOTE: This could be a result of the cable not being plugged all the way in or it could be a faulty input or sometimes if the device you are connecting to has a case on it the case will prevent the cable plugging in correctly.
The next thing to do is to check and make sure that there is no debris (ie: no dust or lint) in the headphone jack of the audio source that may be inhibiting connectivity and causing sound issues.
The next thing to do is to check that the connecting jack is clean. If oils from the hands gets builds up on the plug or sweat evaporates on the plug the salts and grime may prevent proper contact from occurring. The connecting jacks can be cleaned using a basic alcohol wipe.The next thing to do is to try the headphones on a different audio source to check that it is not the original audio source (or a setting on the audio source) that is creating the issue. If you connect to an alternate audio source and the issue is not there then you know the headphones are fine and the original audio source is the issue. NOTE: Many modern audio devices have audio limit pre-set at the factory and these limit need to be changed to get the full audio signal out of the device and to the headphones.
Currently Sennheiser offers three (3) models in the HD 25 line
• HD 25 LIGHT
- The HD 25 LIGHT is the essential sound of a HD 25 with a simplified headband.
• HD 25
- The HD 25 is our legendary HD 25 headphone with splayed headband and straight cable.
• HD 25 PLUS
- The HD 25 PLUS is our legendary HD 25 headphone with coiled cable, an additional straight cable, a second set of ear cushions and a protective pouch
These models offer the same sound signature as the legendary HD 25 and sound signature of the headphones is the same across the three models.