Can I use my RF wireless headphones wherever I am?

You can use your Sennheiser RF wireless headphones nearly everywhere (but they aren't meant for underwater use, and we haven't done a space test yet, either!) but please consider that you may not be allowed to use them everywhere. Different countries have different RF approval requirements. Please check your instructions for use or contact our local partner. Some areas, such as hospitals or airplanes, may also have special restrictions.



Why do headphones sound different from speakers?

Put your head directly between two loudspeakers and you will realize that they sound different than you are used to. Our ears are formed by evolution to perceive information from our surroundings. Our brain is trained to localize these sounds. For the localization, the brain uses so-called spectral differences and time delays. Spectral differences are caused by the contour of the listener's head: sounds will sound different depending on which direction they come from. Also, the brain will notice a difference in time when a signal reaches the left and right ear. It uses this delay to localize the sound source.
Wearing headphones prevent perceiving the majority of these differences as the sound source is located close and directly opposite to the ear. Our trained brain will locate the sound source more or less in our head.
But cutting out spatial information can be an advantage. Only very few people can afford a perfect listening room for loudspeakers. And without that our ears obtain many sound reflections from furniture, walls, etc. which distort the pure sound of the speaker. Did you know that a speaker system costs approx. 10 times more than headphones with the same audio quality?



Can headphones be dangerous?

Headphones are not dangerous but incorrect usage may cause problems. Listening too long to high volumes can cause hearing damage ? from any source. The longer you listen the lower the volume should be. An official recommendation is max. 85 dB SPL if you listen longer than 8 hours. If you can't measure the volume please use this rule of thumb: While listening to (open) headphones, people should still be able to talk to you without shouting. Please also consider that cutting out surrounding sound may be dangerous in some situations such as in traffic (bicycling, etc.) or while taking care of a baby.

Humans always are suspicious towards everything they can't perceive. Wireless transmission has been analyzed intensively. The frequencies and the output power of Sennheiser wireless products are within limits where no dangerous effects on humans are known (even for people wearing hearing aids or cardiac pacemakers). We do intensive research before launching new technologies and work together with consumer protection associations, universities and government project groups.



Sennheiser has so many different headphones, how will I know which one is the right one for me?

In addition to the recommendations of Sennheiser and the technical product information, only your ears can give you the right answer.
Everybody perceives sound differently due to ear shape, cultural influences, habits, etc. Whenever you think about buying a good headphone set, make sure that you listen to it before you buy it. Use music you know very well, but make sure it is music that contains different instruments and voices with different volume levels. Sometimes audio magazines have good test CDs (skip the tracks specifically for loudspeakers). Some headphones include processors to change the original signal deliberately to obtain a surround sound impression (like the RS 65). Try them with and without the encoding to get a proper impression. But please remember that the algorithms are made for music and vocals, so pure test signals may sound strange.
Humans do not have an acoustical memory. It is only through experience and a few "tricks" that sound engineers ( or other professionals) can remember how a headphone sounds. The easiest thing for you is to compare the new headphones with old ones or speaker sound.



What can I connect my headphones to?

All Sennheiser consumer headphones have standard stereo jack plugs in 3.5 or 6.3mm (1/4"). You can plug them into any headphone jack of that size (portable stereos, receivers, integrated amplifiers of CD players, TVs, even into your PC soundcard). But you will notice different sound results.

One reason is that the headphone amplifiers in the devices have a very different level of audio quality. When you have a device with a poor internal headphone amp, an external one may help.

The other possibility is a mismatch of impedances. Generally there are two different types of headphone outputs: one with an impedance of around 32 ohms, the other one with an impedance of 120 ohms or more. The first type is used in all low-voltage devices, such as soundcards, MP3 players, mobile CD players, personal stereos and even a lot of stationary CD and cassette players. The second type is used in high-voltage devices: hi-fi components, receivers, amplifiers and some professional equipment such as mixing consoles.

When connected to an output with low impedance, for example 32 ohms, a pair of headphones with an impedance of 16 ohms will produce a higher SPL than headphones with 32 ohms, limited only by the maximum current the amplifier can deliver. However, the 16-ohm headphone will also produce more distortion and will have a poorer bass response. Therefore, headphones with 32 ohms are a good compromise for low-impedance sources. For comparison: at a low impedance output, a 300-ohm headphone has 10 dB less SPL, which means half the loudness, than a 32-ohm headphone.

For connection to a high impedance output, a high-impedance headphone (120 - 300 ohms) is recommended, otherwise the electric energy does not produce SPL but heats the device's resistors (don't worry: the device can't be damaged by the headphones).

If you want to use your headphones for both types of outputs, 64 - 120 ohms will serve it best.

Wireless headphones can additionally be connected to RCA phono sockets. In some countries, such as the USA, TVs don't have headphone jacks. Therefore some Sennheiser RF wireless headphones come with an additional RCA adapter. Please check the product information. You can also get the adapter as an accessory.

I own a pair of wireless headphones which I use for watching TV. However, the headphones switch off with a loud noise after a few minutes of operation. When I switch them off and on again, they work but go off again after a few minutes. What is wrong?

The transmitter of your RF wireless headphone system is fitted with an automatic on/off function. The transmitter is switched on when an audio signal is present at its input, and is switched off when there is no signal. The audio signal, for example from a TV set or a hi-fi system, must have a sufficient amplitude (or level), otherwise the on/off function is not able to detect the audio signal properly. Please set your TV to a higher volume.



Can I leave the BA 90/BA 151 battery in its charger or will it be damaged by overloading?

The charging current is set such that the rechargeable batteries may remain in the charger even when fully charged.



I am looking for a cordless headphone with separate right/left volume adjustment.

The IS 380 infrared headphone system is fitted with a balance control. There are also special TV systems for people with a hearing impairment, such as Set 810 (transmission via infrared light) and Set 820 (RF wireless transmission). These can be specially adapted to the hearing.



How do I set up my RF wireless headphone system?

Please follow the detailed description in the instructions for use. If you have problems with your RS 30 you can also refer to the more detailed RS 40 manual.