Sennheiser HD 4.40BT Faq

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What does "Circumaural" mean?
CIRCUMAURAL headphones (sometimes referred to as "Around Ear" headphones)
encircle the ear creating a seal thereby effectively reducing ambient noise from getting to
the ear. This is known as passive noise reduction.
This type of headphone is most effective in a high noise environment where it's necessary
to eliminate as much of the environmental noise as possible for effective communication.
HD 4.40BT ( #506782 )
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How do I get the best transmission range out of my wireless headphones?
While the overall transmission range for wireless headphones is mostly determined by the
wireless technology being utilized by the individual wireless headphone product there are
multiple external factors (like obstacles, audio signal strength, wireless signal congestion,
etc) that can effect the wireless signal transmission range of wireless headphones.
Obstacles are one of the main factors that can effect the transmission range of the
wireless signal. While the wireless signal (with the exception of infrared signals) can pass
through obstacles (like walls) ultimately range will be affected (likely reduced) by
passing through these obstacles and the more dense the obstacle the greater the effect will
be on the signal. For example a signal passing through a glass window won't be affected
very much whereas a signal passing through a concrete wall will be effected much more
greatly. Having a clear line of sight does provide the best transmission range.
The audio signal being output by your audio source to the transmitter of the headphones
is another key factor in transmission range. A weaker audio signal going into the
transmitter means the transmitter has a weaker signal to work with which can in turn
reduce the transmission strength which ultimately affects range. Ensure that your audio
source is outputting the best possible signal for the transmitter to use.
HD 4.40BT ( #506782 )
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What is A2DP and what does it do?

A2DP (Advanced Audio Distribution Profile) is a Bluetooth profile that defines how
multimedia audio can be streamed from one device to another over
a Bluetooth connection.
FAQ