2 Description
Professional quality processor The HEARO 888 DIGITAL is a UHF transmitter designed specifically for use with HEARO DIGITAL wire- less headphones from AKG. Outputs for hardwire stereo headphones and loudspeakers allow the unit to be used in professional recording studios as well. The heart of the HEARO 888 DIGITAL is a high quality digital signal processor whose high resolution ensures optimum sonic results with both analog and digi- tal program material.
Universal interfacing The HEARO 888 DIGITAL provides analog and a coaxial digital input for easy interfacing with analog out- puts on audio, video, TV equipment or PCs as well as coaxial digital outputs on DVD and CD players or digital TV sets.
Digital signal processing Analog signals are digitized immediately after the input stage. All signal processing that affects the sound takes place in the digital domain. This maintains the full dynamic range of the input signal and minimizes noise. Digital signals remain in the digital domain from the source to the headphones to ensure the high- est possible audio quality.
Digital signal transmission The signal is transmitted in its digital form to the receiver in the wireless headphones. Conventional dig- using ACS Audio Coding ital audio signal transmission techniques delay the signal by about 60 to 100 milliseconds due to the System required data processing. As a result, TV or video sound may seem slightly out of sync. The ACS Audio Coding System developed by AKG is he first technique that reduces the time delay to approximately 5
milliseconds so that there will be no noticeable delay between picture and sound.
Digital receiver The receiver built into the headphones converts the received digital signal into an analog audio signal. The greatest advantage of digital over analog transmission is that it requires neither an automatic gain control (AGC) nor a compander system. This maintains the full original dynamic range of the audio sig- nal. Other benefits of this process include minimum noise, better
Reflections of the transmitter signal off metal objects etc. may weaken or even cancel the transmitter sig- nal in some places
Acoustic status indicator If the transmitter and receiver are tuned to different frequencies or if you are too far from the transmitter, you will hear a beep in the headphones.
UHF headphones available The HEARO 888 DIGITAL system lets you share your listening enjoyment with other persons. You can separately operate your transmitter with several digital headphones simultaneously. Make sure to use digital wire-
less headphones operating in the same UHF frequency band as the HEARO 888 DIGITAL.
2.5IVA Individual Virtual One drawback of headphone listening is the psychoacoustic phenomenon of "inside localization": the Acoustics orchestra seems to play inside your head rather than in the room. AKG developed a binaural audio pro- cessing technique called IVA (Individual Virtual Acoustics) that models the way the head and pinnae change the arriving sound waves (ear matching function). Thus, the various sound sources will seem to
be located outside your head even when you are using headphones.
A: Natural hearing: Due to the effect of the head and pinnae, sound waves arriving at one ear differ from those arriving at the other. Amplitude and phase differences create a sense of spatial hearing.
B: Listening through headphones: Amplitude and phase differences are eliminated. Sound sources are localized inside the head rather than in the room.
| C: Listening through headphones with IVA processing: The ear |
| matching function modifies the audio signals at the ears to resemble |
LH FILTER | diagram A. This restores natural, spatial hearing. |
RH FILTER |
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HEARO 888 DIGITAL
