AVQ Automatic Volume and eQualization control Interactive White Paper v1.6

The problem and solution Mobile phones Hands-free kits Car radios Portable Media Players Comfortable reproduction of music or speech in varying noisy conditions requires constant changes in sound level (with changes in noise level) and equalization (with changes in noise spectrum). For example, the volume and equalization set for a standing car will no be adequate when the car is moving. Today, the user has to change the sound volume manually which is uncomfortable and, in some cases such as a hands-free car kit, even dangerous. Suitable manual frequency equalization is almost never possible due to a large number of parameters to control “on the fly”. Automatic Volume eQualization control (AVQ) technology provides an automatic alternative to manual volume and equalizer adjustment. It permanently monitors noise conditions and changes the sound being reproduced accordingly. Figure on the right shows the basic AVQ scheme. A microphone (already present in communication devices) is used to monitor the current noise conditions. The signal being equalized is divided on several frequency subbands. The microphone signal is divided on the same frequency subbands and analyzed to extract noise level in each subband without being affected by the loudspeaker sound. The parameters are then fed into the corresponding band equalization (gain) blocks. These blocks dynamically amplify and equalize the sound to be head equally well in varying noisy conditions ensuring sufficient but not excessive signal to noise ratio over all frequency range . Decomposition on subbands Band Noise Estimation Band EQ 1 Gain > 1 Band EQ N Gain = 1 Combining from bands Noise level Signal and noise before Signal and noise after Input signal Mic signal Demo ahead Revision: 2.0

The figures below illustrates the performance AVQ Performance The figures below illustrates the performance The left figure shows sound and noise level in quiet conditions (e.g. in a standing car). The volume and equalization of speech is set to be heard well (all above the noise level but not too much). The middle figure shows the same speech level while the noise level and its spectrum has changed (moving car). It is seen that parts of the speech spectrum are masked by noise. Accordingly, the speech intelligibility is reduced dramatically. The right figure demonstrates the spectrum of noise and equalized speech. Similar to the left figure, the speech exceeds the noise level all over the frequency range (but not too much). This restores intelligibility and provides a comfortable sound. AVQ may also be called “Audio Cruise Control” as it totally eliminates the need to touch sound controls while “cruise” conditions are changing. Demo on the next slides Revision: 2.0

AVQ processing for voice communication Being a part of Alango Voice Communication Package of technologies (VCP), AVQ technology is tightly integrated with other Alango signal processing technologies. It shares the same subband decomposition and noise estimation blocks. Demo conditions: - Varying background noise is an ambient noise around the user. It cannot be changed/reduces as the DSP system has not control of it. - Voice reproduced by the phone speaker is equalized according to the spectrum and power of the ambient noise to provide equal intelligibility and perceptual loudness. Voice in ambient noise without processing Bulldozer Helicopter Press any key to hear unprocessed sound Voice in ambient noise with AVQ processing Bulldozer Helicopter Press any key to hear sound with AVQ Revision: 2.0

AVQ-Me processing demo for music AVQ for Music and Entertainment (AVQ-Me) is devoted to those listening music, watching movies and using their game consoles in mobile environments. While ambient noises change fast and unpredictable, you just don’t have time to stop. AVQ-Me does all for you, so enjoy your music, always. Processed by AVQ-Me technology Without AVQ-Me Noise in the examples is ambient noise. AVQ-Me cannot reduce or change it, it amplifies and equalizes the music instead AVQ for Music and Entertainment (AVQ-Me) technology uses its own subband decomposition scheme that is optimized for high quality music reproduction in such devices as portable media players, mobile phones and car stereos. Revision: 2.0