Philips PSC60417 Release Note page 6

3. Virtual 5.1 Channel Surround: From 5.1 channel sources
such as multi-channel software DVD players,
QSurround virtualizes each channel for dynamic
reproduction through stereo speakers. In addition,
QSurround enhances playback through multi-channel
5.1 speakers for a seamless and more immersive
surround experience.
Attacking MP3 Format Limitations.
QSizzle and QRumble are audio frequency response modifiers.
This technology is in the same general category as tone
controls and equalizers (i.e. filters). However, whereas
conventional filters are static, QSizzle and QRumble are active.
Static filters apply a fixed change to the input signal according
only to their user settings, without regard to the nature of the
sound input signals. For example, if a bass tone control is set
by the end user to provide a given boost amount, this boost
amount, and the shape of the filter curve (boost vs. frequency)
remain constant over time, regardless of the instantaneous
characteristics of the audio input signal itself. In a sense, the
filter "ignores" the signal and blindly makes its assigned
modification.
Static filtering must be judiciously applied. With more dramatic
filtering, i.e. high boost levels, a truly artificial tonal characteristic
is imparted. This is perceived by the listener (consciously or
unconsciously, according to their level of sophistication) as
being systemic – that is, separate and independent of the
content. Second, increased boost also carries a higher risk of
overload distortion, requiring more frequent user adjustments
to deal with extremely variable content.
QSizzle and QRumble are active filters – their response varies
dynamically, in real time. Unlike the classic bass and treble tone
controls, both QSizzle and QRumble are composed of
multiple independent processing channels. Each channel
applies variable dynamic emphasis in accordance with the
audio input signal. In direct contrast to static filters, user
settings for QSizzle and QRumble provide guidelines for the
desired effect, rather than fixed rules. The instantaneous
degree and frequency weighting of the emphasis are
controlled by the input signal itself. This use of content to
control emphasis results in highly correlated, natural sounding
Philips Electronics White Paper
Page 6 of 9