H04S1/00	7	Two-channel systems (H04S5/00, H04S7/00 take precedence)	H04S1/00	H04S1/00		1148
H04S1/002	8	{Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution (control circuits for electronic adaptation of the sound field H04S7/30)}	H04S1/00	H04S1/00		1074
H04S1/005	9	{For headphones}	H04S1/00	H04S1/00		553
H04S1/007	8	{in which the audio signals are in digital form (data reduction aspects thereof based on psychoacoustics G10L19/02)}	H04S1/00	H04S1/00		1008
H04S3/00	7	Systems employing more than two channels, e.g. quadraphonic (H04S5/00, H04S7/00 take precedence)	H04S3/00	H04S3/00		1573
H04S3/002	8	{Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution (control circuits for electronic adaptation of the sound field H04S7/30)}	H04S3/00	H04S3/00		742
H04S3/004	9	{For headphones}	H04S3/00	H04S3/00		295
H04S3/006	8	{in which a plurality of audio signals are transformed in a combination of audio signals and modulated signals, e.g. CD-4 systems}	H04S3/00	H04S3/00		162
H04S3/008	8	{in which the audio signals are in digital form, i.e. employing more than two discrete digital channels (data reduction aspects thereof based on psychoacoustics G10L19/02)}	H04S3/00	H04S3/00		2035
H04S3/02	8	of the matrix type, i.e. in which input signals are combined algebraically, e.g. after having been phase shifted with respect to each other	H04S3/02	H04S3/02		701
H04S5/00	7	Pseudo-stereo systems, e.g. in which additional channel signals are derived from monophonic signals by means of phase shifting, time delay or reverberation&#160;	H04S5/00	H04S5/00		900
H04S5/005	8	{of the pseudo five- or more-channel type, e.g. virtual surround}	H04S5/00	H04S5/00		458
H04S5/02	8	of the pseudo four-channel type, e.g. in which rear channel signals are derived from two-channel stereo signals	H04S5/02	H04S5/02		391
H04S7/00	7	Indicating arrangements; Control arrangements, e.g. balance control	H04S7/00	H04S7/00		1067
H04S7/30	8	{Control circuits for electronic adaptation of the sound field}	H04S7/00	H04S7/30		2413
H04S7/301	9	{Automatic calibration of stereophonic sound system, e.g. with test microphone}	H04S7/00	H04S7/30		1521
H04S7/302	9	{Electronic adaptation of stereophonic sound system to listener position or orientation (H04S7/301 takes precedence)}	H04S7/00	H04S7/30		2009
H04S7/303	10	{Tracking of listener position or orientation}	H04S7/00	H04S7/30		2188
H04S7/304	11	{For headphones}	H04S7/00	H04S7/30		1603
H04S7/305	9	{Electronic adaptation of stereophonic audio signals to reverberation of the listening space (H04S7/301 takes precedence)}	H04S7/00	H04S7/30		1125
H04S7/306	10	{For headphones}	H04S7/00	H04S7/30		337
H04S7/307	9	{Frequency adjustment, e.g. tone control (H04S7/301 takes precedence)}	H04S7/00	H04S7/30		1064
H04S7/308	9	{Electronic adaptation dependent on speaker or headphone connection}	H04S7/00	H04S7/30		399
H04S7/40	8	{Visual indication of stereophonic sound image}	H04S7/00	H04S7/40		643
H04S2400/00	7	Details of stereophonic systems covered by H04S but not provided for in its groups	CPCONLY	H04S2400/00		6
H04S2400/01	8	Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved	CPCONLY	H04S2400/01		1596
H04S2400/03	8	Aspects of down-mixing multi-channel audio to configurations with lower numbers of playback channels, e.g. 7.1 -&gt; 5.1 (H04S2400/01 takes precedence)	CPCONLY	H04S2400/03		505
H04S2400/05	8	Generation or adaptation of centre channel in multi-channel audio systems	CPCONLY	H04S2400/05		239
H04S2400/07	8	Generation or adaptation of the Low Frequency Effect [LFE] channel, e.g. distribution or signal processing	CPCONLY	H04S2400/07		140
H04S2400/09	8	Electronic reduction of distortion of stereophonic sound systems	CPCONLY	H04S2400/09		170
H04S2400/11	8	Positioning of individual sound objects, e.g. moving airplane, within a sound field (H04S2420/13 takes precedence)	CPCONLY	H04S2400/11		2743
H04S2400/13	8	Aspects of volume control, not necessarily automatic, in stereophonic sound systems	CPCONLY	H04S2400/13		1300
H04S2400/15	8	Aspects of sound capture and related signal processing for recording or reproduction	CPCONLY	H04S2400/15		1750
H04S2420/00	7	Techniques used stereophonic systems covered by H04S but not provided for in its groups	CPCONLY	H04S2420/00		10
H04S2420/01	8	Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF&apos;s] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD]	CPCONLY	H04S2420/01		2665
H04S2420/03	8	Application of parametric coding in stereophonic audio systems	CPCONLY	H04S2420/03		800
H04S2420/05	8	Application of the precedence or Haas effect, i.e. the effect of first wavefront, in order to improve sound-source localisation	CPCONLY	H04S2420/05		76
H04S2420/07	8	Synergistic effects of band splitting and sub-band processing	CPCONLY	H04S2420/07		465
H04S2420/11	8	Application of ambisonics in stereophonic audio systems	CPCONLY	H04S2420/11		783
H04S2420/13	8	Application of wave-field synthesis in stereophonic audio systems	CPCONLY	H04S2420/13		286
