1. A listener position adaptive stereo
system for object based reproduction
Teófilo de Campos and Adrian Hilton
CVSSP, University of Surrey, UK
Marcos F. Simón Gálvez*, Dylan Menzies and Filippo Maria Fazi
ISVR, University of Southampton
* M.F.Simon-Galvez@soton.ac.uk
• Sweet spot independent reproduction leading to an extended listening
experience.
• Audio object reproduction with listener tracking allows to create
parallax cues.
• The system has been implemented in MAX MSP 6. At the moment we
are performing subjective tests to further test the operation of the
formulation.
Object Based Audio Reproduction
lR (1)
Source RSource L
Pos. 1
Pos. 2
lR (2)lL (2)
lL (1)
gL (1) gR (1)
p(1)
gR (2)
gL (2)
p(2)
Conclusions
Stereo Reproduction
Enhancing the Sweet Spot
• Stereo reproduction allows for the creation of strong virtual images
when the listener is placed at the sweet spot, a small area in the centre
of symmetry between both loudspeakers.
• If the listener is outside of the sweet spot the localisation tends
towards the nearest loudspeakers and the virtual images are
deteriorated [1].
• The loudspeaker feeds can be
compensated by monitoring
the position of the listener
with respect to the
loudspeakers.
• This can be performed by using
a computer vision system
which tracks the position of the
listener.
References
r'Rr'L
d
x'
Y-Axis
X-Axis
Source RSource L
C
• Based on the vectors of position with respect to the loudspeakers the
left and right input signals are compensated according to
• This allows the sound waves propagating from both loudspeakers to
arrive to the listener position at the same time
20 21 22 23 24 25
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
Samples, (n)
IR,(V)
• The localisation of the stereo
mix is preserved independently
of the listener position, which
otherwise will be lost as the
listener moves.
• This was previously achieved
by the Sweetspotter [2].
20 21 22 23 24 25
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
Samples, (n)
IR,(V)
• Object based audio reproduction
can be obtained using VBAP and
VBIP techniques [3,4,5].
• The combination with video
tracking allows to create robust
parallax cues, as the panning
gains are updated every time the
listener moves.
• Panning gains are calculated according
to:
• According to Gerzon’s localisation theory [4,6] summing localisation
is frequency dependant. To this end, the panning gains are
normalised independently for low and high frequency (above and
below 1.5 kHz).
-1.5 -1 -0.5 0 0.5 1 1.5
-2
-1.5
-1
-0.5
0
0.5
x, (m)
y,(m)
Object
LF Panning
HF Panning
Source L
Source R
-1.5 -1 -0.5 0 0.5 1 1.5
-2
-1.5
-1
-0.5
0
0.5
x, (m)
y,(m)
LF Panning
HF Panning
Source L
Source R
x, (m)
-1.5 -1 -0.5 0 0.5 1 1.5
y,(m)
-2
-1.5
-1
-0.5
0
0.5
1
Object
LF Panning
HF Panning
Source L
Source R
x, (m)
-1.5 -1 -0.5 0 0.5 1 1.5
y,(m)
-2
-1.5
-1
-0.5
0
0.5
Object
LF Panning
HF Panning
Source L
Source R
• Low frequency localisation (LF) is extended outside of the
loudspeaker span. High frequency (HF) localisation is kept inside the
loudspeaker span.
1. B.B. Bauer, “Broadening the area of stereophonic perception”, J. Audio Eng. Soc, vol. 8, no. 2, pp. 91-94, 1960.
2. S. Merchel and S. Groth, “Adaptively adjusting the stereophonic sweet spot position,” J. Audio Eng. Soc, vol. 58, no. 10, pp. 809-817, 2010
3. V. Pulkki, “Virtual sound source positioning using vector base amplitude panning,” J. Audio Eng. Soc, vol. 45, no. 6, pp. 456–466, 1997.
4. J. marie Pernaux, P. Boussard, and J.-M. Jot, “Virtual sound source positioning and mixing in 5.1 implementation on the real-time system
genesis,” in In Proc. Conf. Digital Audio Effects (DAFx-98, 1998, pp. 76–80.
5. P. Lemieux, R. Dressler, and J. Jot, “Object-based audio system using vector base amplitude panning,” Dec. 5 2013, Patent App.
PCT/US2013/043,150.
6. M. A. Gerzon, “General metatheory of auditory localisation,” in Audio Engineering Convention 92, Mar 1992.
x, (m)
-1.5 -1 -0.5 0 0.5 1 1.5
y,(m)
-2
-1.5
-1
-0.5
0
0.5
Conventional Stereo
Listener compensation
Source L
Source R