Session L Monday, May 14 13:30 - 18:00 hr Room C/D
Chair: Wieslaw Woszcyk, McGill University, Montreal, Canada
13:30 hr L-1
A multichannel sound for a teleconferencing system with
better sound quality and wide-band multichannel sound production, transmission
and reproduction is described. This method has the advantages of the
coincidence of visual and auditory perspective, of the minimum of feedback
a.s.o. The first part treads a modern solution to optimizing the technology of
the multichannel production and the minimizing of echo and noise. The second
part treads the complete solution with large picture. The third part shows the
applications of the principles of the Delta-Stereophony-Systems (SOR) for
multichannel conferencing systems.
14:00 hr L-2
Until now, considerations for the arrangement of
microphones using three frontal channels based on ITU-R BS 755-1 recommendation
assume that three frontal speakers are set up in equal height and equal
distance in front of a listener. Unfortunately in most home applications the
center speaker is not set up as required by the ITU standard. In addition most
of these microphone techniques are not compatible with two channel stereo.
Stereo+C is an arrangement that allows to use normal stereo microphone
techniques with an additional specially arranged center microphone. The entire
arrangement is completely stereo compatible and uncritical in case of a
non-ideal loudspeaker set up at the consumer's home.
14:30 hr L-3
A number of surround sound arrays have been constructed
with closely spaced microphones of cardioid and omni-directional patterns. The spacing and angles between microphones
were calculated to test two different psychoacousticsí models that aim to
provide 360 imaging in a horizontal plane.
A series of controlled subjective listening tests have been undertaken,
and results are presented comparing image localization accuracy and
localization confidence between the arrays.
Results on the effect of cross-talk between opposite microphones in the
arrays are also presented.
15:00 hr L-4
This paper raises a debate about the future options that
are open for multichannel audio metering in Television and Radio Production.
These options are seen both in the light of experience with Movie production,
and also as a part of the wider issue when metering is applied to legacy
applications. In particular, the study questions the continued relevance of
signal level metering within all-digital audio chains. It also concentrates on
the importance of dialogue loudness and intelligibility, when that dialogue may
form an integral part of several different audio delivery packages. Finally,
the visual perceptual aspect of various types of meter display is seen to be an
important but neglected aspect of the overall measurement process.
15:30 hr L-5
Wave Field Synthesis (WFS) is a method to reproduce
spatial sound with a correct localization over a large listening area. It
enables a high quality sound reproduction of sound objects according to, for
instance, the MPEG-4 standard, but also compatible reproduction of 2/0 and 3/2
sound material. Recent developments will be presented concerning true
perspective acoustic reproduction, also in combination with video projection,
making use of different types of loudspeaker arrays, including multi-exciter
16:00 hr L-6
The authors present a new method to extract the mutual
information for data from any number of channels from either a discrete or
continuous system. This generalized mutual information allows for the
estimation of the average number of redundant bits in a vector measurement.
Thus it provides insight into the information shared between all channels of
the data. It may be used as a measure for the success of blind signal
separation with multichannel audio. Several multichannel audio signals are
separated using various ICA methods and the mutual information of each signal
is computed and interpreted. It is also implemented as a contrast function in
ICA for a new method of blind signal separation.
16:30 hr L-7
When binaural sound signals are presented with
loudspeakers, the system inversion involved gives rise to a number of problems
such as, for example, loss of dynamic range and a lack of robustness to small
errors of control performance. These problems for such systems are investigated
and this has resulted in the proposal of a new system, the Optimal Source
Distribution ("OSD") system, which overcomes these problems by means
of variable transducer span. A practical solution to realize a variable
transducer span by discretization is also described. Several examples of the
"OSD" system are demonstrated which in practice produce a very robust
system over the whole audible frequency range. The relationship to the
"Stereo Dipole" system is also described.
17:00 hr L-8
Multichannel sound systems have been extensively used in
sound reinforcement applications and in other large installations but the
overall impact on audiences still remains an unknown at the design stage. This
paper highlights some of the challenges involved in predicting the spatial
reproduction performance of surround sound systems serving large and
acoustically live listening areas and highlights the shortcomings of current
objective assessment methods.
17:30 hr L-9
The problem of production of recordings designated
for surround sound systems becomes a vital problem in sound technology.
Existing standards of surround systems allow for reproduction of spatial sound.
However, there are no consistent recommendations as to which microphone and
mixing technique could be used in specific situations. For the purpose of
research presented in this paper several microphone techniques were employed
for recordings of a quartet playing classical music. The mixing results in
two-channel excerpts and several multichannel ones designated for 5.1
reproduction system. Then, in order to find the most preferable recording
technique these excerpts were used in subjective tests.