reported
by: A/Prof. Gan Woon Seng
Committee Member
(Term 2000/2001)
3D sound has become one of the
most important components in home entertainment, PC gaming, virtual reality
systems, teleconferencing and many others. A seminar on 3D sound was held at
Lecture Theatre 22 in the Nanyang Technological University, Singapore
on 15th December 2000 at 7:00pm. This seminar showcased the
research work carried out by two postgraduate students working on two novel
areas in 3D sound research. These works had also previously been presented
to an international audience during the 109th AES Convention in Los Angeles,
California, USA. A total of 7 members & 17 guests comprising
mainly undergraduate and postgraduate students attended this seminar.
Mr. Tan See Ee
talking to the audience at the NTU Lecture Theatre 22 on "Elevated Speakers
Image Correction using 3D Audio Processing" -
photograph by Mr. Robert Soo.
The first presentation byMr.
Liew Yew-Hin was on the application of psychoacoustics frequency
masking in a cross-talk cancellation system. In a typical surround sound
system, it is very important to cancel the signal that is due to the
loudspeaker in order to generate pressure at the eardrums that appear to
come from a specific elevations and azimuths. In cross-talk cancellation, it
is intended to invert the transmission path of the system. Based on
psychoacoustics masking in frequency domain, the inversion problem is
relaxed, as many perceptual equivalent outputs exist. This paper presents a
scheme that is capable of reducing the power consumption by employing
frequency masking and frequency dependent regularization. A subjective
testing is also conducted to verify the perceptual quality.
|
Mr. Liew Yew-Hin
(left) receiving a speaker's plaque from the Section Chairman, Mr.
Robert Soo- photograph by Mr. Christopher
Yap. |
Mr. Tan See Ee
(left) receiving a speaker's plaque from the Section Chairman, Mr.
Robert Soo- photograph by Mr. Christopher
Yap. |
The second presentation by
Mr. Tan See Ee described a possible solution in multi-speaker
placement in a home entertainment system. Due to the ever-increasing number
of loudspeakers in the latest surround sound system, such as the Dolby
Digital and Dolby E, user is faced with a problem of placing their speakers
and concealing the wires in the living room. A neat solution is to place the
loudspeaker near the ceiling and also able to hide the wires in the
ceiling. But a problem with this setup is that the speaker is no longer at
ear-level and this creates a visual-auditory image mismatch in watching
movie. A novel method has been introduced to compensate for this distortion,
which tricks the ear into believing that the ear is listening to sound
coming from the ear-level, instead from the elevated positions. A real-time
processing system running on the latest DSP has also been implemented for
2-speaker and multi-speaker configurations.
AES Singapore
Section's members and guests comprising of mainly students from NTU after
the talk by Mr. Liew Yew-Hin (front row, fourth from left with glasses) and
Mr. Tan See Ee (front row, sixth from left with glasses)
- photograph by Mr. Christopher Yap.
After the presentation, there were
several interesting questions related to the psychoacoustics phenomenon,
such as the application of temporal and frequency masking used in the 3D
audio system. There were several questions on the position of loudspeakers
to create different perceptual impression and also the inclusion of
reverberation to enhance the auditory image. Discussion with the presenters
continued till 9:30 pm. |
