reported
by: Mr. Jibby Jacob
Secretary (Term
1996/97)
On Thursday, 16 January 1997, a
total of 23 participants from the local audio industry, academics from the
various universities' research groups and undergraduate students attended an
inaugural AES Singapore Section Seminar given by one of its committee
members, Mr. Stephen Low.
After some sumptuous refreshments
and chit chat, Mr. Stephen Low, who is currently a lecturer at the
Electrical Engineering department of the Ngee Ann Polytechnic Singapore,
began his talk. He introduced the audience to the various factors that has
to be considered in the faithful reproduction of bass frequencies. These
included human psychoacoustical response to bass frequency content in music
and film dialogue, specific reproduction needs in computer multi-media work,
cinema sound, audio sound reinforcement and that of high fidelity
reproduction.
After exposing the audience to the
differing psychoacoustical and media requirements, the basics of subwoofer
design through the use of computer modeling and that of the Thiel-Small
Parameters were shared. In this part of the discussion many from the
audience were keen to know how very compact sub-woofer enclosures could be
designed which also yield high acoustical output down to 20 Hz at a
distortion level no greater than 10%. The use of DSP equalisation in the
design of compact closed-box enclosures was also mentioned in brief.
A practical example of a novel
equalisation circuit was introduced using the concept of integratorsTM which
would result in an SPL of at least 110 dB an important requirement for a
true Home Theatre sound experience. In many cases, Stephen noted that sub
audio frequencies were "felt" rather than "heard", that gives the impact in
a film or video sound track.
Being the first audio seminar for
the year 1997 for the Singapore AES Section, it was well received by her
section members and many had actually requested for more such seminars to be
planned for the later part of 1997.
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