thesis/thesis.tex: Adding Halaphon example to introduction. Removing too specific licensing information from introduction.

1 files changed, 33 insertions, 11 deletions

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@@ -326,20 +326,42 @@ parskip=never]{paper}
     not applicable in the case of dynamic setups, reacting to user input in
     realtime.\\
 
-    Generally, software can be divided into two groups: One, which is developed
-    freely and open-source (see~\ref{subsec:whyfreesoftwarematters}) and the
-    other, which is developed non-free, also known as closed-source. Both types
-    are usually covered by a license, explicitely describing the rights of its
-    end-user. In scientific research, free software is usually preferred, due
-    to its ease of reproducability (the sources can be retrieved, modified and
-    used, free of charge).\\
+    Early dedicated hardware implementations, such as the \textit{Halaphon},
+    designed by Hans Peter Haller and Peter Lawo
+    \citep[p.78f]{HansPeterHaller1995}, started out as basic spatial dispersion
+    systems for quadrophonic loudspeaker setups, based on amplitude pannings
+    using envelopes. Due to huge interest from artists in this new technique,
+    these systems were soon expanded to cope with eight and more channels.\\
+    A notable piece, making use of a later revision of the \textit{Halaphon},
+    is Luigi Nono's \textit{Prometeo}. For it, the componist developed the
+    \textit{coro lantissimo}: A choir singing at a great distance. To achieve
+    the effect --- in a usually very dampened orchestra house --- the
+    spatialization system was used to add between eight to 15 seconds of
+    reverberation time in the prolog and up to 20 seconds in the second part of
+    the piece. This enabled a sung \textit{fivefold pianissimo} and a
+    \textit{triple pianissimo} (respectively) to be perceived as coming from a
+    larger distance than the room's dimension \citep[p.
+    91f]{HansPeterHaller1995}.\\
+    This early example of a spatial audio renderer already illustrates the
+    close vicinity of applied scientific research in experimental electronic
+    music studios and that of artistic work, facilitating live electronics.\\
+
+    With the fast technological development of computer systems, the dedicated
+    solutions shifted more into the digital domain and finally towards software
+    solutions. This effectively allowed a stronger focus on specializing and
+    refining the algorithms in use.\\
 
     Spatial audio rendering software exists for different \glspl{os}, in
     several stages of completeness and feature richness, while covered by free
-    and non-free licenses. The following work will focus on free software, used
-    in scientific research and artistic contexts. Several spatial audio
-    renderers, currently in use, were evaluated and compared, of which one was
-    chosen for extension.\\
+    (see~\ref{subsec:whyfreesoftwarematters}) and non-free licenses. The
+    following work focusses on free software, used in scientific research and
+    artistic contexts. Several spatial audio renderers, currently in use, were
+    evaluated and compared (see~\ref{sec:freespatialaudiorenderers}), of which
+    one was chosen for extension.\\
+    Some spatial audio renderers are single-purpose applications, conceived for
+    a specific (and often quite rare) loudspeaker setup, such as those used for
+    \gls{wfs} or \gls{hoa}. An examle of this is the large scale system at
+    \gls{tu-berlin} \citep{website:tu-wfs} or HAW Hamburg.
 
     The \gls{ssr} is a multi-purpose spatial audio renderer, developed at the
     \gls{tu-berlin}. To improve its usability and networking capabilities, a