Odeon version 4

Auralization

One of the main improvements of ODEON Auditorium, Combined and Combined-Restricted was the inclusion of desktop auralization - allowing aural evaluation and presentation of the predicted room acoustics. The program includes the tools needed to predict the room acoustics in large rooms and to create aural demonstrations of predicted acoustics - all the tools being integrated into an easy to use graphical environment. All you need to run the auralization is a PC with sufficient hard-disk space, a stereo soundcard and a set of headphones. The Industrial edition does NOT include the auralization option.

Binaural filters - calculation principles


The typical point response calculated by ODEON includes more than 50000 reflections per source. The calculation time needed to create a BRIR (Binaural Room Impulse Response), which is the key to the auralization is typically less than one minute per source on a 300 MHz Pentium II. The calculation carried out during the creation of the BRIR's includes full filtering of each reflection in nine octave bands (the 16 kHz band being extrapolated) and applying a set HRTF's (Head Related Transfer Functions) for each reflection. Using the complete filtering scheme as ODEON does has several advantages apart from sounding natural. Not only does the auralization output allow evaluation of the reverberation time, level, speech intelligibility and clarity. It also a allows a reliable evaluation of :

  • High order echoes

  • Directivity and frequency response of sources

  • Envelopment (the experience of being surrounded by sound very much relies on the lateral reflections arriving more than 80 ms after the direct sound

  • Frequency dependent reverberation time. Frequency dependent reverberation is not a question of a simple equalisation of the reverberation, the equalisation is time variant - usually the sound will get darker as sound decays - a very dominant feature of rooms with extreme reverberation times (cathedrals, mosques etc.)

  • Line and surface sources (Combined editions only) may also be handled in a realistic way

  • The sound quality obtained by the ODEON 4.0 auralization is without the traditional artefacts of auralization systems (a typical artefacts of auralization systems are that transient instrument gets to sound gritty or some say 'like pearls on wooden floor'). This is not a dominant problem in ODEON 4.0, because it is capable of obtaining a suitable reflection density and a complete filtering with only modest calculation times - due to a highly optimized filtering process