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Reverberant space demo

A reverberant space— what difference does it make?

Click on hyperlinked text (underlined blue) in the table below to play sound examples from ODEON 8.5 auralisation, details explained below.

Hint: Start with one of the Dry examples. Then, without closing your wav-player, click one of the Live examples, to hear the difference. For example, note the different liveness in the rehearsal room compared to platform, and the different liveness from an ensemble of unison violins compared to solo violin in the same acoustic conditions.  

Explanation

All sound examples (2MB *.wav each) are simulated in ODEON 8.5 with the following conditions:

 

Live: 20.000m³ concert hall, 1600 seats, 85% occupied, 100 p orchestra, RT=1.8s at 1kHz

Dry: All room surfaces except audience and orchestra are fully sound absorbent

Audience: Listening position in front half of stalls, 14m from source (in center of orchestra)

Performer: Listening position is 1m from source, Performer Live is in center of orchestra platform

Rehearsal: Listening position is 1m from source, in a 280m³ rehearsal room for groups, RT=0.7 s

Ensemble: Listening position in the middle of a 100p violin ensemble playing in unison

 

Each example is associated with a physical value to characterize objective reverberance— EDT (s) for listeners perceived reverberance, and ST_late (dB) for performers perceived reverberance.

For further orientation, a value that characterizes envelopment is included, and for the purpose of this demonstration defined as Relative LG (LG is average late lateral energy in 125-1000Hz arriving later than 80ms re direct sound) related to average G in 125-1000Hz, RLG=LG-G_avr. Musical clarity, C80 denotes level balance between early and late energy. More info about EDT, ST_late , LG and C80 on the akuTEK page Parameters.

“-” denotes that a value is either not defined or outside a range that is reliable or verifiable by measurements. The music is from Mendelssohn Violin Concerto, and all examples are solo violin, except “Ensemble” which is synthesized from a solo violin recording.

 

Note the different RLG (listener envelopment) values accompanying the different aural impressions of Performer Live

and Performer Live Ensemble, which is due to the fact that the change from solo to unison ensemble brings more increases to late sound energy than it does to early/direct sound energy, as can be seen from C80 values.

 

To normalize recording levels for your convenience, Audience examples are boosted with 16dB to compensate for long source receiver distance, and Ensemble examples are attenuated with 8dB to avoid large ensemble in unison to overload the recording. This should be kept in mind if comparing Audience with Performer, or Performer Ensemble with Performer.

Figure 1 shows diagrams of sound-pressure vs time for the examples Audience Dry (top) and Audience Live (bottom).  The level difference due to room acoustic reinforcement is evident. If the two examples are normalized to give the same peak levels, as in Figure 2, the differences due to the whole character of the sound becomes prominent . Reverberation makes the diagram smoother by filling in weak parts with sound energy, but still maintaining peaks.

Figure 1

Figure 2

Interested in visual demonstration of room acoustics? More info about Acoustic Visualization and exploring the acoustics of a concert hall with the Audio Camera via this external source: Visualizing Concert Hall Reverberation.

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