CIPA 2003 XIX"' International Symposium, 30 September - 04 October, 2003, Antalya, Turkey 
Figure 1. Top: plan of Suleymanie mosque. Bottom: plan of S.Irene. 
The sources are indicated by white circles and receivers by squares. 
Filled black squares are on the balcony and grey ones are in the gallery. 
The drawings are not in scale. 
Task 
Instrumentation 
Generation 
of test signal 
- PC with MOTU2048 soundcard 
- Amplifier 
- Lookline dodecaedric sound source 
Micing of 
sound field 
- Binaural probe Neumann KU100 
- B-format probe Soundfield ST250 
Recording 
of the signal 
- Line preamplifier Tascam MA/AD8 
- Digital recorder Tascam DA38 
Post 
elaboration 
- PC with MOTU2048 soundcard / Laptop 
with Roland UA100 USB Sound Card 
- Cooledit with Aurora package 
Table 1. Chart of the measurement chain employed for the acosutical 
measurements inside the rooms. 
The measurement chain allowed the parallel spatial sampling of 
binaural and B-format data of the sound field created by the 
dodecaedric sound source within the empty rooms and the 
successive off-line post-elaboration. The test signal consisted in 
an exponential sine sweep from 80 to 18000Hz of 20 sec 
duration. The raw data were then digitally stored on magnetic 
tapes via a 20bit digital recorder and later processed for 
calculation of acoustical parameters according to a specific 
technical standard (IS03382, 1997). The sound sources were 
placed 1.25m above the floor whereas the receivers were at 
1.1m. The two sound probes were put side by side at nearly 
0.7m to minimize mutual influence. The calculation of 
acoustical parameters was based on the omnidirectional signal 
enclosed in the B-format coding (called W). The calibration of 
the measurement chain was done by means of a reference 
measurement at the end of each session. In this case the sound 
probes and the source were put on the stage at a fixed distance 
(2m) from each other and height above the floor (2m). This 
measure was used to establish the level of the direct sound with 
respect to the other source-receiver couples. 
3. RESULTS 
3.1 The reverberation time 
Fig. 2 and 3 report the relationship between the measured 
reverberation times in mosques and byzantine churches and the 
volume of the respective enclosures. This is shown for the “all 
pass” and the “mid frequencies” values respectively. 
As expected, the reverberation times in mosques and churches 
show a marked correlation with the increase in volume of the 
enclosure. Nevertheless the mosques and the byzantine 
churches behave differently especially when the volume is 
bigger. In particular the “mid frequencies” in Fig. 3 tell us that 
an higher reverberation time can be expected in churches when 
the volume is larger than 20000m 3 . In the same plot also a set of 
two curves is introduced referring respectively to unoccupied 
and occupied concert halls. It is interesting to see that the 
reverberation time at mid frequencies in mosques is in line with 
that of unoccupied concert halls of comparable volume whereas 
the byzantine churches are generally more reverberant. 
The above plots can also be used to set the predicted 
reverberation time according to volume for a newly built 
mosque. 
Then Figs. 4 and 5 report the dependence of the measured 
reverberation times with frequency for the byzantine churches 
and the mosques. It is seen that the shape of the curves is quite 
different in the two cases.