IS 2526:1963 is the Indian Standard (BIS) for the acoustic design of auditoriums and conference halls. This standard provides guidelines for the acoustic design of auditoriums, conference halls, and cinemas to achieve optimal speech intelligibility and music clarity. It outlines recommendations for room volume, shape, reverberation time calculations, seating arrangements, and the strategic placement of acoustic treatments to mitigate defects like echoes and sound foci.
Code of practice for the acoustic design of auditoriums and conference halls
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Optimal RT (Speech - Conference Hall, ~300 m³) | Approx. 0.8 - 1.1 s (at 500 Hz, for 'fully occupied' state) | Approx. 0.7 s ± 20% (mid-frequencies) | DIN 18041:2016 |
| Optimal RT (Music - Auditorium, ~5000 m³) | Approx. 1.5 - 1.8 s (at 500 Hz, for 'fully occupied' state) | Approx. 1.9 - 2.2 s (mid-frequencies, for classical music) | DIN 18041:2016 |
| Background Noise Level (Auditorium) | 35 - 40 dB (unspecified weighting, likely dBA) | NR 25-30 (Noise Rating curve), approximately 30-35 dBA | BS 8233:2014 |
| Low-Frequency RT characteristic (Music) | Recommends RT at 125 Hz may rise by up to 20-30% compared to 500 Hz. | Targets a specific 'Bass Ratio' (RT at 125+250Hz / RT at 500+1000Hz) of 1.1 to 1.3 for symphonic music. | Common practice based on ISO 3382-1 parameters |
| Volume per Seat (Cinema) | Recommended range: 3.4 to 5.6 m³ per seat. | No longer a primary design metric; focus is on achieving specific RT and noise level targets regardless of volume per seat. | General modern practice |
| Frequency Range of Analysis | Primarily focused on 500 Hz, with some consideration for 125 Hz and 2000 Hz. | Typically requires analysis in octave bands from 125 Hz to 4000 Hz or 8000 Hz. | ISO 3382-1:2009 |