Building The Room Right For Acoustics

When focusing on the soundproofing home theater and acoustic treatment, it is seen that most engineers focus on the kind of material used in the room. Along with paying attention to the kind of acoustical foam and acoustical panels used in the room, one also has to pay the right attention to the structure of the room so as to make it just right for the caustics to work. An acoustically right room will allow the electronics and other measure s taken to work effectively and get the desired results.

It is not a very good idea to solely make the acoustical treatment depend on electronics. It is often seen  that people spend hundreds and thousands of dollars on expensive and sophisticated equipment to make  room corrections. Auditorium acoustics design tends to get even more complex and expensive, if following this methodology. While equalization and use of expensive equipment can make the sound get better in the room, one is basically not working on the laws of physics here and making the alterations superficially. Keep in mind that a room is an active environment and it is going to resist whatever acoustic changes we make.

When we increase the absent frequency in the room, we are also increasing the level of the out-of-phase reflection in the room. Auditorium acoustics architectural design experts explain with the help of a simple science experiment. For example, they use a driver loudspeaker, an amplifier and a frequency oscillator and use the amplifier to feed the 1000 Hz tone. Now, if you reposition the speaker, facing him towards a hard, flat surface about -3/4 inches away, you will find the sound completely disappearing. This happens as the wavelength of the sound is 1000 Hz and the distance is about one half wavelength. The reflected energy gets about 180 degrees out of sync with the source of the sound. 

If we increase the source signal level, this will always lead to a corresponding rise in the reflected signal level. Practically, the reflected signal gets lesser in intensity and some of the strength of the signal gets absorbed and diminished over distance. During those old days,  when we were increasing playbacks and recording tracks, there was also a growing awareness on acoustics. The mixed sound would sound different in a room, in a car and the studio. Acoustic auditorium specialists have seen great variation in sounds in different rooms with the same facility.

The rooms working only on the equalization correction and covered only the engineer’s position often had to bear with complaints from the audience and the musicians as well as the artists. They could affect the acoustics of the room by simply being there. Therefore it is more important to focus on the designing of the room to get the right acoustic solutions.

John is a well known wrier and has written many articles on auditoriums and acoustical ceiling tiles. Here he sheds light on how to focus on the structure of the room rather than just making changes with the electronics.