Sound Acoustics

Mr. Swihart
Current Date: 2/10/14
Due Date: 2/17/14
Acoustics and Psychoacoustics Essay

Today in Survey Recording Technology class, we were taken through a vast

majority of venues, in attempt to exemplify the many different ways of how sound

particles react in many different situations. Some are able to have high chances of

interaction such as reverberation and echoes, while other venues forced the sound to

distribute or even be absorbed. Many areas the class had been taken through also had

large capabilities of reflecting sound completely. The class was taken through two studio

rooms; Studio A and Studio B. Also, the class had the opportunity to witness the

mechanics of sound as it traveled through the two theatres; Gilespy and the Davidson

theatres. The class stood in awe at the acoustics provided in the two stairwells; North and

South. Finally, the class walked eagerly outside to the front of the News Journal Center,

and to the edge of the parking lot.

The very first two rooms that the class was taken two were both studio A, and

studio B. We all gathered around and listened to the crack-like hit of a snare drum fill the

room. In studio A, which was much more dry sounding, had a very “in your face” sound.

Mr. Swihart pounded on the snare drum in the middle of the room, and it sounded like the

crack would immediately refract off the hard, bare, non-treated wall, and would “blow

up” in your face. The floor was a hard wood, so it was also very reflective. However,

once the sound was able to reach the roof, it was dispersed evenly due to the treatment on

the ceiling. The walls were very flat, with very little treatment to help dim the

reverberation. When the snare drum was hit, it sounded very harsh and bright. Compared

to studio A, studio B was much more dense and sounded almost like a deeper, heavier

tone came from the drum when it was hit. Mainly, this was due to all of the absorption of

sound in the room due to the mass amount of treatment. All of the walls were a dense,

noise absorbing material, while there was also very tightly woven fabric covered chairs

all through-out the studio. Studio B was much smaller than studio A, however the noise

almost seemed quieter. There was no decay in sound either. It seemed that once the drum

was hit, it made its sound, and was immediately cut off because of all the dense, flat, soft

walls absorbing most of the remaining noise to cancel out any chance of reverberation.

Two other very interesting and well-acoustically-balanced were the Gilespy Hall,

and the Davidson Theatre. First, the class was brought into the Gilespy Hall. Walking

around, we all observed how the room was almost like a large circle, all centered around

a small, curvy wooden stage. There were many seats throughout the theatre, all of which

seemed to be woven in a tight cloth, like the chairs in Studio B. The walls were also

cloaked in a thick, soft fabric, from which I would think was to help cancel out any

chance of reverberation. Assuming I was going to hear a short dense noise like in studio

B, when the snare drum was hit, the class was in shock at how much of an echo was

made, and which direction of travel it took. The noise was mostly dense like studio B,

however it was not short and cut off. The drum made a very low-pitched echo the roared

through the entire theater. It seemed like the sound was able to reflect immediately off of

the wooden stage, be absorbed into the seats of the theatres, and distribution along the

ceiling corners. From which the noise was gathered in the ceiling corners, the ceiling was

untreated for noise cancellation, so the sound of the drum had a much louder crack up

near the edges of the wall. From these points of the theater are from where the echo came

from. The sound would refract back and forth between ceiling corners, to which is then

eventually absorbed into the lower treated areas of the wall. Compared to the Gilespy

Hall, we also had the opportunity to listen to the acoustics of the Davidson theatre, which

is where most of the orchestra bands have their performances. As we all walk out onto

the stage, it seemed almost silent. Even though this theatre was a very open, wide venue,

it seemed like sound was absent from the space. As soon as Mr. Swihart hit the snare

drum, the only area where we were able to hear sound, was out in the audience seating

area of the theatre. There was almost no noise on the giant wooden stage. On the stage,

which was very hard and wooden, there was a large, smooth wall with tilted tops and

edges for refracting the sound back into the direction of the audience. Mr. Swihart noted

to us that underneath the stage was a very large amount of treatment as well, which

helped absorb all of the possible noise that could happen upon the stage. The audience

portion of the studio was vastly open and untreated. The walls were flat and bare, the

ceiling was tall, and the room was long. There was much room for the sound to echo

throughout. There were tightly woven cloth seats that did have chances of absorbing

some sound, but it was all mostly a long decayed echo. Much like what we heard

previously in studio A, however the sound decayed for a much longer time period.

The two areas that I, along with most of the class, found the most interesting of the

entire news journal center, were the north and south stairwells that Mr. Swihart took us

through. First, we visited the north stairwell in the front of the building. This stairwell

consisted of multiple flat, bare, stone walls, and also giant glass windows peering out into

the parking lot in-front of the building. The stairs were also made of stone, along with the

ceiling above. Everyone walked into the stairwell, a tad afraid at how large the amplitude

of this room may be. As Mr. Swihart hit the snare drum, we heard a very intense amount

of amplitude and reverberation fill the air space around us. The sound was not absorbed

in any way, but fully reflected back and forth between the hard, stonewalls. The noise of

the snare drum sounded as if it were directly smacking you in the face. There was direct

sound, indirect sound, and a small bit of an early sound. Most of which, all noise was

reflecting back and forth of the walls. After, we visited the south stairwell in the back of

the building. The south stairwell, a lot like the north, was mostly concrete stone,

however, this room was fully concrete stone. The stairs, the walls, the ground, the ceiling,

the railing, everything was made out of stone, and this room was about four stories tall,

unlike the first stairwell, which was only two stories tall. Even though in this stairwell,

the direct sound amplitude was very large, the indirect sound was a lot more vibrant than

the first stairwell. With a lot more space and concrete for the sound of the drum to bounce

off of, the sound was able to decay at a very slow rate, due to the lack of absorption from

no wall treatment. In studio B, the hit of the snare was short, direct and heavy. However,

in this stairwell, the opposite took place. This area was a very dry, bright sounding noise,

that echoed on for about seven seconds.

At the end of our tour we, the class, all had a better understanding of how different

sounds and noises react in different venues, with certain materials, and with the amount

of treatment that takes place. We were able to hear and compare all of the similarities and

the differences, and we learned more about amplitude, decay, echo, absorption,

reflection, and all the factors that make certain noises, sound the way that they do. After

this tour of the News Journal Center building, we all had a better understanding of how

the mechanics of acoustics and psychoacoustics work.