As a follow-up to our mechanical evaluation of the Aqua Tower we decided to focus on the acoustical properties of the 5-star hotel lobby of the Radisson Blue, located on the first floor of the iconic building in the heart of Chicago. You can enter the hotel lobby from both the lower level tunnels via an escalator or from the exterior, street level. From the lounge space you can either enter the adjacent bar space or continue on to the gallery. To create the necessary unique acoustic environments in each of the connected spaces, the designers used physical elements as well as altering the ceiling planes and materials within the spaces.
The primary exterior entrance leads you into a large voluminous space which is then fragmented into smaller functions that are controlled by architectural thresholds both physical and implied with finishes. The three primary spaces are a lobby/lounge, bar, and art gallery. We opted to analyze and compare these spaces due to the interesting and challenging design program of having different spaces that demand different acoustic needs within the same physical area. For example, the lounge area seemed to foster intimate conversations and individual comfort, while the bar environment included a good amount of background noise with music and lively interaction among groups; whereas the gallery space had a demand for quiet and peaceful reflection of the surrounding art, all successfully operating during our visit.
The first space you experience is the lobby lounge, which is separated from the bar by large brick columns/ walls with openings and the gallery which is separated by a hanging metal curtain and a set of stairs. Use of brick between the noisy bar and quiet lounge could have been a potential strategy due to bricks’ porous quality, keeping the sound waves within the bar from entering the lounge space. On the other hand, the fact that sound waves can’t pass through bricks means that the noise within the lobby cannot escape and reflects the waves back to the ear. This phenomenon is especially true for large spaces with high ceilings, such as the lounge. Luckily, the lounge also has some softer and less dense materials as this lounge space had a thick carpet which can absorb sound such as the echoes caused by the brick and glass walls within the area. The space was also filled with soft couches and cloth chairs that were taller than the height of the people sitting, which kept the sound from traveling and allowing for more intimate conversations. The side wall was mirrored with a sound-absorbent metal curtain wall which absorbed/diffused a lot of the sound that would had been reflected off the mirrored wall. This space seemed to be occupied by families with children yet still seemed to be a quitter and an acoustically intimate space.
The most lively of the spaces is the bar, which has lower ceilings than the lobby, many different materials and seating arrangements. The wall behind the bar has 3-dimensional convex ceramic tiles that diffuse sound in different directions, helping make the space feel acoustically more natural (seen in figure 1 below). The marble tiles in the bar area also did not provide any sound-absorption. We visited the spaces on Valentine’s Day which was one of their busiest days, yet the space was still easy to hear each other and order drinks. The Bar area was placed on the other side of the lobby lounge and was on a slightly lower level while being separated from the lobby lounge by a corridor approximately ten feet wide. Although greatly minimizing the sound, the music playing in the bar area was still able to be heard whilst standing outside the defined boundaries of the space.
Lastly, we analyzed the Art Gallery space located next to the lounge/bar space for our small space. The area of the space is approximately 25’x100’ with a ceiling height of 11’. The space had polished concrete flooring with drywall for three of the four walls and a metal curtain wall between the space and the adjacent corridor. This curtain helped visually and acoustically separate the spaces as metal is a dense medium. The space was intended for a small group at a time. The space was generally quiet except for small conversations, with most of the time spent silently looking at the art. Despite being right next to the bar area, it was still considerably quieter because it was elevated about 6’ above, connected by a staircase and ramp. There was no acoustic sound proofing that was noticeable from inside of the space, but there was a possibility that the wall adjacent to the bar had sound-absorbing material in-between. During our small conversations while looking at the art we realized some echoing while in the space. We believe this was largely a factor of the surface of the materials within the space and the fact that there was not much furniture or sound absorbing material to soften the sounds. Moreover, the polished concrete flooring also added to the echoing as sound is not absorbed. Instead of using a polished concrete, it would have helped the space if they had used a concrete with a more porous surface in order to convert sound energy to heat thus avoiding the echoing effect.
To sum up, we believe that using appropriate material and different thresholds like level changes, the first floor successfully houses multiple programs that that have different acoustic demands under the same boundaries.
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