The Analysis of Room Acoustic Parameters of Karaoke Rooms in Surabaya

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Journal of Physics: Conference Series

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The Analysis of Room Acoustic Parameters of Karaoke Rooms in Surabaya

To cite this article: Susilo Indrawati et al 2021 J. Phys.: Conf. Ser. 1951 012036

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International Symposium on Physics and Applications(ISPA 2020) Journal of Physics: Conference Series 1951 (2021) 012036

IOP Publishing doi:10.1088/1742-6596/1951/1/012036

The Analysis of Room Acoustic Parameters of Karaoke Rooms in Surabaya

Susilo Indrawati^a, Vina Dwi Arinie, Anis Nuryaqin, Gontjang Prajitno, Suyatno, Lila Yuwana^b

Department of Physics, Faculty of Sciences and Data Analytics, Institut Teknologi Sepuluh Nopember, Kampus ITS Sukolilo - Surabaya, Jawa Timur 60111 Indonesia

E-mail: ^a[email protected], ^b[email protected]

Abstract. This research is performed to evaluate the acoustic parameter and noise of several karaoke rooms in Surabaya. The type of rooms can be classified into small rooms and large rooms. All the measurements were conducted at 12:00 to 16:00 GMT+7:00. Based on the measurement results, noise criteria (NC) values range between 45 and 50. These values are quite high if compared to standard NC value, i.e., 25. This statement is in accordance with the low values of noise reduction (NR) of evaluated rooms: walls with glass accessories (12 – 16.5 dBA);

door gap (8 – 13.9 dBA); wall (10 – 18 dBA); and door hinge (6.9 – 9 dBA) in the frequency of 1000 Hz. Therefore, the low values of NR lead to NC value exceeds the recommended value.

According to the observation and the analysis, we obtain there are some rooms using special doors that are very well to absorb noise. However, those doors still have a drawback because they are equipped with glass which has a low value of NR. The addition of glass to the doors reduces NR value. Moreover, the ranges of reverberation time of small rooms and large rooms are 0.3 – 0.4 s and 0.6 – 0.7 s, respectively. This difference range is caused by the volume of rooms. In addition, the speakers of all rooms are the same, i.e., woofer speakers. It could be understood from the sound spectrum that has a range of 100 – 500 Hz. Lastly, all the analyzed rooms have a high value of noise. The measurement results 94 𝑑𝐵𝐴 of 𝐿_𝑒𝑞 and 104.3 𝑑𝐵𝐴 of 𝐿_𝑚𝑎𝑥. Regarding the health regulation, the sound that has those intensities is harmful to the human hearing.

1. Introduction

The number of entertainment places has been increasing in downtown. The advancement of technology truly influences on the wide variety of entertainment places. One of the favourite entertainment places is karaoke room. This is because karaoke room relatively could be relished by most people.

As the increasing the number of karaoke places, the improvement of quality and safety of karaoke room is really required. Consequently, the analysis of acoustical aspect should be conducted to examine karaoke rooms. The first research on karaoke rooms was performed by Min Young in Korea in 2015 to evaluate noise level of karaoke in Korea and the impact to hearing safety [1]. The result was the noise level of karaoke in Korea exceeds the recommended threshold, i.e., 115 dB.

According to Mc-Graw Hill Dictionary of Scientific and Technical Terms, a noise is an unwanted sound. This unwanted sound is usually caused by very loud sound. Therefore, most people should realise the existence of noise that could be harmful for their hearing health [1][2]. For instance, a person who has difficulty to take a rest because the surrounding is very noisy from a heavy traffic. If this problem still prolongs, then the hearing health could be gradually deteriorated. Moreover, it could be a permanent hearing loss [3][4].

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Not only as an entertainment place, but karaoke is also used as a place to build and increase interest in reading such as fluency and motivation to overcome difficulties in reading [5]. Moreover, for examining of singing skills " Enthusiasm to sing" in evaluating the singing voice of amateur singers [6], as well as can be done karaoke online [7]. The development of new technology is using karaoke as a language classroom [8].

In this research, we consider observing small room and large room which have significant different acoustically. The observation of karaoke rooms involves the analysis of room acoustic parameter and a noise. Advantageously, this research will turn out the problem that could exist in the karaoke room related to the hearing health. Lastly, this research also provides a recommendation scientifically to improve the acoustical parameters of karaoke rooms.

2. Methodology

As explained before, in this study will analyse acoustic parameters and noise in small room and large room types of karaoke room. The steps are as follows:

2.1 Observations

In the initial observation step, space dimension measurement is performed to determine the measuring points. In addition, we were also listing materials contained in karaoke rooms and measuring the area of the materials. There are 2 kinds of karaoke rooms observed here, namely karaoke room A and karaoke B with small room and large room type. The materials used in the karaoke room can be seen in Figure 2.1.

a b

Figure 2.1 Two types of karaoke room: a large room b. small room

The volume of karaoke room used (Figure 2.1) each room for large room is 54.93 m³ with room capacity of 15 persons. While the small room type has a volume of 25.7 m³ with a room capacity of 5 persons. It seemed in the karaoke room there are several ornaments to show the aesthetic. Glass as embellishment has the impression of a spacious looking space, while the decoration has a contemporary value to make visitors interested.

2.2 Data Retrieval

This research will examine acoustic parameters of the karaoke room. Therefore, we will acquire data related to acoustic parameters needed. The parameters that will be measured as follows.

2.2.1. Background Noise (BN) measurement on karaoke rooms

BN measurement is conducted with 6 measuring points, where points 1 to 4 were in seats and 5 to 6 were under speakers. The height of microphone points 1 to 4 was 1.2 meters and the height of microphone point 5 and 6 was 1.5 meters from the floor. The height of this measuring point follows the average height of the human ear, where for points 1 to 4 that is the height of the ear when sitting and points 5 to 6 is the height of the human ear when standing. The measurement scheme can be seen in Figure 2.2 below.

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Figure 2.2 The measurement of background noise.

The measurement of BN is performed to obtain criteria noise curve. therefore, we can measure precisely how much noise caused by surrounding environment.

2.2.2. Reverberation Time (RT) Measurement

The reverberation time (RT) measurement points is the same as the BN measurement, i.e. with 6 points, as shown in Figure 3. In RT measurement using the sound source of the impulse response is a exploded balloon located between points 5 and 6. The recording the exploded balloon will be captured to YMEC software to analyze RT calculation.

2.2.3. Noise Reduction (NR) Measurement

NR measurements are carried out on doors, glass, and walls. This measurement was used to determine the level of sound leakage of the karaoke room. This measurement was performed with a white noise source in a karaoke room that is rung with speakers. The measurement was using 4 outdoor points and 4 indoors points. Point 1 is located on the glass, point 2 gaps of the door, point 3 of the wall and point 4 of the door hinge. This is because the 4 points represent the material/partition of the room.

3. Discussion

Karaoke room is an interesting room to be visited by most people to unwind after work. People can sing as long as they want to. Some of them really have a good voice, while the some others just to express their feelings. Therefore, karaoke rooms are synonymous with noise. To examine the quantities of noise in karaoke rooms, we took some samples of karaoke rooms in Surabaya. In addition, we also performed measurements related to acoustic parameters, whether the karaoke room give attention to the acoustics aspects or not.

3.1. Background Noise (BN)

BN measurement aims to identify the noise criteria (NC) in karaoke room. Karaoke place surrounded by several sources of noise (traffic light, offices, restaurants and some markets). Based on the results of BN measurement in karaoke room obtained NC value for karaoke place A and B both small and large type room reached NC value of 40 -50. These values are equivalent to department stores, supermarkets, canteens, offices with business machines [9]. While the value of NC when as a music room should be 20 - 25. The high value of NC is caused by the room that has not been well insulated so that noise from outside easily spread in the room both from traffic light or others. However, NC impact is quite high because the karaoke room next to each other lead to noise to the other rooms.

microphon e

Sound source

Tascam

Notebook

Baloon Desk

Chair

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3.2. Noise Reduction (NR)

Based on the previous results, NC values are quite high, the main factor that causes is rooms are not isolated very well. Therefore, the next data retrieval is noise reduction measurement by measuring glass materials, door gap, walls, and door hinges. The data can be seen in Figure 2.3 below.

Figure 2.3. SPL chart inside and outside karaoke rooms

Figure 2.3 reveals the differences of SPL inside and outside lead to small values of NR. The lower NR values need an improvement of the building material of the karaoke room therefore the sounds of karaoke rooms do not interfere each other. Based on the data obtained, the SPL of karaoke rooms are quite high. Therefore, in this study also performed noise level measurement consisting of Leq, Lmax, and Lmin. The data obtained can be seen in Table 1 below.

Table 1. SPL of Karaoke Room A and B

Room Room A Room B

Leq Lmax Lmin Leq Lmax Lmin Inside 93.9 104.3 64.6 78.8 88.6 64.8 Outside 70.5 76.6 61.8 67.7 72.7 64.1

Table 1 shows Leq which is the equivalent continuous noise level, Lmax is the highest noise, and Lmin is the lowest noise level for karaoke rooms A and B. Leq noise value in karaoke rooms reaches 78.8 – 93.9. Where noise threshold value is 91-94 dB maximum listening for 1-2 hours [10]. The effects might occurred if we are exposed noise that exceeds the hearing threshold is hearing loss and also psychological effects [1][2].

55 65 75 85

SPL (dB)

60 70 80 90

SPL (dB)

60 70 80 90

SPL (dB)

55 65 75 85

63 125 250 500 1000 2000 4000 8000

SPL (dB)

Dalaminside Luaroutside

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3.3. Reverberation time (RT)

The reverberation time (RT) parameter is a very important parameter for identifying the acoustic quality of a space. Karaoke room can be categorised as a music room. Time analysis of RT is performed to evaluate RT values of karaoke rooms. RT measurement is performed at 6 measurement points where the distribution is quite representative of the room.

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Figure 2.4. Reverberation time plots of (a) karaoke room A (b) karaoke room B

The RT value obtained can be seen in Figure 2.5. At a frequency of 1000 Hz the value of RT in karaoke room A is 0.3 seconds to 0.4 seconds while the RT in karaoke room B is 0.2 seconds to 0.32 seconds. Therefore, the value of RT in karaoke room A is greater than karaoke room B at a frequency of 1000 Hz. This is due to the volume of karaoke room A is greater than the volume of karaoke room B [11]. The RT value obtained is quite low so that original sound does not interfere with reflected sound.

In addition, this study also analyze the clarity of sound, namely the C50 and C80 parameters.

3.3.1 C50

The room that is functioned for speech, has the criteria of clarity of speech, namely C50. This parameter is based on the comparison between the first 50 ms sound and the after one. The higher the C50 value, the better the clarity of the voice in the room. The comparison of C50 values on small type and large room type can be seen in Figure 2.5 below.

Figure 2.5. The comparison of C50 values on small type and large room type.

0 0.2 0.4 0.6 0.8 1

63 125 250 500 1000 2000 4000 8000

Reverberation time (s)

Frequency (Hz)

Titik 1 Titik 2 Titik 3 Titik 4 Titik 5 Titik 6

0 2 4 6 8 10 12 14

63 125 250 500 1000 2000 4000 8000

Reverberation time (s)

Frequency (Hz)

Titik 1 Titik 2 Titik 3

Titik 4 Titik 5 Titik 6

0 2 4 6 8 10

1 2 3 4 5 6

C50

Measurement points

Small room Large room

Point1 Point2

Point3 Point4 Point1

Point2

Point5 Point6

Point3 Point4 Point1

Point2

Point5 Point6

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According to the picture, it reveals that the value of C50 in the large room type is lower than the value of C50 in the small room type. This indicates that the level of clarity of the voice in the small room type is better than the large room type.

3.3.2 C80

The room that is purposed for music, has the criteria of clarity of sound of musical instruments namely C80. This parameter is based on the comparison between the first 80 ms sound and the after one. The following is the value of C80 in small room type and large room type. The higher the C80 value, the worse the clarity of the music in the room because of the sound of the music that is overlap. The comparison of C80 values on small type and large room type can be seen in Figure 2.6 below.

Figure 2.6. The comparison of C80 values on small type and large room type.

Based on Figure 2.6, C80 value in small room type is greater than large room type. This is related to the RT, the value of RT in the small room type is lower when compared to the large room type. The greater the value of C80, the initial or original sound received by the listener is not only the sound from the source but has been overlapped the reflected sound. Therefore, it can be true that the karaoke room has not been aware of the acoustic parameters, which is more intense in aspects of aesthetics and cleanliness of the room. Moreover, several karaoke rooms that are observed, both in small rooms and large rooms use same type of woofer speakers. The specifications used can be seen in Table 2, below.

Table 2. Speaker specification in karaoke rooms.

Specification Proel V12A BIK BJS-768

Type 2-way vented enclosure 2 way 3 speakers Bass-reflex type

Angular Coverage 90° H x 60° V 90° H x 60° V

Impedance 8 Ohm 8 Ohm

Frequency Response 50 Hz - 20 kHz 35 Hz - 20 kHz Sound Pressure Level Maksimal 124 dB 91 dB/W at 1m Dimensions (W x H x D) 380 x 600 x 328 mm 520 x 304 x 299 mm

Total peak power 600 Watts 500 Watts

Net Weigh 13 kg/ 1 pce 10,8 kg/ 1 pce

The selection of woofer-type speakers shows that karaoke owners want a dominant sound is in low frequencies (bass). This selection is because bass sounds are preferred when listening to music.

0 2 4 6 8 10 12 14

0 2 4 6 8

C80

point

Large room Small room

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4. Conclusion

According to the research results, it can be concluded as follows

• The NC values of karaoke room A and B are 45 and 50, respectively. These values have not satisfied the requirement of NC value for music room, i.e., 20 to 25.

• The reverberation time values of karaoke room A are 0.3 second to 0.4 second, while the room B are 0.2 second to 0.32 second at the frequency of 1000 Hz. Moreover, the reverberation time values of karaoke room A in low frequency (63 Hz to 125 Hz) are greater than karaoke room B.

This is because the absorption coefficient of material of partition of karaoke room B is less than karaoke room A in low frequency.

• The NR value of karaoke room A consist of glass 17 dBA, door gap 14 dBA, wall 18 dBA, door hinges 7 dBA at the frequency of 1000 Hz. Meanwhile, The NR value of karaoke room B consist of glass 12 dBA, door gap 8 dBA, wall 10 dBA, door hinges 9 dBA at the frequency of 1000 Hz. Furthermore, the NR values are still below the standard for glass, door gap, door hinges, and wall.

• The values of Leq in the karaoke A is 93.9 dBA and 70.5 dBA outside the room while the values of Leq in the karaoke B is 78.8 dBA and 67.7 dBA outside the room.

References

[1] M. Y. Park, “Assessment of potential noise-induced hearing loss with commercial ‘Karaoke’

noise,” Int. J. Ind. Ergon., vol. 31, no. 6, pp. 375–385, 2003, doi: 10.1016/S0169- 8141(03)00023-4.

[2] D. A. N. Inspection and P. T. Primatexco, “Kebisingan Dan Gangguan Psikologis Pekerja Weaving Loom Dan Inspection Pt. Primatexco Indonesia,” JHE (Journal Heal. Educ., vol. 2, no. 2, pp. 130–137, 2017, doi: 10.15294/jhe.v2i2.22618.

[3] J. D. Thacher et al., “High-resolution assessment of road traffic noise exposure in Denmark,”

Environ. Res., vol. 182, no. December 2019, p. 109051, 2020, doi:

10.1016/j.envres.2019.109051.

[4] X. Wen et al., “Impacts of traffic noise on roadside secondary schools in a prototype large Chinese city,” Appl. Acoust., vol. 151, pp. 153–163, 2019, doi:

10.1016/j.apacoust.2019.02.024.

[5] A. Gupta, “Karaoke : A Tool for Promoting Reading,” Read. Matrix An Int. Online J., vol. 6, no. August, pp. 80–89, 2006.

[6] R. Daido, M. Ito, S. Makino, and A. Ito, “Automatic evaluation of singing enthusiasm for karaoke,” Comput. Speech Lang., vol. 28, no. 2, pp. 501–517, 2014, doi:

10.1016/j.csl.2012.07.007.

[7] C. Guan, Y. Fu, X. Lu, E. Chen, X. Li, and H. Xiong, “Efficient karaoke song recommendation via multiple kernel learning approximation,” Neurocomputing, vol. 254, no. 2017, pp. 22–32, 2017, doi: 10.1016/j.neucom.2016.10.083.

[8] İ. H. Erten, “Using Karaoke in Language Classrooms: Exploring Potentials and Prospects,”

Procedia - Soc. Behav. Sci., vol. 199, pp. 589–596, 2015, doi: 10.1016/j.sbspro.2015.07.560.

[9] I. Sheet, “Noise_Rating,” vol. 44, no. 0, 2000, [Online]. Available: http://www.sfu.ca/sonic- studio/handbook/Noise_Rating.html.

[10] KEPMENKER, “KEPUTUSAN MENTERI TENAGA KERJA NOMOR : KEP-5l/tIEN/1999 TENTANG NILAI AMBANG BATAS FAKTOR FISIKA,” p. 10, 1999, [Online].

Available: https://jdih.kemnaker.go.id/data_wirata/1999-2-6.pdf.

[11] L. L. Beranek, “Acoustics_-_L._Beranek.pdf.” p. 491, 1954.