Noise exposure in movie theaters: a preliminary study of sound levels during the showing of 25 films.
The harmful effects of noise exposure during leisure-time activities are beginning to receive some scrutiny. We conducted a preliminary study to investigate the noise levels during the showings of 25 different films. During each screening, various sound measurements were made with a dosimeter. The movies were classified on the basis of both their Motion Picture Association of America (MPAA) rating and their genre, and the size of the theater and the size of the audience were taken into consideration in the final analysis. Our findings suggest that the sound levels of many movies might be harmful to hearing, although we can draw no definitive conclusions. We did not discern any relationship between noise levels and either MPAA rating or genre. Further studies are recommended.
Noise exposure associated with the workplace has been linked to hearing loss for many years. In response, the United States government's Occupational Safety and Health Administration (OSHA) issued regulations to limit occupational exposure to noise. Attention is now being directed to the effects of noise exposure during leisure-time activities. Various studies have shown that sound levels at concerts and nightclubs and those emitted by personal listening devices can be hazardous. (1-3) Also, seemingly innocuous hazards may be more ubiquitous than previously thought; for example, entertainment options for children such as toys and arcade games have been found to emit potentially harmful levels of noise. (4,5)
With the exception of a preliminary study reported by the senior author (R.T.S.) and colleagues in 1998, (6) no investigation of the sound levels in movie theaters has been conducted. In view of recent technological advances in sound effects, the question of whether movie theater noise reaches hazardous levels warrants reexamination. In this article, we describe another preliminary study of this subject.
Materials and methods
For this study, 25 movies were randomly selected for viewing. Over a period of 1 month, one of the authors (A.W.) watched each of these movies in a multiplex that housed a number of theaters of the same size and design. During the showings, noise levels were measured with a Quest NoisePro DLX noise logging dosimeter (Coll Health and Safety; Mississaugua, Ont.). All measurements were made with A-weighting (dBA), slow averaging, and a 5-dB exchange rate. Five different sound measurements were made:
* the maximum sound level for each film;
* the peak level (Lpk)--that is, the highest instantaneous sound level that the microphone detected;
* a dose reading where a value of 100% is the maximum allowable exposure to accumulated continuous noise (according to OSHA, a 100% dose occurs for an average sound level of 90 dBA over an 8-hour period);
* the average sound level (Lavg);
* the sound exposure level (SEL); assuming the sampled run time to be greater than 1 second, the SEL is the equivalent 1-second noise that would be equal in energy to the noise that was sampled over the test period.
The manufacturer of the dosimeter cautions that the Lpk reading is independent of the slow/fast response for which the unit is set, so it should be read with caution because the machinery's wiring can greatly increase the levels of the most quiet of sounds. The data were analyzed by QuestSuite Professional II software (Quest Technologies; Oconomowoc, Wis.).
The movies were classified on the basis of both their Motion Picture Association of America (MPAA) rating and their genre (table 1). The size of each individual movie theater and the size of the audience during each screening were also measured to ensure that the acoustic environments were similar when viewing films of different ratings and genres.
Our study's primary aim was to determine whether a movie-goer is exposed to noise levels that could be harmful to hearing. A secondary goal was to determine whether a specific MPAA rating or genre is predictive of sound levels.
There were no significant differences in the size, shape, and capacity of the individual theaters, and during the screenings, there were no significant differences in audience size.
Sound levels. The three highest maximum sound levels were recorded during the showings of Transformers (133.9 dBA), License to Wed (129.1 dBA), and The Simpsons Movie (128.6 dBA). The lowest levels were recorded during Evening (105.4 dBA), You Kill Me (109.0 dBA), and I Know Who Killed Me (109.4 dBA) (table 2).
The highest Lavg readings were recorded during Rush Hour 3 (80.2 dBA), Who's Your Caddy? (78.3 dBA), and Hairspray (78.3 dBA). The lowest levels were recorded during Evening, You Kill Me, and No Reservations--52.0, 52.1, and 55.9 dBA, respectively (table 2). The most prominent differences between these two groups of movies were that the latter featured much more conversation and the few high-intensity noises that did occur were of short duration. The high-Lavg films featured near-constant background music.
Overall SEL readings were highest for Hairspray, Rush Hour 3, and Transformers, with levels of 142.4,142.1, and 141.5 dBA, respectively (table 2). Of these three films, only Hairspray was a surprising finding; its place at the top of this list was probably attributable to the presence of nearly continuous background music.
The two movies with the least amount of time during which SEL readings reached or exceeded 90 dBA were You Kill Me (13 min cumulative) and Evening (20 min). Neither motion picture ever registered a noise level of 110 dBA, and even levels at or above 100 dbA were fairly scarce--2 minutes for You Kill Me and 7.5 seconds for Evening (table 3).
MPAA rating. Of the 25 films, 15 were rated PG- 13, 5 were rated R, 4 were rated PG, and 1 was rated G (table 1). The relative paucity of G, PG, and R movies in this study made it difficult to make valid comparisons on the basis of MPAA rating, so these data should be interpreted with caution. But overall, we did not find any association between rating and sound level.
The mean SEL was 131.5 dBA for the G/PG films, 131.8 dBA for the PG- 13 films, and 126.6 dBA for the R-rated films. The SELs of the 5 G/PG movies (Becoming lane, Hairspray, No Reservations, Ratatouille, and Underdog) raise concerns about the sound levels in movies geared toward families and children, and we believe that this warrants further investigation.
We found a somewhat similar trend when we determined mean Lavg levels according to MPAA rating: 68.1 dBA for the G/PG films, 69.6 dBA for the PG-13 films, and 62.9 dBA for the R films.
Genre. Our data show that a film's genre was not predictive of noise levels. Of course, it is plausible that sound levels for a specific film would vary across different movie theaters. Confounding factors might include the age of the theater and the type, quality, and size of the sound equipment, as well as other factors.
It is important to identify which recreational activities pose a hearing hazard so that we can determine their relative importance and raise public awareness of them. Chung et al reported a troubling survey finding that a majority of adolescents and young adults had experienced impaired hearing or tinnitus after exposure to loud music at concerts or in clubs. (7) Unfortunately, only a few of them (8%) considered hearing loss to be a significant problem. Fortunately, most of the respondents said that they would be motivated to use ear protection if they were aware of the potential for permanent hearing loss (66% of respondents) or if such protection were advised by a medical professional (59%). Another survey found that an informational campaign that highlighted the risks associated with loud music could change young people's attitudes about noise. (8)
The movie theater is one of the most popular entertainment venues for families. Movie-goers obviously feel that the overall experience of watching a motion picture in a theater is worth the cost. Many would argue that the acoustics and sound effects are an important part of that experience; the sound effects of movies seen in theaters are difficult to replicate at home.
It has been suggested that children and adults should not be exposed at all to levels of 120 and 140 dB, respectively. Although these limits are controversial and have not been confirmed by any incontrovertible evidence, they can be used as reasonable guidelines. And our data certainly show that children who attend movies are likely to be exposed to levels well above 120 dB. Transformers, a film geared toward a younger audience, was the movie in which sound levels exceeded 90 dBA for the longest amount of time (126 min), and it was the only movie in which the maximum level exceeded 130 dBA.
Based on our analysis of exposure times and sound levels, it appears conceivable that movie-going might contribute to hearing loss, depending on the frequency and duration of exposures. For example, OSHA recommends that exposure to 115 dBA be limited to no more than 15 minutes. While no such degree of exposure occurred in this study, maximum sound levels reached or exceeded 110 dBA in 22 of the 25 movies we studied.
If it can be confirmed that movies do indeed pose a hearing hazard, changes are called for, and education and the promotion of precautions similar to those considered for rock concerts and other noisy activities may be appropriate. Changes in movie industry sound practices might also be appropriate.
This study was not designed to prove whether exposure to movie noise is either damaging or safe. Rather, it was a preliminary study to determine whether noise exposure is of sufficient magnitude to suggest a need for further investigation. We believe that it is, and we believe that prospective studies that include audiometry are warranted in order to more accurately identify the role of these sound exposures in either temporary or permanent changes in hearing thresholds.
(1.) Cohen A, Anticaglia J, Jones H. Sociocusis--hearing loss from non" occupational noise exposure. Sound &Vibration 1970;4(11):12-20.
(2.) Clark WW. Noise exposure from leisure activities: A review. J Acoust Soc Am 1991;90(1):175-81.
(3.) Mostafapour SP, Lahargoue K, Gates GA. Noise-induced hearing loss in young adults: The role of personal listening devices and other sources of leisure noise. Laryngoscope 1998;108(12):1832-9.
(4.) Yaremchuk K, Dickson L, Burk K, Shivapuja BG. Noise level analysis of commercially available toys. Int J Pediatr Otorhinolaryngol 1997; 41(2):187-97.
(5.) Plakke BL. Noise levels of electronic arcade games: A potential hearing hazard to children. Ear Hear 1983;4(4):202-3.
(6.) Sataloff RT, Rau G, Preston L. Noise exposure in movie theaters. Journal of Occupational Hearing Loss 1998;1(4):281-2.
(7.) Chung JH, Des Roches CM, Meunier J, Eavey RD. Evaluation of noise-induced hearing loss in young people using a web-based survey technique. Pediatrics 2005; 115 (4) :861-7.
(8.) Widen SE, Holmes AE, Erlandsson SI. Reported hearing protection use in young adults from Sweden and the USA: Effects of attitude and gender. Intl J Audiol 2006;45(5):273-80.
Anna Warszawa, MD; Robert T. Sataloff, MD, DMA, FACS
From the Department of Otolaryngology-Head and Neck Surgery, Drexel University College of Medicine, Philadelphia.
Corresponding author: Robert T. Sataloff, MD, DMA, Department of Otolaryngology-Head and Neck Surgery, Drexel University College of Medicine, 1721 Pine St., Philadelphia, PA 19103. E-mail: RTSataloff@PhillyENT.com
Table 1. MPAA * rating and genre for the 25 films studied MPAA Title rating Genre Becoming Jane PG Biography, drama, romance El Cantante R Biography, musical, drama Evening PG-13 Drama Hairspray PG Musical, drama, comedy Harry Potter and PG-13 Family, drama, fantasy, adventure the Order of the Phoenix Hot Rod PG-13 Action, adventure, teen drama I Know Who Killed Me R Drama, thriller I Now Pronounce You PG-13 Comedy Chuck and Larry Knocked Up R Comedy, romance, drama Last Legion PG-13 Action, adventure, war drama License to Wed PG-13 Comedy, romance Live Free or Die Hard PG-13 Action, adventure, thriller, crime No Reservations PG Comedy, romance, drama Ratatouille G Animated family comedy Rescue Dawn PG-13 Action, adventure, war drama Rush Hour 3 PG-13 Action, adventure, comedy Skinwalkers PG-13 Action, adventure, horror, suspense thriller Stardust PG-13 Adventure, sci-fi thriller, fantasy, drama Sunshine R Adventure, sci-fi mystery, crime The Bourne PG-13 Action, adventure, mystery Ultimatum thriller, drama, suspense The Simpsons Movie PG-13 Animated comedy Transformers PG-13 Action, adventure, sci-fi thriller Underdog PG Action, adventure, sci-fi, family comedy Who's Your Caddy? PG-13 Sports comedy You Kill Me R Comedy, thriller, crime * MPAA = Motion Picture Association of America. Table 2. Measured sound levels Max Lpk Dose Lavg SEL Title (dBA) (dBA) (%) (dBA) (dBA) Becoming Jane 127.7 139.2 0.578 63.0 126.8 El Cantante 115.1 117.2 3.716 76.0 140.3 Evening 105.4 109.0 0.008 52.0 96.4 Hairspray 128.0 143.2 5.011 78.3 142.4 Harry Potter and the 115.8 130.7 1.001 65.7 130.8 Order of the Phoenix Hot Rod 113.7 127.5 1.036 69.1 131.1 I Know Who Killed Me 109.4 125.5 0.254 57.6 120.9 1 Now Pronounce You 127.0 143.5 3.419 75.4 139.7 Chuck and Larry Knocked Up 123.8 137.4 0.382 59.0 123.9 Last Legion 116.8 120.3 3.946 77.8 140.7 License to Wed 129.1 141.5 0.767 66.5 128.9 Live Free or Die Hard 118.5 133.0 2.520 72.4 137.5 No Reservations 121.7 133.4 0.200 55.9 119.2 Ratatouille 125.0 143.7 1.620 70.4 134.3 Rescue Dawn 113.4 121.6 1.258 67.5 132.5 Rush Hour 3 118.8 117.0 4.784 80.2 142.1 Skinwalkers 118.3 141.5 1.646 72.0 134.4 Stardust 113.1 124.5 2.874 73.5 138.4 Sunshine 115.5 117.0 1.420 69.8 133.3 The Bourne Ultimatum 110.0 128.9 0.434 60.8 124.8 The Simpsons Movie 128.6 142.5 0.100 56.2 118.1 Transformers 133.9 144.7 4.414 75.9 141.5 Underdog 110.5 127.4 1.744 73.0 134.8 Who's Your Caddy? 128.2 144.3 3.720 78.3 140.3 You Kill Me 109.0 126.3 0.107 52.1 114.7 Key: Max = the maximum sound level; Lpk = the peak sound level that the microphone detected; Dose = dose reading where a value of 100% is the maximum allowable exposure to accumulated continuous noise; Lavg = average sound level; SEL = sound exposure level. Table 3. Cumulative amount of time movie-goers were exposed to different sound exposure levels Title [greater than or [greater than or equal to] 90 dBA equal to] 100d-BA Measured in minutes unless otherwise noted Becoming Jane 40 6 El Cantante 69 32 Evening 20 7.5 sec Hairspray 108 55 Harry Potter and the 55 13 Order of the Phoenix Hot Rod 53 12 I Know Who Killed Me 29 4 I Now Pronounce You 110 38 Chuck and Larry Knocked Up 75 7 Last Legion 74 32 License to Wed 53 7 Live Free or Die Hard 90 26 No Reservations 22 11 sec Ratatouille 73 16 Rescue Dawn 46 14 Rush Hour 3 78 42 Skinwalkers 62 21 Stardust 68 29 Sunshine 61 17 The Bourne Ultimatum 42 5 The Simpsons Movie 31 2 Transformers 126 50 Underdog 69 23 Who's Your Caddy? 81 36 You Kill Me 13 2 Title [greater than or [greater than or equal to] 110 dBA equal to] 120 dBA Measured in minutes unless otherwise noted Becoming Jane 7 sec 2.5 sec El Cantante 2 <1 sec Evening -- -- Hairspray 33 sec 8 sec Harry Potter and the 3 sec -- Order of the Phoenix Hot Rod 6.5 sec -- I Know Who Killed Me -- -- I Now Pronounce You 45 sec 2 sec Chuck and Larry Knocked Up 4 1 Last Legion 4 -- License to Wed <1 sec -- Live Free or Die Hard 50 sec -- No Reservations 4 sec -- Ratatouille 49 sec 7 sec Rescue Dawn 21 sec -- Rush Hour 3 3 -- Skinwalkers 1 -- Stardust 40 sec -- Sunshine 19 sec -- The Bourne Ultimatum 4 sec -- The Simpsons Movie 3 sec <1 sec Transformers 18 sec 9 sec Underdog 1 sec -- Who's Your Caddy? 1 2 sec You Kill Me -- -- Title [greater than or equal to] 130 dBA Measured in minutes unless otherwise noted Becoming Jane -- El Cantante -- Evening -- Hairspray -- Harry Potter and the -- Order of the Phoenix Hot Rod -- I Know Who Killed Me -- I Now Pronounce You -- Chuck and Larry Knocked Up -- Last Legion -- License to Wed -- Live Free or Die Hard -- No Reservations -- Ratatouille -- Rescue Dawn -- Rush Hour 3 -- Skinwalkers -- Stardust -- Sunshine -- The Bourne Ultimatum -- The Simpsons Movie -- Transformers 1 sec Underdog -- Who's Your Caddy? -- You Kill Me --
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||ORIGINAL ARTICLE|
|Comment:||Noise exposure in movie theaters: a preliminary study of sound levels during the showing of 25 films.(ORIGINAL ARTICLE)|
|Author:||Warszawa, Anna; Sataloff, Robert T.|
|Publication:||Ear, Nose and Throat Journal|
|Date:||Sep 1, 2010|
|Previous Article:||Extensive external auditory canal cholesteatoma in the infratemporal area without mastoid involvement: use of a new surgical technique.|
|Next Article:||Botulinum toxin-assisted endoscopic repair of traumatic vocal fold avulsion.|