1. Using a controlled environment a room enclosed with 12 mm Tile (Particle Board or MDF) a normal Conversation 60 to 65 dB, was reduced to a 32dB this reduction makes the conversation not understandable. As for the people working on cutting aluminum it has been determined that Sound is in the range of 110 dB therefore the use of earplugs is mandatory to prevent earing loss. Here are some interesting numbers, collected from a variety of sources, that help one to understand the volume levels of various sources and how they can affect our hearing.

5. Imperceptible Change Barely Perceptible Change Clearly Noticeable Change About Twice as Loud About Four Times as Loud 1dB 3dB 5dB 10dB 20dB

6. Normal piano practice Fortissimo Singer, 3' Chamber music, small auditorium Piano Fortissimo Violin Cello Oboe Flute Piccolo Clarinet French horn Trombone Tympani & bass drum Walkman on 5/10 Symphonic music peak Amplifier, rock, 4-6' Rock music peak 60 -70dB3dB 70dB 75 - 85dB 84 - 103dB 82 - 92dB 85 -111dB 95-112dB 92 -103dB 90 -106dB 85 - 114dB 90 - 106dB 85 - 114dB 106dB 94dB 120 - 137dB 120dB 150dB

4. Hours per day 8 6 4 3 2 1.5 1 .5 .25 or less 0 Sound level 85dBA 86dBA 88dBA 89dBA 90dBA 92dBA 94dBA 97dBA 100dBA 112dBA

3. Hours per day 8 6 4 3 2 1.5 1 .5 .25 or less Sound level 90dB 92dB 95dB 97dB 100dB 102dB 105dB 110dB 115dB

7. • One-third of the total power of a 75-piece orchestra comes from the bass drum. • High frequency sounds of 2-4,000 Hz are the most damaging. The uppermost octave of the piccolo is 2,048-4,096 Hz. • Aging causes gradual hearing loss, mostly in the high frequencies. • Speech reception is not seriously impaired until there is about 30 dB loss; by that time severe damage may have occurred. •Hyp ertension and various psychological difficulties can be related to noise exposure. • The incidence of hearing loss in classical musicians has been estimated at 4-43%, in rock musicians 13- 30%. • Recent NIOSH studies of sound levels from weapons fires have shown that they may range from a low of 144 dB SPL for small caliber weapons such as a 0.22 caliber rifle to as high as a 172 dB SPL for a 0.357 caliber revolver. Double ear protection is recommended for shooters, combining soft, insertable ear plugs and external ear muffs. Statistics for the Decibel (Loudness) Comparison Chart were taken from a study by Marshall Chasin , M.Sc., Aud(C), FAAA, Centre for Human Performance & Health, Ontario, Canada. There were some conflicting readings and, in many cases, authors did not specify at what distance the readings were taken or what the musician was actually playing. In general, when there were several readings, the higher one was chosen.

2. Weakest sound heard Whisper Quiet Library at 6' Normal conversation at 3' Telephone dial tone City Traffic (inside car) Train whistle at 500', Truck Traffic Jackhammer at 50' Subway train at 200' Level at which sustained exposure may result in hearing loss Hand Drill Power mower at 3' Snowmobile, Motorcycle Power saw at 3' Sandblasting, Loud Rock Concert Pain begins Pneumatic riveter at 4' Even short term exposure can cause permanent damage - Loudest recommended exposure WITH hearing protection Jet engine at 100' 12 Gauge Shotgun Blast Death of hearing tissue Loudest sound possible Weakest sound heard Whisper Quiet Library at 6' Normal conversation at 3' Telephone dial tone City Traffic (inside car) Train whistle at 500', Truck Traffic Jackhammer at 50' Subway train at 200' Level at which sustained exposure may result in hearing loss Hand Drill Power mower at 3' Snowmobile, Motorcycle Power saw at 3' Sandblasting, Loud Rock Concert Pain begins Pneumatic riveter at 4' Even short term exposure can cause permanent damage - Loudest recommended exposure WITH hearing protection Jet engine at 100' 12 Gauge Shotgun Blast Death of hearing tissue Loudest sound possible 0dB 30dB 60-65dB 80dB 85dB 90dB 95dB 95dB 90 - 95dB 98dB 107dB 100dB 110dB 115dB 125dB 125dB 140dB 140dB 165dB 180dB 194dB

8. The National Institute for Occupational Safety and Health (NIOSH) -http://www.cdc.gov/niosh/topics/noise/ American Tinnitus Association – Information and help for those with tinnitus Hear Tomorrow – The Hearing Conservation Workshop H.E.A.R. – Hearing Education and Awareness for Rockers American Tinnitus Association – for musicians and music lovers Turn It to the Left – from the American Academy of Audiology Listen to Your Buds – from the American Speech-Language-Hearing Association Binge Listening: Is exposure to leisure noise causing hearing loss in young Australians? [pdf] – report from Australian Hearing, National Acoustic Laboratories Hearing Aids and Music: Interview with Marshall Chasin, AuD – from the American Academy of Audiology Safe Listening Resources – from the National Hearing Conservation Association OSHA Noise and Hearing Conservation -