Log in
Register
Home
Forums
New posts
Search forums
What's new
New posts
New profile posts
Latest activity
News
Members
Current visitors
New profile posts
Search profile posts
Features
Log in
Register
Search
Search titles only
By:
Search titles only
By:
New posts
Search forums
Menu
Install the app
Install
Reply to thread
Home
Forums
Pro Audio
Installs
SPL metering, logging, alarm
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Message
<blockquote data-quote="George Friedman-Jimenez" data-source="post: 98233" data-attributes="member: 1115"><p>Re: SPL metering, logging, alarm</p><p></p><p>The science of hearing protection has been pretty well worked out, if not widely accepted by the entertainment industry. OSHA has formulas for how much SPL can be tolerated without substantially increasing risk of hearing loss, legally enforceable but likely not fully protective. NIOSH has more conservative recommendations, supported by more and better science, but not accepted by industry in the regulatory standard negotiations. dBA is used because it is currently believed that higher frequencies do more damage to hearing than lower frequencies, given similar dB SPL. NIOSH has summarized the science here: </p><p><a href="http://www.cdc.gov/niosh/docs/98-126/pdfs/98-126.pdf" target="_blank">http://www.cdc.gov/niosh/docs/98-126/pdfs/98-126.pdf</a></p><p></p><p>While both these systems of recommendations were developed for workplace settings, they do not assume 8 hours of exposure and the formulas are flexible enough to incorporate much shorter periods of exposure to louder levels. All of those recommendations can actually incorporate both occupational and personal/recreational exposures to loud sound. For example, an hour and a half long dance class with SPL of 92 dBA slow at the ear of the dancer "uses up" the entire NIOSH noise dose quota for the entire day, ie assuming that person has zero additional exposure to loud noise over 85 dBA that day. Average SPL above that will increase risk of hearing loss, statistically across the population. People concerned about hearing loss should also pay attention to additional clues such as ringing in the ears or temporary mild hearing loss for hours or days after the exposure, and periodic hearing tests by a competent audiologist are recommended for all people who are exposed to loud sound near these levels. While there is certainly individual variabliity in who gets hearing loss and who doesn't, and we all know people who have great hearing and have been exposed to more than their fair share of loud sound, we do not have adequate science to predict who will and who won't get serious hearing loss later in life. Hearing loss is generally irreversible so once it happens, it is too late, so trying to follow the NIOSH recommendations seems prudent.</p><p></p><p>That said, I believe SPL is not the only important factor in this discussion. Having played congas for over 40 years on and off for dance classes in dance studios, mostly in NYC, I believe much of the problem is caused by the extreme reflectivity of the walls, floors and ceilings of most studios. Granted, it is even easier to overdo the SPL with a PA speaker than with a conga, but it is amazing how little actual acoustic power it takes to really move people to dance. Quality trumps quantity. In addition, the clarity of rhythmic parts of the music is important and this usually gets seriously smeared by the glass and sheet rock walls with hardwood floors.</p><p></p><p>In theory adding subs would add rhythmic SPL at frequencies not likely to cause hearing damage, however the acoustics of most dance studios would support strong resonant modes and give very uneven bass. Putting in effective bass traps and broad spectrum absorption and diffusors on the walls and ceiling could get expensive and would require a serious commitment of the owner. In my experience, however, the sound has been much better and more danceable with lower SPLs in the acoustically treated performance spaces I have played in than in untreated dance studios, especially when there is enough audience in the house to absorb a lot of the reflected highs.</p><p></p><p>Regarding measurement, the Acoustic Alarm unit Bennett recommended looks interesting, thanks Bennett. Another possible option for a logging SPL meter, calibrated but not legally approved for OSHA enforcement, is the Etymotic Research ER-200DW7 personal dosimeter. It looks like a nice inexpensive pocket sized unit that will answer the questions and produce the Leq and cumulative dose plots needed to approach the question the OP has raised. I have not tried it but am considering purchasing one. Has anyone used this?</p><p><a href="http://www.etymotic.com/hp/er200d.html" target="_blank">Etymotic Research, Inc. - ER?200DW7 Personal Noise Dosimeter with Data Logging</a></p><p><a href="http://www.etymotic.com/pdf/er200dw7_user_manual.pdf" target="_blank">http://www.etymotic.com/pdf/er200dw7_user_manual.pdf</a></p></blockquote><p></p>
[QUOTE="George Friedman-Jimenez, post: 98233, member: 1115"] Re: SPL metering, logging, alarm The science of hearing protection has been pretty well worked out, if not widely accepted by the entertainment industry. OSHA has formulas for how much SPL can be tolerated without substantially increasing risk of hearing loss, legally enforceable but likely not fully protective. NIOSH has more conservative recommendations, supported by more and better science, but not accepted by industry in the regulatory standard negotiations. dBA is used because it is currently believed that higher frequencies do more damage to hearing than lower frequencies, given similar dB SPL. NIOSH has summarized the science here: [URL]http://www.cdc.gov/niosh/docs/98-126/pdfs/98-126.pdf[/URL] While both these systems of recommendations were developed for workplace settings, they do not assume 8 hours of exposure and the formulas are flexible enough to incorporate much shorter periods of exposure to louder levels. All of those recommendations can actually incorporate both occupational and personal/recreational exposures to loud sound. For example, an hour and a half long dance class with SPL of 92 dBA slow at the ear of the dancer "uses up" the entire NIOSH noise dose quota for the entire day, ie assuming that person has zero additional exposure to loud noise over 85 dBA that day. Average SPL above that will increase risk of hearing loss, statistically across the population. People concerned about hearing loss should also pay attention to additional clues such as ringing in the ears or temporary mild hearing loss for hours or days after the exposure, and periodic hearing tests by a competent audiologist are recommended for all people who are exposed to loud sound near these levels. While there is certainly individual variabliity in who gets hearing loss and who doesn't, and we all know people who have great hearing and have been exposed to more than their fair share of loud sound, we do not have adequate science to predict who will and who won't get serious hearing loss later in life. Hearing loss is generally irreversible so once it happens, it is too late, so trying to follow the NIOSH recommendations seems prudent. That said, I believe SPL is not the only important factor in this discussion. Having played congas for over 40 years on and off for dance classes in dance studios, mostly in NYC, I believe much of the problem is caused by the extreme reflectivity of the walls, floors and ceilings of most studios. Granted, it is even easier to overdo the SPL with a PA speaker than with a conga, but it is amazing how little actual acoustic power it takes to really move people to dance. Quality trumps quantity. In addition, the clarity of rhythmic parts of the music is important and this usually gets seriously smeared by the glass and sheet rock walls with hardwood floors. In theory adding subs would add rhythmic SPL at frequencies not likely to cause hearing damage, however the acoustics of most dance studios would support strong resonant modes and give very uneven bass. Putting in effective bass traps and broad spectrum absorption and diffusors on the walls and ceiling could get expensive and would require a serious commitment of the owner. In my experience, however, the sound has been much better and more danceable with lower SPLs in the acoustically treated performance spaces I have played in than in untreated dance studios, especially when there is enough audience in the house to absorb a lot of the reflected highs. Regarding measurement, the Acoustic Alarm unit Bennett recommended looks interesting, thanks Bennett. Another possible option for a logging SPL meter, calibrated but not legally approved for OSHA enforcement, is the Etymotic Research ER-200DW7 personal dosimeter. It looks like a nice inexpensive pocket sized unit that will answer the questions and produce the Leq and cumulative dose plots needed to approach the question the OP has raised. I have not tried it but am considering purchasing one. Has anyone used this? [URL="http://www.etymotic.com/hp/er200d.html"]Etymotic Research, Inc. - ER?200DW7 Personal Noise Dosimeter with Data Logging[/URL] [URL]http://www.etymotic.com/pdf/er200dw7_user_manual.pdf[/URL] [/QUOTE]
Insert quotes…
Verification
Post reply
Home
Forums
Pro Audio
Installs
SPL metering, logging, alarm
Top
Bottom
Sign-up
or
log in
to join the discussion today!