31-Oct-2023, 01:19
@Jean-Marie ,
The hearing protection standard/legal requirement is for a time weighted average level. The employer is required to keep the average level an employee to which the employee is exposed to an average of 85 dBA over an 8 hour period in Australia (the level is different in the US and may be different elsewhere also). The peak levels the employee may be exposed to during that period can be higher but the prescribed average level should not be exceeded.
Your peaks of 102 dBA are fine provided your average listening level is lower. How much lower is hard to say because there are 3 factors involved.
The first is how close the average level is to the peak level and the average level may not be in the middle of the dynamic range, it will be closer to the higher end of the range if there's a lot of loud passages and/or long periods of loud passages in the music, in which case you would need to keep your peaks lower in order to not exceed the average level in the standard. On the other hand if the music is generally soft with little in the way of loud passages, even louder peaks may be possible without exceeding the average level.
The second reason is where things start to get messy. While it sounds like the hearing protection standards are intended to prevent hearing damage, they're actually standards intended to ensure an employer takes "reasonable precautions" to protect the hearing of their employees. "Reasonable precautions" does not mean preventing all hearing damage whatsoever, it is accepted that some people will suffer hearing loss even if the standards are met. In some countries the standards are weighted more towards the employer's interests than others. It the US the standard is 88 dBA whereas here in Australia it's 85 dBA. In the US the standard provides less protection than it does in Australia and more employees will suffer hearing loss as a result but even in Australia with that 3 dB lower standard hearing loss can occur.
The third reason is whetre things get messier. The standard is an average over 8 hours because the length of the standard working day is 8 hours. Employers are responsible for the employee's noise exposure while they're working but not when the employee is not working. Office workers are exposed to noise levels significantly below the prescribed standard level while at work because offices tend to be much quieter spaces than industrial and construction sites so the 24 hour whole day exposure of an office worker tends to be lower than that of an industrial or construction worker. The problem is that our total daily exposure contributes to our risk of hearing damage, not just what get's measured over 8 hours, and hearing damage is progressive, it normally takes years for people to start to notice it and it's their total exposure over that longer period of years which eventually causes the problem that someone first notices. As far as I know no one has ever come up with a guide to a whole day safe exposure limit or for a guide to safe exposure to noise over a period of years. We've got a useful guideline but it's not a particularly precise guideline for short term exposure and we've got no way of measuring total exposure over the longer term during which damage occurs or what the effect of a consistent pattern of exposure over the medium to long term is compared to an intermittent pattern of exposure over the same period.
And all of the above only applies to music and other "continuous" sounds. It doesn't apply to very loud, very brief durations sounds like gunshots for example. That sort of sound produces a sudden, violent, air pressure variation which can be very damaging and even a single exposure to that sort of sound may cause hearing damage whereas loud music and other sounds normally only produce hearing damage over a much longer period.
Re your instrument player story: I haven't heard that but if there is some truth in it, the truth will be not that instrument players prefer to play at around 80 dBA levels but at levels at which they perceive the sound of their instrument to be around equal volume to an 80 dBA sound at 1000 Hz. Bass players, for example, have to produce higher sound pressure levels in order to balance the sound of their instruments against the sound of the mid-range instruments. I suspect that there is an element of truth to the story but in any musical ensemble not all players are playing equally loud, some are always playing louder than others and who is playing louder and who is playing softer depends on what's happening in the music at the time and how loud each musician has to play in order to produce a balanced sound in the space in which they're playing.The louder they have to play for the music the less difference in level there will be between the bass players and the mid-range players, for instance, because the ear's sensitivity to low frequencies increases as the SPL of the frequency increases. Look at a set of equal loudness curves and you will see the curves start to flatten out as the sound pressure level increases. Musicians compensate for that "automatically" because they're balancing the level of their instrument to that of the rest of the players by ear.
Don't forget that sound pressure level meters weren't even devised before the 20th century so musicians obviously didn't need them in order to "get things right" before meters became availalble and they haven't started using them for that purpose since meters became available. The relative loudness of individual musicians in a group has always been something the musicians work out by ear and I can't see that changing. Listeners could use a meter and work out some interesting things about the balance the musicians choose but musicians are always going to be guided by how the music sounds, not how the music measures, when they're making music.
Measurements are really useful but measurements can't tell us whether the music we're measuring sounds "good" or "right", our ears tell us that. Measurements can tell us when whatever it is we're hearing is loud enough to be a potential risk to the hearing of most people but it can't tell us whether it's an actual risk to our own hearing because that depends on a lot of things which we can't measure. It can give us some good guidelines but not a guarantee.
One of the things I had drummed into me during my studies was that "measurements tell you a lot about what you measure, they tell you nothing about what you don't measure". There's always something we aren't measuring. Measurements are always only a part of the story and they're not always the important part of the story.
Cheers to you too,
David
The hearing protection standard/legal requirement is for a time weighted average level. The employer is required to keep the average level an employee to which the employee is exposed to an average of 85 dBA over an 8 hour period in Australia (the level is different in the US and may be different elsewhere also). The peak levels the employee may be exposed to during that period can be higher but the prescribed average level should not be exceeded.
Your peaks of 102 dBA are fine provided your average listening level is lower. How much lower is hard to say because there are 3 factors involved.
The first is how close the average level is to the peak level and the average level may not be in the middle of the dynamic range, it will be closer to the higher end of the range if there's a lot of loud passages and/or long periods of loud passages in the music, in which case you would need to keep your peaks lower in order to not exceed the average level in the standard. On the other hand if the music is generally soft with little in the way of loud passages, even louder peaks may be possible without exceeding the average level.
The second reason is where things start to get messy. While it sounds like the hearing protection standards are intended to prevent hearing damage, they're actually standards intended to ensure an employer takes "reasonable precautions" to protect the hearing of their employees. "Reasonable precautions" does not mean preventing all hearing damage whatsoever, it is accepted that some people will suffer hearing loss even if the standards are met. In some countries the standards are weighted more towards the employer's interests than others. It the US the standard is 88 dBA whereas here in Australia it's 85 dBA. In the US the standard provides less protection than it does in Australia and more employees will suffer hearing loss as a result but even in Australia with that 3 dB lower standard hearing loss can occur.
The third reason is whetre things get messier. The standard is an average over 8 hours because the length of the standard working day is 8 hours. Employers are responsible for the employee's noise exposure while they're working but not when the employee is not working. Office workers are exposed to noise levels significantly below the prescribed standard level while at work because offices tend to be much quieter spaces than industrial and construction sites so the 24 hour whole day exposure of an office worker tends to be lower than that of an industrial or construction worker. The problem is that our total daily exposure contributes to our risk of hearing damage, not just what get's measured over 8 hours, and hearing damage is progressive, it normally takes years for people to start to notice it and it's their total exposure over that longer period of years which eventually causes the problem that someone first notices. As far as I know no one has ever come up with a guide to a whole day safe exposure limit or for a guide to safe exposure to noise over a period of years. We've got a useful guideline but it's not a particularly precise guideline for short term exposure and we've got no way of measuring total exposure over the longer term during which damage occurs or what the effect of a consistent pattern of exposure over the medium to long term is compared to an intermittent pattern of exposure over the same period.
And all of the above only applies to music and other "continuous" sounds. It doesn't apply to very loud, very brief durations sounds like gunshots for example. That sort of sound produces a sudden, violent, air pressure variation which can be very damaging and even a single exposure to that sort of sound may cause hearing damage whereas loud music and other sounds normally only produce hearing damage over a much longer period.
Re your instrument player story: I haven't heard that but if there is some truth in it, the truth will be not that instrument players prefer to play at around 80 dBA levels but at levels at which they perceive the sound of their instrument to be around equal volume to an 80 dBA sound at 1000 Hz. Bass players, for example, have to produce higher sound pressure levels in order to balance the sound of their instruments against the sound of the mid-range instruments. I suspect that there is an element of truth to the story but in any musical ensemble not all players are playing equally loud, some are always playing louder than others and who is playing louder and who is playing softer depends on what's happening in the music at the time and how loud each musician has to play in order to produce a balanced sound in the space in which they're playing.The louder they have to play for the music the less difference in level there will be between the bass players and the mid-range players, for instance, because the ear's sensitivity to low frequencies increases as the SPL of the frequency increases. Look at a set of equal loudness curves and you will see the curves start to flatten out as the sound pressure level increases. Musicians compensate for that "automatically" because they're balancing the level of their instrument to that of the rest of the players by ear.
Don't forget that sound pressure level meters weren't even devised before the 20th century so musicians obviously didn't need them in order to "get things right" before meters became availalble and they haven't started using them for that purpose since meters became available. The relative loudness of individual musicians in a group has always been something the musicians work out by ear and I can't see that changing. Listeners could use a meter and work out some interesting things about the balance the musicians choose but musicians are always going to be guided by how the music sounds, not how the music measures, when they're making music.
Measurements are really useful but measurements can't tell us whether the music we're measuring sounds "good" or "right", our ears tell us that. Measurements can tell us when whatever it is we're hearing is loud enough to be a potential risk to the hearing of most people but it can't tell us whether it's an actual risk to our own hearing because that depends on a lot of things which we can't measure. It can give us some good guidelines but not a guarantee.
One of the things I had drummed into me during my studies was that "measurements tell you a lot about what you measure, they tell you nothing about what you don't measure". There's always something we aren't measuring. Measurements are always only a part of the story and they're not always the important part of the story.
Cheers to you too,
David
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.
Brisbane, Qld, Australia
