ronc said:
Actually, listening to music loud is not a good way to damage hearing. It needs to be above the pain threshold to be doing damage.
Close proximity to loud impact sounds is a really good way to ruin your hearing. High pitched shrieking from a router burning its way through a piece of plywood is also good.
It's not even the ear drum that gets damaged, but parts of the inner ear, like the cochlea.
Robh3606 said:
Time to find a new one. Umm John can you hear me??
Rob
WHAT???...speak up!
The ENT is standing there in the examination room with a stunned look on his face, hold the audiologist test result:
"What do you do(for a living)??"
I have suffered considerable hearing loss due to a complete disregard for it when I was younger.
He said that music would need to be loud and sustained, near the pain threshold to cause permanent damage, and that it would be broadband, and NOT the damage I have. The damage I have is the result of REALLY loud impact sounds (like using a sledge hammer to move a wall section in place with your ear close the plywood sheathing).
The kind of sounds that leave a ringing in your ears, no pain since the duration is too short.
ear pain
Well, there are good docs and there are the rest.... many of the ENT's I work with are rather narrowly focused individuals, heck most of the Docs <<over 120 of them, are clueless about the rest of the world outside of their little bubble of perceived expertise... (from someone who knows)
So, as this IS a DIY forum, the consensus seems to be...
What's the point of speakers that can produce 110+dB or so continuous (not peak) in a home listening environment with little compression if all that one accomplishes is damage to your hearing...? Many systems (mine included) can produce 105dB + sustained at the listening position with little if any compression and/or (linear or non-linear) distortion... with excellent perceived imaging from well recorded sources. The inference that higher level capable systems are better doesn't seem to be relevant.
John L.
Well, there are good docs and there are the rest.... many of the ENT's I work with are rather narrowly focused individuals, heck most of the Docs <<over 120 of them, are clueless about the rest of the world outside of their little bubble of perceived expertise... (from someone who knows)
So, as this IS a DIY forum, the consensus seems to be...
What's the point of speakers that can produce 110+dB or so continuous (not peak) in a home listening environment with little compression if all that one accomplishes is damage to your hearing...? Many systems (mine included) can produce 105dB + sustained at the listening position with little if any compression and/or (linear or non-linear) distortion... with excellent perceived imaging from well recorded sources. The inference that higher level capable systems are better doesn't seem to be relevant.
John L.
My wife is Department Chair in Audiology at Eastern Michigan University. I know this issue very well.
110 dB(C) (note no one has mentioned the weighting used, which is critical) is not damaging if it is music for less than an hour or so. Many commercial movie theaters are at this level for easily two hours - you don't walk out deaf (although I have had ringing which is a problem). And as far as listening at 110 dB(C), I do it quite often, but perhaps not regularly, so its not as extreme as you would like to think. And I'll say this, I have only ever witnessed a handful of speakers that don't sound terrible at this level - and they don't have dome tweeters.
You have to note how rapidly the level goes up with a desire for increased loudness. Subjects will usually rate 6 dB as an increment of "louder". So if 90 dB(C) is soft, then 96 dB(c) is medium, 102 dB(c) medium loud, 108 dB(c) is loud and 114 dB(c) is very loud. Note that going from soft to very loud is 24 dB or more than ten times the voltage levels. Soft to loud is still almost ten times the voltage and its perceived as only a three increment increase in loudness. Loudness and level ARE NOT the same thing.
And please, when talking about levels from an audio pespective, DON'T use weighting unless its "C". A and B weighting are totally inappropriate at these levels and for determining output requirements for audio systems.
As noted - table saws, routers, lawn mowers all of the things of daily life are far far more damaging than music at 110 dB(C). I never work with power tools without hearing protection - I care about my hearing, but I will listen to music at 110 dB(C) anytime that I feel like it and not worry in the least.
110 dB(C) (note no one has mentioned the weighting used, which is critical) is not damaging if it is music for less than an hour or so. Many commercial movie theaters are at this level for easily two hours - you don't walk out deaf (although I have had ringing which is a problem). And as far as listening at 110 dB(C), I do it quite often, but perhaps not regularly, so its not as extreme as you would like to think. And I'll say this, I have only ever witnessed a handful of speakers that don't sound terrible at this level - and they don't have dome tweeters.
You have to note how rapidly the level goes up with a desire for increased loudness. Subjects will usually rate 6 dB as an increment of "louder". So if 90 dB(C) is soft, then 96 dB(c) is medium, 102 dB(c) medium loud, 108 dB(c) is loud and 114 dB(c) is very loud. Note that going from soft to very loud is 24 dB or more than ten times the voltage levels. Soft to loud is still almost ten times the voltage and its perceived as only a three increment increase in loudness. Loudness and level ARE NOT the same thing.
And please, when talking about levels from an audio pespective, DON'T use weighting unless its "C". A and B weighting are totally inappropriate at these levels and for determining output requirements for audio systems.
As noted - table saws, routers, lawn mowers all of the things of daily life are far far more damaging than music at 110 dB(C). I never work with power tools without hearing protection - I care about my hearing, but I will listen to music at 110 dB(C) anytime that I feel like it and not worry in the least.
Rybaudio said:
I normally mean 1 meter if I don't say something else. Sure spl at listening position is what counts.. but one should remember that many sounds are coming from both tweeters and also the room gain (reflections and "reverberation") add some even in the high registers.
A 100W rated resistor (Arcol HS100) of 0.1ohm between amp and voicecoil. The current (voltage over the resistor) logged continuously by a digital o-scope. Checked the difference in the beginning and end of the trace.
/Peter
graaf said:
I'm guessing that they were using dB(A). This could easily explain this level of difference, but there is also a subjective aspect to "loud". I never use dB(A) even though virtually all of the data that you read is A weighted. Speakers aren't designed to A weighting, they are not flat when "A" weighted, but they should be flat in "C" weighting, which is why I use it and the only way to talk about level requirements etc. If I measure a playback level at 110 dB(C) with a broadband signal then I need to be able to produce 110 dB at that position with a pure tone (some will argue that this is not correct, but there is a counter argument that it is).
If that distance is at say 4 m then this is 122 dB(C) at 1 meter. Thats how I got the numbers that I quote as a target. The system needs to do this, without significant compression, to meet my objectives, which as I have shown, are NOT unreasonable, even if they are rather high for an apartment. I have listened in my room at these levels with the kids asleep upstairs.
gedlee said:
thanks for response Dr Geddes
how could this 90 dB(A) be translated to dB(C)?
Have you any idea why did they use this (A)weighting?
gedlee said:
aren’t those "inverse square" equations for free field conditions?
What about closed, reverberant and rather acoustically small spaces like our (typical) apartments?
gedlee said:
I am sure that Your objectives are not unreasonable!
best,
graaf
graaf said:how could this 90 dB(A) be translated to dB(C)?
Have you any idea why did they use this (A)weighting?
aren’t those "inverse square" equations for free field conditions?
What about closed, reverberant and rather acoustically small spaces like our (typical) apartments?
I am sure that Your objectives are not unreasonable!
best,
graaf
Can't translate DB(A) into "C" without knowing the spectrum. They probably used "A" for all the reasons that people have used it for years, but not realizing that its application doesn't really apply here. If they did use "C" as they should have, then I can't explain the differences.
Yes, in a real room you are quite correct that the situation is more complex. I do free field calcs, for the ease of doing them to get ballpark numbers. Thats all we are talking about here are ball park numbers.
If you study the problem you will find that you really do have to take the jump to a compression driver to go from "medium loudness" to "very loud". This is 12 dB more voltage and that is not easily absorbed by a small voice coil. BY my criteria, "medium loud" is about all you can get without a compression driver. And thats not to mention the directivity control. You could get the directivity control with a small tweeter on a waveguide, but having done that the waveguides work a lot better with a compression driver and there is all that extra headroom to ones advantage.
220, 221, whatever it takes
In my role as safety officer many many moons ago for larger corporations, I'm keenly aware of occupational exposure limits. I agree there isn't a 1:1 correlation between noise exposure and music exposure, but the general principals still apply. (as in, if it hurts my ears, and I measure 110dB(C) peaks, to fracture an old saw "If it hurts too much to be false, it must be true"..
I always measure "C" weighted. My Denon AVR calibrates (through Audyssey) my system to 105dB(C) reference at my 15' listening distance, a number I have verified using independent microphones and equipment. Since I have quasi linesource mains, my levels fall off ~1/R rather than 1/R^2, which I have also verified by measurements, this in a roughly 15,000 ft^3 2 story cathedral ceiling space. Makes quite a difference in the listening experience. Besides the 6' BG 75's the setup includes 2 Advent 6002's as rear surrounds, 2x12" sonosubs, 1 tuned to maximally flat to Fb and the second as extended bass shelf (good to ~16 Hz -3dB or so). Given the total bass driver complement of 4x 6 1/2" midbass in the lines, 2 x 10" bass in the surrounds, and the 2x 12" sonosubs strategically located at mode nulls along the side walls, I reach 105dB(C) quite readily w/o compression or distortion at most frequencies (~102dB(C) @ 20Hz), and that's about as LOUD as I ever want to hear anything for any significant time frame.
Of course as always, ymmv.
John L.
In my role as safety officer many many moons ago for larger corporations, I'm keenly aware of occupational exposure limits. I agree there isn't a 1:1 correlation between noise exposure and music exposure, but the general principals still apply. (as in, if it hurts my ears, and I measure 110dB(C) peaks, to fracture an old saw "If it hurts too much to be false, it must be true"..
I always measure "C" weighted. My Denon AVR calibrates (through Audyssey) my system to 105dB(C) reference at my 15' listening distance, a number I have verified using independent microphones and equipment. Since I have quasi linesource mains, my levels fall off ~1/R rather than 1/R^2, which I have also verified by measurements, this in a roughly 15,000 ft^3 2 story cathedral ceiling space. Makes quite a difference in the listening experience. Besides the 6' BG 75's the setup includes 2 Advent 6002's as rear surrounds, 2x12" sonosubs, 1 tuned to maximally flat to Fb and the second as extended bass shelf (good to ~16 Hz -3dB or so). Given the total bass driver complement of 4x 6 1/2" midbass in the lines, 2 x 10" bass in the surrounds, and the 2x 12" sonosubs strategically located at mode nulls along the side walls, I reach 105dB(C) quite readily w/o compression or distortion at most frequencies (~102dB(C) @ 20Hz), and that's about as LOUD as I ever want to hear anything for any significant time frame.
Of course as always, ymmv.
John L.
gedlee said:
I have found it - it is "from 50Hz to 10kHz"
http://www.soundstagemagazine.com/measurements/test_loudspeakers.htm
can You translate now this please
best,
graaf
graaf said:
I have found it - it is "from 50Hz to 10kHz"
http://www.soundstagemagazine.com/measurements/test_loudspeakers.htm
can You translate now this please
best,
graaf
No, its still not possible. I have to know the spectrum of the signal that was played, not just the bandwidth. But I'm warning you, even if you find the spectrum, its more calculation than I'm willing to do.
gedlee said:
May I explore this a bit? I too hear something unpleasant in the sound of dome tweeters when very (but not outrageously) loud. Recent experience with a couple of compression drivers suggests that they do not have the same trait - whatever it is.
I'm beginning to doubt whether thermal compression can be the culprit. An 810921 tweeter sounded like others I had tried. While looking for compression, it broke about 50K above ambient - just 2dB compression. I was incautious, as I expected to be able to run up to 100K or more before damaging the tweeter. So the experiment came to an abrupt end. The band limited noise used was white and had little power below 2kHz, so I was not expecting mechanical failure.
I did not destroy the tweeter in over a year of listening, with a lower crossover (and spectrum biased to lower frequency), but it failed at the time it was compressing by just 2dB. So I expect that I usually had less compression even when listening to loud music. That does not seem very much. So what else could make the "dome tweeter" sound? (Not that I intend to use dome tweeters, but I remain curious.)
Extreme distortion at displacement limits? (10s of %)
Flux modulation causing severe distortion?
Mechanical problems with the dome?
Ken
gedlee said:
ok! I understand!
I've read more carefully what the NRC people wrote.
Could it be that the measurement at 90 dB at 2m done in the anechoic chamber is not weighted at all?
After all it is THD+N measurement
I suppose that it is done with sine wave sweep (from 50 to 10 kHz)
Is the SPL measurement weighted in such circumstances?
And they say that the purpose of the measurement is:
"Measures THD+N output at discrete frequency intervals for above-normal listening levels"
"above normal listening levels"?
geeez... I am completely confused
graaf said:
And they say that the purpose of the measurement is:
"Measures THD+N output at discrete frequency intervals for above-normal listening levels"
"above normal listening levels"?
geeez... I am completely confused
Do remember to distinguish the mean level of a swept sine wave from a loud section in music. It is easy to see that 90 dB at 2m could be above a mean "normal" level yet far below a peak that you might want your speakers to reproduce painlessly from time to time. After all, what is normal?
Ken