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Re: [ST] db's and ears (was "Offroad exhaust" tune?)



First let me comment on audibility. While the mathematical relationships in the statement below are correct, a 3 db difference is certainly discernable to the human ear. Suttle, yes, but very discernable. A 10 db difference is significant. Very significant...at 30 or 40 or 50, its the difference between a whisper and a normally spoken voice. Somewhere above 100, 10 db is the diffference between just plain loud and the threshold of pain...
   
  Woovis, to answer your question directly:
   
  The plugs with 10 db less attenuation will let twice as much sound through...twice the helmet speaker volume, but also twice the wind noise, and in my opinion it will accomplish nothing. What you may try as a cheap and easy solution is a pair of earplugs with selective attenuation, where they attenuate differently at different frequencies. Try www.directsafety.com. Good folks, good products, and although you have to buy in bulk, they will send you a sampler of a few different earplugs if you ask them nice. ( While you are there, check out their safety glasses). They are shatter proof, stylish, have LARGE bend radiuses, and are cheap enough to be disposable....I get a few pairs in various shades, nest them together in my tank bag, and after they have been dropped a few times, I just pitch them and grab a new pair). Anyway, they should have some earplugs you will find interesting. Thats the cheap and dirty solution.
   
  The correct solution to this problem, I believe, does not yet exist to my knowledge, at least not in its entirety. The problem that we face as motorcyclists is wind noise. Lots of it. Enough to cause hearing damage on its own. So we where earplugs to combat that. Now we cant hear shit. We need to turn our helmet speakers up so loud the helmet rattles.. not really a solution either. I believe the solution to the problem is two fold: 1) Earbud speakers built into form fitting earplugs that specifically fit YOUR ear. These do exist, there were at least two companies selling them at the show, and   2) a setup with an interaural microphone, which I have not yet found.
   
  The form fitting earplugs are noteworthy for their sealing qualities. While I have not used them myself ( I am lucky enough to get a satisfactory seal from the cheapie earplugs, and, in spite of what I do for a living, or perhaps because of it, I have not yet had the desire to add audio or intercomm to my motorcycling) , there is hard evidence as to the quality of their seal, etc, etc. Depending on the compound used, you can select the desired db of attenuation. But what is more significant about these is that they separate the desired sound from the undesired....the transducer is mounted within these plugs, and is in front of the seal, while the wind is behind the seal and its noise kept out. Additionally, since you now dont have to overcome the wind noise, and have a VERY small sealed airspace to compress, your power requirements are much less, your output volume is much less, and unless you insist on listening to head banging acid rock at insane levels while you ride, yo
 ur
 hearing will last longer. The gain in quality is quite substantial. Clarity and dialogue intelligability are way , way better with this style of earpiece. Frequency response and fidelity are much better for music as well. MUCH BETTER, as in real, tight, controlled bass response, accurate image and tonal balance, etc, if that sort of thing matters to you. Its all about getting the sound you want up above the noise floor of the sound you dont want. Helmet speakers just crank up the volume to get above the already high noise floor of the wind. With earplugs in, you now have attenuated everything, but at different levels, and inconsistently so. What you really lose is the suttle, quiet stuff. These earpieces crush the noise floor, allowing the ability to hear suttle things over the transducer, be it inflection in the voice of the person you are talking to, or the little voices in the background on "Dark Side of the Moon"...and all of this at lower perceived volume to the listene
 r, which
 goes a long way toward preventing fatigue on those long rides, and long term hearing loss...While I dont yet own a pair, I have played around with them quite a bit, and they work real well. The $300 pair price tag is what has kept me away, that and the concious decision to not have music or the squawking SO intrude on my ride.....
   
  That is the larger half of the equation. Doable, and very effective for a price. And your Chu Moy amp will increase the sound quality that much more...
   
  The other half of the equation, one which I have yet to find a solution for , is on the microphone end if you are using intercomm. What you really need is an interaural microphone. Ask any of the people that make these intercomm/music products, though, and they have no clue what you are talking about. Attempt to explain it to them, and they look at you like you are from another planet ( 'course I am used to that anyway..). An interaural mic would also be placed on the inside of your earplug. It gathers your voice from within the earcanal, also isolated from wind noise. They do exist, however, I have yet to see one in use in one of these type products. If somone would make this, it would be the solution. You would have serious , contained sound quality, and you would have voice activated intercomm, without windnoise at either end.....I have not yet found this solution. Perhaps it is available if you mixed and matched some different headsets and things.
   
  The best example I can give you on noise floor is this : compare a CD to a recording of that same CD on a cassette tape ( remember those ). Particularly if you are listening to a piece of music with many quiet passages, like some classical pieces. If you get to a quiet passage, you will find yourself struggling to hear the music over the noise floor of the tape hiss. This is not a problem during the louder passages of the music. The noise floor is relativley constant. What you want is the desired sounds sufficiently above that noise floor. As with the CD, at the same volume, you can hear those quieter passages clearer, because the noise floor is sufficently lower, practically non existent. 
   
  Okay, I will apologise now to the rest of you for the off-topic technobabble...I can visualize eyes glazing over and such. Ping me or call me if you need more...
   
  John Ulizzi
  216-486-9371

Bil Swartz <bil@xxxxxxxxxx> wrote:
  On Thu, 9 Feb 2006, Sprint ST wrote:

> For example, in communications there have been tests that show a 3db 
> increase in sound levels could not be detected by the human ear. It 
> took a 10db increase to be detected reliably. 3db is double the power 
> output and 10db is 10 times the power.

Hey Rod,

I'm hoping that the example you mention above means you know a bit about 
that subject as I've been debating what to do about bike comms to make 
things more usable.

After going thru many prodcuts I've found Motocomm headsets and an 
FRS/GMRS radio make for a nice system for under $100/ea. We still have a 
hard time hearing when we're at speed though (65+) so was looking toward 
amplifying things. Tried the boostaroo and a small CMoy/MINT type amp 
that help a little but not quite enough.

We usually wear earplugs, such as Leight (sp?) Laser-Lites. I tried an 
alternative plug one day, one of the firmer bell shaped numbers which 
seemed to let more sound through.

So the question is, with the Laser-Lites claiming about a 33db reduction 
(I think it is), would a plug that claims a 23db reduction let more of the 
helmet speaker through and make a difference?

Thanks for anythying you can tell me. I'm going to see if I can find a 
plug like the Laser-Lites in construct but with a lower db reduction to 
test with.

-- 

._O_. '03 Sprint ST
-Bil- /_\o/_\ '98 Thunderbird Sport /~\
"No I don't want a pickle..." /H\ '98 VFR800FI -hers ASCII \ / Against
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