Should You Wear Hearing Protection with the Top Down? An Answer!
The deafness would just give me an excuse to be loud in restaurants and stuff and annoy people. 
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Joined: Feb 2004
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From: SF Bay Area
This is really a great thread, thanks for doing this! I always wear foam ear plugs when taking an extended or freeway drive with the top down. (I keep a package of plugs in the center console.) Even with the -15 db plugs in, its still pretty loud on the freeway. Its nice to know that I'm probably "safe" with the plugs.
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Joined: Aug 2003
Posts: 3,660
Likes: 2
From: Midlothian
This is all very accurate and appreciated - I have done these studies using my FFT spectrum analyzer.
Not sure why you used "A" weighting rather than "C", but it is of little consequence.
There are several things I would like to add:
1) Think of this post when you you are cranking 2-12" subs @ 30 Hz @ 100dB SPL for sustained periods in your "opther ride" or at home.
2) Sustained low frequency noise raises blood pressure - one theory is that humans respond to low frequency noises, esp patterned ones, as heavy footfalls, which could have represented a predator dangerous to us along the evolutionary trail. Likewise, it is no coincidence that our ears are about 6" apart, representing 1/2 wavelength of a 1kHz tone, which is the approximate range of a twig cracking - useful when stalking game, or not becoming game! Plus, since the ears are 180 degress apart, the sensitivity in this range also allows us to use the time/phase differentials between the sound hitting left ear/right ear to determine with amazing accuracy WHERE the sound is coming from. So we hear a twig from the left, and either turn quickly to attack the game, or duck the attack of a sabre-tooth tiger or another hominid.
3) I wear hearing protection in all vehicles on long trips - enclosed sedans can be worse than convertibles, because of the cavitation effects which can make normal resonances spike high, and the sound system often louder because there is space to use large drivers, and people EQ the high frequencies with "spitty" tweeters, which are more dangerous to our hearing long term.
4) BTW, if you hear ringing in your ears, the frequency of the ringing is often the frequency which is getting to the danger area - many permamanet hearing losses are measured to be at the same frequency as permanent ringing.
5) I have been meaning to measure the frequency amplitude linearity of the S2000's sound system: engine off, at idle with top up, idle with top down. My TL measured quite flat in the midrange, with the inevitable overly boosted bass which almost always has to be dieled in since the ambient low freqiency noise fo tires and drivetrain are loud, and would otherwise ?mask" the bass. But consider this: they may sum and null at certain points depending on the phase of the frequiency on the stereo vs. the phase of the car's noise, but where they sum, the amplitude can be dangerously loud, if sustained for long periods, as thr OSHA tables show.
Great thread! Thx!
Not sure why you used "A" weighting rather than "C", but it is of little consequence.
There are several things I would like to add:
1) Think of this post when you you are cranking 2-12" subs @ 30 Hz @ 100dB SPL for sustained periods in your "opther ride" or at home.
2) Sustained low frequency noise raises blood pressure - one theory is that humans respond to low frequency noises, esp patterned ones, as heavy footfalls, which could have represented a predator dangerous to us along the evolutionary trail. Likewise, it is no coincidence that our ears are about 6" apart, representing 1/2 wavelength of a 1kHz tone, which is the approximate range of a twig cracking - useful when stalking game, or not becoming game! Plus, since the ears are 180 degress apart, the sensitivity in this range also allows us to use the time/phase differentials between the sound hitting left ear/right ear to determine with amazing accuracy WHERE the sound is coming from. So we hear a twig from the left, and either turn quickly to attack the game, or duck the attack of a sabre-tooth tiger or another hominid.
3) I wear hearing protection in all vehicles on long trips - enclosed sedans can be worse than convertibles, because of the cavitation effects which can make normal resonances spike high, and the sound system often louder because there is space to use large drivers, and people EQ the high frequencies with "spitty" tweeters, which are more dangerous to our hearing long term.
4) BTW, if you hear ringing in your ears, the frequency of the ringing is often the frequency which is getting to the danger area - many permamanet hearing losses are measured to be at the same frequency as permanent ringing.
5) I have been meaning to measure the frequency amplitude linearity of the S2000's sound system: engine off, at idle with top up, idle with top down. My TL measured quite flat in the midrange, with the inevitable overly boosted bass which almost always has to be dieled in since the ambient low freqiency noise fo tires and drivetrain are loud, and would otherwise ?mask" the bass. But consider this: they may sum and null at certain points depending on the phase of the frequiency on the stereo vs. the phase of the car's noise, but where they sum, the amplitude can be dangerously loud, if sustained for long periods, as thr OSHA tables show.
Great thread! Thx!
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Joined: Mar 2004
Posts: 9
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From: Sarasota
This is a very interesting thread.
This is my first convertible and I've noticed that with the top down the noise really begins to annoy me especially while trying to listen to the radio but also gets tiring in general. I'm constantly having to crank the volume up and down in proportion to my speed.
I'v started to use my iPod with "in ear" buds and this makes my driving MUCH more enjoyable. I make sure not to keep the volume excessivly loud so as not to totally drown out the surroundings.
I know this is probably illegal but isn't this the same if not better than being enclosed in a "sound deadened " luxery vehicle with the tunes turned up a bit?
Am I being totally irresponsible?
This is my first convertible and I've noticed that with the top down the noise really begins to annoy me especially while trying to listen to the radio but also gets tiring in general. I'm constantly having to crank the volume up and down in proportion to my speed.
I'v started to use my iPod with "in ear" buds and this makes my driving MUCH more enjoyable. I make sure not to keep the volume excessivly loud so as not to totally drown out the surroundings.
I know this is probably illegal but isn't this the same if not better than being enclosed in a "sound deadened " luxery vehicle with the tunes turned up a bit?
Am I being totally irresponsible?