Re: Jacob's Ladder "Snap" (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Tue, 16 Dec 2003 12:10:27 -0700
From: Gomez <gomez@xxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Jacob's Ladder "Snap" (fwd)

On Monday, December 15, 2003, at 07:40  PM, High Voltage list wrote:

> Original poster: Steven Roys <sroys@xxxxxxxx>
>
> ---------- Forwarded message ----------
> Date: Mon, 15 Dec 2003 09:32:13 -0800
> From: Jim Lux <jimlux@xxxxxxxxxxxxx>
> To: High Voltage list <hvlist@xxxxxxxxxx>
> Subject: Re: Jacob's Ladder "Snap" (fwd)
>
> At 09:40 AM 12/15/2003 -0700, you wrote:
>> Original poster: Steven Roys <sroys@xxxxxxxx>
>>
>> ---------- Forwarded message ----------
>> Date: Fri, 12 Dec 2003 10:56:35 -0800 (PST)
>> From: Chris Roberts <quezacotl_14000000000000@xxxxxxxxx>
>> To: High Voltage list <hvlist@xxxxxxxxxx>
>> Subject: Jacob's Ladder "Snap"
>>
>>
>> Hi Everybody,
>>
>> I was recently talking to one of my neighbors about the "strange
>> lightning
>> thing" that I play around with, and he told me of hearing a story
>> about
>> how a Jacob's ladder can hurt your hearing. He said that when the arc
>> starts at the bottom, the "snap" heard is extremely loud, but so
>> quick of
>> a pulse that you don't register it as being as loud as it is. He
>> didn't
>> know whether or not it was true, and it sounded like a techno-myth to
>> me,
>> but has anyone else heard (pun intended) about this?
>
> Yes, it's possible to a have a very short impulse noise that doesn't
> sound
> loud, but actually is. Yes, one could damage one's hearing if one was
> subjected to enough of them.

This runs contrary to what OSHA says about hearing & exposure.
Can you cite a reference, or is this your opinion?

> If you're going to be working around loud noises much, invest the $200
> in a
> decent set of level limiting hearing protectors from, for instance,
> Peltor.   They have microphones that pass the sound through at full
> volume
> (or amplified, quite handy for hearing that evil corona hiss), but
> clamp it
> to a safe level.  Very, very nice for working with things that go
> suddenly
> "bang".

How do you know they are fast enough?  What's wrong with simple hearing
protectors?

> By the way, if you work with something that generates high level
> acoustic
> impulses repetitively (i.e. big Marx, etc.), you should be aware of the
> fact that there are effects other than those on your hearing.  I
> worked on
> a device that produced periodic loud explosions for theatrical use (to
> replace conventional "maroons" using powder).  After running some
> tests all
> day (several thousand shots), my hearing was fine (gotta love the
> Peltors),
> but my whole body ached.  Turns out the shock waves cause microlesions:
> essentially like getting beat on.  These were fairly big shots (many
> tens
> of kilojoules each.. easy with chemical energy)

I've experienced this around pyro.  A lot depends on the sharpness of
the report.
Spending all day around big BP cannons didn't do it, despite hundreds
of shots.
Spending a few hours around a few dozen chlorate salutes did it.  Of
course, I
was wearing hearing protection, and experienced no tinnitus that day or
the next
(tinnitus is a sure sign of hearing damage, but the absence of ringing
in the
ears must _not_ to be used as an indicator of safety)

  - Gomez