can any one tell me about scan of body's viberation frequency

<drjamilurrahman@gmail.com> wrote in message
news:c1f078dc-bdef-4264-b004-6df4923d5ea4@d70g2000hsb.googlegroups.com...
> can any one tell me about scan of body's viberation frequency

Depends on the frequency and VOLTAGE of the line you are holding!!

And maybe SpellCheck could lead you somewhere.

<drjamilurrahman@gmail.com> wrote in message
news:c1f078dc-bdef-4264-b004-6df4923d5ea4@d70g2000hsb.googlegroups.com...
> can any one tell me about scan of body's viberation frequency

http://www.google.com/search?hl=en&q=vi ... human+body

On Thu, 7 Feb 2008 00:32:32 -0800 (PST), drjamilurrahman@gmail.com
wrote:

>can any one tell me about scan of body's viberation frequency

Just remember: Seven HURTS!

(7 Hertz is the approximate resonant frequency of the gut.
At high levels, it is reported to cause extreme discomfort and
nausea.)

Best regards,



Bob Masta

DAQARTA v3.50
Data AcQuisition And Real-Time Analysis
http://www.daqarta.com
Scope, Spectrum, Spectrogram, FREE Signal Generator
Science with your sound card!

"Bob Masta" <NoSpam@daqarta.com> wrote in message
news:47aaf9ac.910101@news.sysmatrix.net...
> On Thu, 7 Feb 2008 00:32:32 -0800 (PST), drjamilurrahman@gmail.com
> wrote:
>
>>can any one tell me about scan of body's viberation frequency
>
> Just remember: Seven HURTS!
>
> (7 Hertz is the approximate resonant frequency of the gut.
> At high levels, it is reported to cause extreme discomfort and
> nausea.)
>
> Best regards,
>
>
>
> Bob Masta

There was a MythBusters episode that dealt with this subject. I'm not sure
if they went down to 7Hz, but I think they did, and they did refer to the
so-called "brown noise". At the frequencies they did use, at (at
least)120dBspl (iirc), there were no ill effects.

On the other hand, SouthPark did a related episode, too. The results were
much different.

Bob

In article <IZ-dnaVal87fqzbanZ2dnUVZ_g2dnZ2d@giganews.com>, BobW wrote:
>
>"Bob Masta" <NoSpam@daqarta.com> wrote in message
>news:47aaf9ac.910101@news.sysmatrix.net...
>> On Thu, 7 Feb 2008 00:32:32 -0800 (PST), drjamilurrahman@gmail.com
>> wrote:
>>
>>>can any one tell me about scan of body's viberation frequency
>>
>> Just remember: Seven HURTS!
>>
>> (7 Hertz is the approximate resonant frequency of the gut.
>> At high levels, it is reported to cause extreme discomfort and
>> nausea.)
>>
>> Best regards,
>>
>> Bob Masta
>
>There was a MythBusters episode that dealt with this subject. I'm not sure
>if they went down to 7Hz, but I think they did, and they did refer to the
>so-called "brown noise". At the frequencies they did use, at (at
>least)120dBspl (iirc), there were no ill effects.
>
>On the other hand, SouthPark did a related episode, too. The results were
>much different.

Achieving 120 dB at 7 Hz is a tall order.

Consider what dort of loudspeakers are needed to achieve 120 dB at 30 or
50 Hz. Go ahead with an SPL meter, loudspeakers, sinewave oscillator, and
amplifier. Outdoors that gets to be a tall order much past point blank
range.

Ever see a local band or a DJ with really good really loud deep bass?
My experience is that the most impressive deep bass was from bass bins
whose frequency response was full blast only down to about 50 Hz.
Maintaining high loudspeaker efficiency to lower frequencies requires the
loudspeakers to be proportionately larger.

For example, one in "ideal half space" needs to have a volume around
..01% of a cubic wavelength of the lowest frequency at which it works well
to have efficiency only about 1-2% from that frequency on up. (Narrowband
designs can be smaller.) Efficiency increases roughly with volume, though
significantly begins to level off around 20% (at which point you can
maintain increase in "sensitivity" by having the loudspeaker large enough
to be directional).

.01% of a cubic wavelength is roughly a 6 foot cube at 7 Hz.

- Don Klipstein (don@misty.com)

"Don Klipstein" <don@manx.misty.com> wrote in message
news:slrnfqn5fu.l8t.don@manx.misty.com...
> In article <IZ-dnaVal87fqzbanZ2dnUVZ_g2dnZ2d@giganews.com>, BobW wrote:
>>
>>"Bob Masta" <NoSpam@daqarta.com> wrote in message
>>news:47aaf9ac.910101@news.sysmatrix.net...
>>> On Thu, 7 Feb 2008 00:32:32 -0800 (PST), drjamilurrahman@gmail.com
>>> wrote:
>>>
>>>>can any one tell me about scan of body's viberation frequency
>>>
>>> Just remember: Seven HURTS!
>>>
>>> (7 Hertz is the approximate resonant frequency of the gut.
>>> At high levels, it is reported to cause extreme discomfort and
>>> nausea.)
>>>
>>> Best regards,
>>>
>>> Bob Masta
>>
>>There was a MythBusters episode that dealt with this subject. I'm not sure
>>if they went down to 7Hz, but I think they did, and they did refer to the
>>so-called "brown noise". At the frequencies they did use, at (at
>>least)120dBspl (iirc), there were no ill effects.
>>
>>On the other hand, SouthPark did a related episode, too. The results were
>>much different.
>
> Achieving 120 dB at 7 Hz is a tall order.
>
> Consider what dort of loudspeakers are needed to achieve 120 dB at 30 or
> 50 Hz. Go ahead with an SPL meter, loudspeakers, sinewave oscillator, and
> amplifier. Outdoors that gets to be a tall order much past point blank
> range.
>
> Ever see a local band or a DJ with really good really loud deep bass?
> My experience is that the most impressive deep bass was from bass bins
> whose frequency response was full blast only down to about 50 Hz.
> Maintaining high loudspeaker efficiency to lower frequencies requires the
> loudspeakers to be proportionately larger.
>
> For example, one in "ideal half space" needs to have a volume around
> .01% of a cubic wavelength of the lowest frequency at which it works well
> to have efficiency only about 1-2% from that frequency on up. (Narrowband
> designs can be smaller.) Efficiency increases roughly with volume, though
> significantly begins to level off around 20% (at which point you can
> maintain increase in "sensitivity" by having the loudspeaker large enough
> to be directional).
>
> .01% of a cubic wavelength is roughly a 6 foot cube at 7 Hz.
>
> - Don Klipstein (don@misty.com)


Here are some of the details:

http://www.meyersound.com.au/brownnote.shtm

The test sessions were conducted in a large parking lot at Golden Gate
Fields racetrack, on the shores of San Francisco Bay. Savage stood in the
middle of the subwoofer ring, where he experienced the effect of very low
frequency sounds (down to 5 Hz) at extremely high levels (120 dB SPL with a
9 Hz sine wave, up to 153 dB peak with narrow-band noise), though the higher
levels were possible only above 20Hz. Safety was a prime consideration:
tests were limited to about five minutes in each frequency range, and
industrial-grade hearing protection was used above 120 dB. Savage was wired
to medical monitoring machinery and watched closely by paramedics during the
tests, while additional protection for those working in close proximity to
the subwoofer stack was provided by a box of extra-large Depends.

Bob

On Thu, 7 Feb 2008 22:25:06 -0800, "BobW"
<nimby_NEEDSPAM@roadrunner.com> wrote:

>
>"Don Klipstein" <don@manx.misty.com> wrote in message
>news:slrnfqn5fu.l8t.don@manx.misty.com...
>> In article <IZ-dnaVal87fqzbanZ2dnUVZ_g2dnZ2d@giganews.com>, BobW wrote:
>>>
>>>"Bob Masta" <NoSpam@daqarta.com> wrote in message
>>>news:47aaf9ac.910101@news.sysmatrix.net...
>>>> On Thu, 7 Feb 2008 00:32:32 -0800 (PST), drjamilurrahman@gmail.com
>>>> wrote:
>>>>
>>>>>can any one tell me about scan of body's viberation frequency
>>>>
>>>> Just remember: Seven HURTS!
>>>>
>>>> (7 Hertz is the approximate resonant frequency of the gut.
>>>> At high levels, it is reported to cause extreme discomfort and
>>>> nausea.)
>>>>
>>>> Best regards,
>>>>
>>>> Bob Masta
>>>
>>>There was a MythBusters episode that dealt with this subject. I'm not sure
>>>if they went down to 7Hz, but I think they did, and they did refer to the
>>>so-called "brown noise". At the frequencies they did use, at (at
>>>least)120dBspl (iirc), there were no ill effects.
>>>
>>>On the other hand, SouthPark did a related episode, too. The results were
>>>much different.
>>
>> Achieving 120 dB at 7 Hz is a tall order.
>>
>> Consider what dort of loudspeakers are needed to achieve 120 dB at 30 or
>> 50 Hz. Go ahead with an SPL meter, loudspeakers, sinewave oscillator, and
>> amplifier. Outdoors that gets to be a tall order much past point blank
>> range.
>>
>> Ever see a local band or a DJ with really good really loud deep bass?
>> My experience is that the most impressive deep bass was from bass bins
>> whose frequency response was full blast only down to about 50 Hz.
>> Maintaining high loudspeaker efficiency to lower frequencies requires the
>> loudspeakers to be proportionately larger.
>>
>> For example, one in "ideal half space" needs to have a volume around
>> .01% of a cubic wavelength of the lowest frequency at which it works well
>> to have efficiency only about 1-2% from that frequency on up. (Narrowband
>> designs can be smaller.) Efficiency increases roughly with volume, though
>> significantly begins to level off around 20% (at which point you can
>> maintain increase in "sensitivity" by having the loudspeaker large enough
>> to be directional).
>>
>> .01% of a cubic wavelength is roughly a 6 foot cube at 7 Hz.
>>
>> - Don Klipstein (don@misty.com)
>
>
>Here are some of the details:
>
>http://www.meyersound.com.au/brownnote.shtm
>
>The test sessions were conducted in a large parking lot at Golden Gate
>Fields racetrack, on the shores of San Francisco Bay. Savage stood in the
>middle of the subwoofer ring, where he experienced the effect of very low
>frequency sounds (down to 5 Hz) at extremely high levels (120 dB SPL with a
>9 Hz sine wave, up to 153 dB peak with narrow-band noise), though the higher
>levels were possible only above 20Hz. Safety was a prime consideration:
>tests were limited to about five minutes in each frequency range, and
>industrial-grade hearing protection was used above 120 dB. Savage was wired
>to medical monitoring machinery and watched closely by paramedics during the
>tests, while additional protection for those working in close proximity to
>the subwoofer stack was provided by a box of extra-large Depends.
>
>Bob
>

I seem to recall an early study on the 7 Hz phenomenon that
involved factory workers. When the sound was on (which of course
they couldn't "hear" directly at that low frequency), some workers
became ill. I got the impression that this was an ongoing exposure,
much longer than 5 minutes. Dont' recall anything about the sound
levels, or even if they tried to measure them throughout the factory.

I don't think they used speakers for this. It was pre-1960s so there
wouldn't have been much available anyway. I believe it was some sort
of steam whistle. (I have also seen mention of someone, early 1900s
I believe, who made a giant low-frequency steam whistle that allegedly
was so powerful it killed him "instantly" when he started it up.
YMMV <g>)

Best regards,




Bob Masta

DAQARTA v3.50
Data AcQuisition And Real-Time Analysis
http://www.daqarta.com
Scope, Spectrum, Spectrogram, FREE Signal Generator
Science with your sound card!

"Bob Masta" <NoSpam@daqarta.com> wrote in message
news:47ac46a4.1115650@news.sysmatrix.net...
> On Thu, 7 Feb 2008 22:25:06 -0800, "BobW"
> <nimby_NEEDSPAM@roadrunner.com> wrote:
>
>>
>>"Don Klipstein" <don@manx.misty.com> wrote in message
>>news:slrnfqn5fu.l8t.don@manx.misty.com...
>>> In article <IZ-dnaVal87fqzbanZ2dnUVZ_g2dnZ2d@giganews.com>, BobW wrote:
>>>>
>>>>"Bob Masta" <NoSpam@daqarta.com> wrote in message
>>>>news:47aaf9ac.910101@news.sysmatrix.net...
>>>>> On Thu, 7 Feb 2008 00:32:32 -0800 (PST), drjamilurrahman@gmail.com
>>>>> wrote:
>>>>>
>>>>>>can any one tell me about scan of body's viberation frequency
>>>>>
>>>>> Just remember: Seven HURTS!
>>>>>
>>>>> (7 Hertz is the approximate resonant frequency of the gut.
>>>>> At high levels, it is reported to cause extreme discomfort and
>>>>> nausea.)
>>>>>
>>>>> Best regards,
>>>>>
>>>>> Bob Masta
>>>>
>>>>There was a MythBusters episode that dealt with this subject. I'm not
>>>>sure
>>>>if they went down to 7Hz, but I think they did, and they did refer to
>>>>the
>>>>so-called "brown noise". At the frequencies they did use, at (at
>>>>least)120dBspl (iirc), there were no ill effects.
>>>>
>>>>On the other hand, SouthPark did a related episode, too. The results
>>>>were
>>>>much different.
>>>
>>> Achieving 120 dB at 7 Hz is a tall order.
>>>
>>> Consider what dort of loudspeakers are needed to achieve 120 dB at 30
>>> or
>>> 50 Hz. Go ahead with an SPL meter, loudspeakers, sinewave oscillator,
>>> and
>>> amplifier. Outdoors that gets to be a tall order much past point blank
>>> range.
>>>
>>> Ever see a local band or a DJ with really good really loud deep bass?
>>> My experience is that the most impressive deep bass was from bass bins
>>> whose frequency response was full blast only down to about 50 Hz.
>>> Maintaining high loudspeaker efficiency to lower frequencies requires
>>> the
>>> loudspeakers to be proportionately larger.
>>>
>>> For example, one in "ideal half space" needs to have a volume around
>>> .01% of a cubic wavelength of the lowest frequency at which it works
>>> well
>>> to have efficiency only about 1-2% from that frequency on up.
>>> (Narrowband
>>> designs can be smaller.) Efficiency increases roughly with volume,
>>> though
>>> significantly begins to level off around 20% (at which point you can
>>> maintain increase in "sensitivity" by having the loudspeaker large
>>> enough
>>> to be directional).
>>>
>>> .01% of a cubic wavelength is roughly a 6 foot cube at 7 Hz.
>>>
>>> - Don Klipstein (don@misty.com)
>>
>>
>>Here are some of the details:
>>
>>http://www.meyersound.com.au/brownnote.shtm
>>
>>The test sessions were conducted in a large parking lot at Golden Gate
>>Fields racetrack, on the shores of San Francisco Bay. Savage stood in the
>>middle of the subwoofer ring, where he experienced the effect of very low
>>frequency sounds (down to 5 Hz) at extremely high levels (120 dB SPL with
>>a
>>9 Hz sine wave, up to 153 dB peak with narrow-band noise), though the
>>higher
>>levels were possible only above 20Hz. Safety was a prime consideration:
>>tests were limited to about five minutes in each frequency range, and
>>industrial-grade hearing protection was used above 120 dB. Savage was
>>wired
>>to medical monitoring machinery and watched closely by paramedics during
>>the
>>tests, while additional protection for those working in close proximity to
>>the subwoofer stack was provided by a box of extra-large Depends.
>>
>>Bob
>>
>
> I seem to recall an early study on the 7 Hz phenomenon that
> involved factory workers. When the sound was on (which of course
> they couldn't "hear" directly at that low frequency), some workers
> became ill. I got the impression that this was an ongoing exposure,
> much longer than 5 minutes. Dont' recall anything about the sound
> levels, or even if they tried to measure them throughout the factory.
>
> I don't think they used speakers for this. It was pre-1960s so there
> wouldn't have been much available anyway. I believe it was some sort
> of steam whistle. (I have also seen mention of someone, early 1900s
> I believe, who made a giant low-frequency steam whistle that allegedly
> was so powerful it killed him "instantly" when he started it up.
> YMMV <g>)
>
> Best regards,
>
> Bob Masta
>

I gotta build me one of them steam whistles!

Bob

ShamShoon wrote:
> Can somebody help me understand the circuit in http://www.edn.com/artic=
le/CA6531584.html
> an NE555 based voltage to frequency converter. I tried simulating the
> circuit in LTSpice but couldn't get the NE555 to work.

I don't think it works, either.

> The article says that first the capacitor will be charging with an
> applied negative input voltage. So far so good. When the output
> reaches a certain voltage the discharge transistor Q1 will turn on and
> reduce the output voltage.
>=20
> This is what I don't get. If the voltage is decreasing on the cap
> after Q1 is turned on, we have now 3 currents at the negative input
> junction of the OpAmp.

The voltage on pin 2 of the opamp is a virtual ground, very=20
nearly zero volts. The discharge transistor can draw no=20
current from that node.

> 1) Q1 current going upside down
> 2) Input voltage current going from right to left through the
> resistors P1,R1 (0 to a negative voltage)
> 3) Cap discharge current going from left to right (The only way I can
> think of if the output voltage is decreasing).
>=20
> So now we have at one junction, 3 positive currents going away from
> the junction, which by KCL is impossible.
>=20
> So what am I missing ??

An editor?

This line is completely wrong:
"As the voltage on C1 reaches two-thirds of VCC, the 555=92s=20
internal discharge transistor opens, and the voltage on C1=20
returns to one-third the voltage of VCC, the lower=20
comparator threshold." Q1 turns on after the threshold=20
voltage exceeds 2/3rds of the supply voltage, not turns off.

But it doesn't matter, since there is no source of positive=20
current into the opamp inverting input, top run the miller=20
capacitor negatively. You would need a positive current=20
source switched on and off by Q1 (on when Q1 pulled low) to=20
make this work. I think they lost a PNP transistor in=20
translation.

--=20
Regards,

John Popelish

On Mar 2, 2:49 pm, John Popelish <jpopel...@rica.net> wrote:
[snip]
>
> I don't think it works, either.
>
[snip]

Thanks John. Now I got some of my sanity back. I think the editors
should have done some verification before including it.

On Sun, 2 Mar 2008 13:31:28 -0800 (PST), ShamShoon <mhs000@gmail.com>
wrote:

>Can somebody help me understand the circuit in http://www.edn.com/article/CA6531584.html
>an NE555 based voltage to frequency converter. I tried simulating the
>circuit in LTSpice but couldn't get the NE555 to work.
>
>The article says that first the capacitor will be charging with an
>applied negative input voltage. So far so good. When the output
>reaches a certain voltage the discharge transistor Q1 will turn on and
>reduce the output voltage.
>
>This is what I don't get. If the voltage is decreasing on the cap
>after Q1 is turned on, we have now 3 currents at the negative input
>junction of the OpAmp.
>
>1) Q1 current going upside down
>2) Input voltage current going from right to left through the
>resistors P1,R1 (0 to a negative voltage)
>3) Cap discharge current going from left to right (The only way I can
>think of if the output voltage is decreasing).
>
>So now we have at one junction, 3 positive currents going away from
>the junction, which by KCL is impossible.
>
>So what am I missing ??
>
>Thank you.

Most of the EDN submitted circuits are crap. They're just filler, to
keep the "editorial" content up enough so they can ship ads at the
cheap "magazine" postal rate. They're all journalism types; what would
they know about electronics?

John

"ShamShoon" <mhs000@gmail.com> wrote in message
news:2abd0182-cb33-4cf8-8435-65d0a9119b53@s8g2000prg.googlegroups.com...
> Can somebody help me understand the circuit in
> http://www.edn.com/article/CA6531584.html
> an NE555 based voltage to frequency converter. I tried simulating the
> circuit in LTSpice but couldn't get the NE555 to work.
>
> The article says that first the capacitor will be charging with an
> applied negative input voltage. So far so good. When the output
> reaches a certain voltage the discharge transistor Q1 will turn on and
> reduce the output voltage.
>
> This is what I don't get. If the voltage is decreasing on the cap
> after Q1 is turned on, we have now 3 currents at the negative input
> junction of the OpAmp.
>
> 1) Q1 current going upside down
> 2) Input voltage current going from right to left through the
> resistors P1,R1 (0 to a negative voltage)
> 3) Cap discharge current going from left to right (The only way I can
> think of if the output voltage is decreasing).
>
> So now we have at one junction, 3 positive currents going away from
> the junction, which by KCL is impossible.
>
> So what am I missing ??
>
> Thank you.


There seems to be an error in the schematic posted. Pin 7 should probably be
connected to the trigger/threshold node, not to the input of the opamp. I'm
guessing that they want to discharge the integrator cap when it gets to 2/3
of Vcc.

Regards,
Bob Monsen

"M. Hamed" <mhs000@gmail.com> wrote in message
news:15c2694f-a4d7-4c78-9b1b-89ece1a72b81@s37g2000prg.googlegroups.com...
> On Mar 2, 2:49 pm, John Popelish <jpopel...@rica.net> wrote:
> [snip]
>>
>> I don't think it works, either.
>>
> [snip]
>
> Thanks John. Now I got some of my sanity back. I think the editors
> should have done some verification before including it.

The editors did their job. I didn't spot a single misspelled word.

Bob