[ChrisCoaster]

I know that A-weighting approximates human sensitivity and C-weighting
is "flat".

But which one is "pink" and which is "white"??

For once and for all set me straight on the terminology.

-CC

[Dave C]

"ChrisCoaster" wrote in message
...
I know that A-weighting approximates human sensitivity and C-weighting
is "flat".

But which one is "pink" and which is "white"??

For once and for all set me straight on the terminology.

-CC

Pink noise is "shaped" to achieve equal power / octave. White is "flat"
resulting in increasing power / octave.

Dave

[William Sommerwerck]

"ChrisCoaster" wrote in message
...

I know that A-weighting approximates human sensitivity
and C-weighting is "flat".
But which one is "pink" and which is "white"?
For once and for all set me straight on the terminology.

You are confused, and the answers already posted are, in varying degrees,
incomplete/incorrect.

The weighting curves -- A and C -- have nothing to do with color. As you
say, C is basically flat, while A approximates the sensitivity of the human
ear at low levels.

"White" and "pink" refer to the noise test signals. White noise has equal
energy per bandwidth. For example, the 8ve between 1000 and 2000Hz has four
times the bandwidth and thus four times the energy as the 8ve between 250
and 500Hz. Thus, the energy rises at 3dB per 8ve. This is not what we think
of as "flat", though there is nothing "wrong" about white noise. That's just
the way it is.

Pink noise is white noise that's been run through a "pinking" filter with a
3dB/8ve rolloff. It has equal energy per octave. On an analyzer with 8ve or
third-8ve filters, the analyzer displays a "flat" response to pink noise.
This makes it easier to interpret the display, because it fits the way we
think about response.

[Scott Dorsey]

ChrisCoaster wrote:
I know that A-weighting approximates human sensitivity and C-weighting
is "flat".

Not really. C-weighting is very far from flat.

But which one is "pink" and which is "white"??

Neither one. The "pink" and "white" curves are used for noise sources,
the A-weighting and C-weighting for measuring devices. They are unrelated
curves and not used for the same things.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Richard Webb[_3_]]

On Tue 2011-Jul-05 09:38, Scott Dorsey writes:

But which one is "pink" and which is "white"??

Neither one. The "pink" and "white" curves are used for noise
sources, the A-weighting and C-weighting for measuring devices.
They are unrelated curves and not used for the same things.

INdeed. WOuld you care to expound on when one might use a
weighted and when C weighted, since that would be his next
question, and would probably be beneficial. IN fact, if we
were still updating the faq that might be a good addition.


Regards,
Richard
--
| Remove .my.foot for email
| via Waldo's Place USA Fidonet-Internet Gateway Site
| Standard disclaimer: The views of this user are strictly his own.

[William Sommerwerck]

Would you care to expound on when one might use a
weighted and when C weighted, since that would be his next
question, and would probably be beneficial? In fact, if we
were still updating the FAQ that might be a good addition.

As I and others said, the A weighting mimics the response of the ear at low
levels. That should be self-explanatory.

[Richard Webb[_3_]]

On Tue 2011-Jul-05 13:38, William Sommerwerck writes:

Would you care to expound on when one might use a
weighted and when C weighted, since that would be his next
question, and would probably be beneficial? In fact, if we
were still updating the FAQ that might be a good addition.

As I and others said, the A weighting mimics the response of the ear
at low levels. That should be self-explanatory.

INdeed, but you probably wouldn't be surprised at the number of times I've seen, both in this group, and in
alt.audio.pro.live-sound folks asking which scale to use on
their rat shack meter they bought to see how loud the band
is at foh position g. From the nature of the questions
the op usually asks I figured Scott was a good one to
expound on the subject a bit, because he goes into enough
detail that the neophyte can understand it. YOu and I both
have the habit of assuming folks understand what they really don't.
NEither one of us were cut out to be teachers methinks g.


Regards,
Richard
--
| Remove .my.foot for email
| via Waldo's Place USA Fidonet-Internet Gateway Site
| Standard disclaimer: The views of this user are strictly his own.

[Scott Dorsey]

Richard Webb wrote:
On Tue 2011-Jul-05 13:38, William Sommerwerck writes:

Would you care to expound on when one might use a
weighted and when C weighted, since that would be his next
question, and would probably be beneficial? In fact, if we
were still updating the FAQ that might be a good addition.

As I and others said, the A weighting mimics the response of the ear
at low levels. That should be self-explanatory.

INdeed, but you probably wouldn't be surprised at the number of times I've seen, both in this group, and in
alt.audio.pro.live-sound folks asking which scale to use on
their rat shack meter they bought to see how loud the band
is at foh position g. From the nature of the questions
the op usually asks I figured Scott was a good one to
expound on the subject a bit, because he goes into enough
detail that the neophyte can understand it. YOu and I both
have the habit of assuming folks understand what they really don't.
NEither one of us were cut out to be teachers methinks g.

The problem is, I used to know the answer, but I am less and less sure.

The A weighting is supposed to measure the audibility of a sound, but
in fact that's not really as useful as you think. It is a very poor
measure of the annoyance level of a sound or of the hazard level of it.

The C weighting is supposed to be as close to flat as was possible with
a particular kind of ceramic microphone that no longer exists. Modern
meters (which are capable of much better low frequency response) are
basically handicapped by making them match up to the C weighting.
It's probably a better measure of the annoyance level of a sound.

BUT, the noise ordinances in most cities are based on A-weighted
measurements. Maybe this is because of lobbying from nightclub owners
whose clubs leak a lot of low end. Maybe it's because the A-weighting
is intended to measure audibility. But it makes those ordinances useless
against low frequency sources (like stamping mills and nightclubs).
However, determining legality under those ordinances is probably the only
good use for A-weighting these days.

Really, neither one of them do what people want them to do today.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[hank alrich]

Richard Webb wrote:

On Tue 2011-Jul-05 13:38, William Sommerwerck writes:

Would you care to expound on when one might use a
weighted and when C weighted, since that would be his next
question, and would probably be beneficial? In fact, if we
were still updating the FAQ that might be a good addition.

As I and others said, the A weighting mimics the response of the ear
at low levels. That should be self-explanatory.

INdeed, but you probably wouldn't be surprised at the number of times I've
seen, both in this group, and in alt.audio.pro.live-sound folks asking
which scale to use on their rat shack meter they bought to see how loud
the band is at foh position g. From the nature of the questions the op
usually asks I figured Scott was a good one to expound on the subject a
bit, because he goes into enough detail that the neophyte can understand
it. YOu and I both have the habit of assuming folks understand what they
really don't. NEither one of us were cut out to be teachers methinks g.

Back in the 1970's if you opened one of those Radio Shack SPL meters
you'd see the H-P logo on the circuit board! Mine from that era got
swiped.


--
shut up and play your guitar * http://hankalrich.com/
http://www.youtube.com/watch?v=NpqXcV9DYAc
http://www.sonicbids.com/HankandShaidri

[Mike Rivers]

On 7/5/2011 2:49 PM, Richard Webb wrote:

WOuld you care to expound on when one might use a
weighted and when C weighted, since that would be his next
question, and would probably be beneficial.

A weighting, because it approximates the sensitivity of the
human ear, is what's used for determining a single number
for sound level that's typically used to determine a harmful
sound environment. C weighting, though not flat, is the
closest to flat on the low end, with a 10 dB hump around
about 3 kHz, tapering down linearly above that so it's back
to 0 dB around 15 kHz.

C weighting is most useful for determining the maximum SPL
in PA and theater systems, and is sometimes used in long
term monitoring. People trying to escape from the Music
Police like A weighting because it attenuates of a lot of
the low end that gets you dancing.



--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff

[alex]

Il 05/07/2011 2.57, ChrisCoaster ha scritto:
I know that A-weighting approximates human sensitivity and C-weighting
is "flat".

But which one is "pink" and which is "white"??

For once and for all set me straight on the terminology.

-CC

none of them. No direct relation.
A "weighting" curve is a specific kind of *equalization* *curve*, while
white and pink noise are randomly generated *signals* with a specific
equal power content per frequency or octave.
"c" weighting is not really a FLAT curve but contains rolloffs for highs
and lows well inside the hearing range.
Weighting curves are used to "correct" the measurement microphone output
to better fit some particular measurement purpuse.
"a" weighting is derived by the family of human ear sensibility curves
(although the concept of human sensibility is more complicated and
depends largely on the nature of the sound itself), and help the
measurement to best fit the way humans hear sound, which is not flat...
take a look to the fletcher-munson curves.

alex