Putting on my super-crypto-decoding hat:
Word 1 starts with a U. I think it's Use.
Word 3 starts with a G. As we're talking of searching for info, it must
Word 4 starts with a Fuh. Like Ferry, as in Gerry and his Pacemakers. But
here I think it's another 3-letter job; specifically, "for".
Word 6 then pops out as the four-letter word "sake".
Words 2 (or at least its unparticipled root) and 5 are spelt out with a
single transposition error on T-shirts bought overpriced (or knockoffs
at market stalls) by wannabe rebelious yoof. Yeah, go on, rebel: be
just like all the other induhviduals making a personal fashion statement
against global capatalism by buying up the image of a global brand...
Hey, Andy, can I have that job at GCHQ now? ;-)
On 14 Oct 2003 08:27:55 GMT, email@example.com wrote:
Over 25 years ago I was in HP Grenoble on a training course. Dave
Packard was in town holding some meetings around Europe. He did a
presentation in the staff canteen - with John Young who was CEO prior
to Lew Platt (showing my age now...).
Absolutely brilliant podium speakers, both of them. Highly motivating,
easy to see how HP got to where they did. It was sad when Bill and
Dave were no longer part of the company, things changed significantly
at the sharp end of customer sales and support where I was based.
HP Labs in Bristol - been in there a few times on fleeting visits.
Wonderful place. Pinewood was the other UK facility where it was real
nice to work - drove past there yesterday, bit of a shame to see the
For Sale hoardings outside - I remember the UK MD announcing in the
Winnersh canteen that it was being opened.
1dB is reckoned to be about the smallest difference you can detect
listening to a pure tone; 3dB is about the smallest difference for
All other things being equal, 43dB will sound noticeably quieter than
db sometimes ...dBA at others ....the dBA is used more often as the human ear
is not as receptive at some frequencies as at others. The dBA values take this
into account. There are also other db variations.
Pressure ...power ..intensity....
50 dBA is low and 40ish extremely low!
As a very rough rule of thumb (with all sorts of caveats), 10 db
equates to a perceived difference of 2:1, thus 10dB greater will sound
twice as loud, and 10dB lower will sound half as loud. Similarly, a
3dB change will be detectable if switched quickly from one level to
the other, but not detectable in a longer-term comparison test (using
a chi-squared test for example). Bear in mind that the response of
the ear is quasi-logarithmic, rather than linear.
I have my eye on that AEG too for the same reason.
Lets us know what's it's like if you purchase it?
PS Can I just point out that a baby can cry at 115dB! -somewhere between a
pneumatic drill and a rock concert in front of the speakers. Hearing damage
starts at 90dB.
Many thanks for all the replies. Off work yesterday but read them all this
morning. I've learnt alot again. Oh how I wish I made more attention at
school. Logarithims and noise levels we must have studied it but sure as
hell have forgotten. Well as 43db is 10 times quieter than 52 then the AEG
will be the one
It's not exactly clear what "10 times" means... Almost certainly not that
you could have 10 of them on at the same time and only making the same
amount of noise as 1 of the louder variety. Fwiw (and there are some sound
gurus lurking around here), I believe the average ear can only discern a
change of about 3dB (maybe 2). 10dB is perceived as an approximate doubling
in volume, iirc.
Nevertheless, the quieter machine will be noticeably quieter, but perhaps
not throughout its full cycle. They probably use some averaging algorithm
to quote results.
I'm fairly certain the origin of the decibel (or bel, of which it is a
tenth) is that it is the minimum change in level that the average ear can
determine in its most sensitive range. 3dB might well be a more practical
amount, though, as an average across the audible spectrum.
I'd hope they're quoting the peak level, and it should be 'A' weighted to
take into account the varying sensitivity of the ear to different
*What do little birdies see when they get knocked unconscious? *
Dave Plowman firstname.lastname@example.org London SW 12
Nah, the magnitude of a decibel is simply based on 1/10 of a log10 and, so,
is mathematically determined. However, you may be getting confused with your
story, as when calibrated for use as a noise measure, 0dB is set at a
standard threshold of human hearing level by convention.
Actually no - it's a "dimensionless" unit, 'cuz it expresses the
ratio of one measurement [in this case of a sound level] to another
measurement of the same thing. So the 'base of the unit' as you
put is divided away to nuttin'. And hence the insistence of the
pedants on saying "you can't give a value in decibels without
also giving the reference value"; they're right in an anal sort of
way, but for common level measurements there's a widely accepted
reference level - for audible sound pressure 0dB is "person with
good hearing (barely) can't hear it [but if it's made a bit louder
they will]; for audio levels it's 0.775V into 600 ohms if I recall
correctly. To express a wide range of ratios with smaller numbers,
we then take the logarithm of the ratio, so that a difference in
level of 1000 times is 3 bels (1000 being 10*10*10 - three tens),
a difference in level of one-hundredth is -2 bels (1/100 being
1/(10*10) - two tens on the bottom). And in a final twist to
confuse the unwary (maybe for marketing reasons? gawd knows) we
use the decibel, tenth-of-a-bel, for common use; so a ratio of
100 gets called 20dB, a ratio of a million is 60dB, and a doubling
is just about 3dB, since the base-10 log of 2 is about 0.3010 from
memory (you can tell I went to school when log tables were still
standard issue - but only just!).
It's as if we measured speeds as a ratio to some Standard, say a
British Standard Walking Speed of 4mph. Then a speed of 30mph would
get called "7.5", a speed of 1mph would be called "0.25", and so on.
If the Metrication Council then demanded we recalibrate the
British Standard Walking Speed to be expressed as 6.437376 km/h,
the 30mph = 48.28032 kp/h would still be called "7.5" (wot with
48.280832 being 7.5 times bigger'n 6.437376). The underlying
arbirtrary unit has been divided out, leaving the "dimensionless"
Almost correct - I think? Except 0dB in audio is actually 0dBm which equates
to 1mW into a resistive load, by convention accepted as 600R unless
otherwise stated. 1mW into 600R is almost exactly 775mV.
Indeed. And with 'voltage' dBs, which will be the type used for quoting
the loudness of appliances etc, 6dB is a doubling of the actual voltage
measured. 3dB is a doubling of power, so applies to amplifiers, etc.
*He's not dead - he's electroencephalographically challenged
Dave Plowman email@example.com London SW 12
Just in case any confusion has been introduced by talking about
"types" of dBs, there is no such thing as a "voltage dB" or a "power
dB". A dB is a dB, i.e. a specific ratio, which by definition is
measured in power, but which can also be measured in voltage (or in
current come to that) as long as the two measurements share a common
Provided that the ratio is adjusted in line with the variable's relationship
to power. Power is related to the square of voltage, so multiplication of
ten in voltage terms is not 10dB, but 20dB.
An example in numbers with a 1 ohm resistive load:
1V rms produces 1W (call this 0dB)
10V rms produces 100W
This is a 20dB amplification, as although it gives 10x the voltage it gives
100x the power, which is expressed as 20dB.
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