On Thu, 28 Jun 2007 13:11:20 +0100, "James Perrett"
wrote:

On Wed, 27 Jun 2007 17:33:39 +0100, Don Pearce wrote:

On Wed, 27 Jun 2007 17:18:01 +0100, "Serge Auckland"
wrote:



"tony sayer" wrote in message
...

http://www.shakti-innovations.com/audiovideo.htm
--
Tony Sayer


What staggers me is the references they give. Do Abbey Road *really* use
stuff like this, and do they know their name is being use by these
people?

Glad to see there isn't a single Broadcaster amongst their references.

S.

They probably sent a free one there, and have based their claim on the
fact that it may, just possibly, not have actually been thrown in the
bin.


Well certain recording engineers seem to use this sort of thing. I know
that Andy Jackson, who does most of the Pink Floyd remasters, uses China
Cones.

Probably trying to recapture the state of mind they all had back in
the sixties.

d
--
Pearce Consulting
http://www.pearce.uk.com

"Don Pearce" wrote in message
...
On Thu, 28 Jun 2007 13:11:20 +0100, "James Perrett"
wrote:


Well certain recording engineers seem to use this sort of thing. I
know
that Andy Jackson, who does most of the Pink Floyd remasters, uses
China
Cones.

Probably trying to recapture the state of mind they all had back in
the sixties.


Which produced a damn sight better 'sound' than they can today.....

"Serge Auckland" wrote in message
news


"Keith G" wrote

http://www.apah69.dsl.pipex.com/show/Signal.JPG


Is reckoned to be 'good' (or 'good enough')...???

(Certainly sounds OK!!)
Keith:-

If I haven't pressed any wrong tits on my calculator,

55dBf means 55dB above 1 femtowatt, or 10^12 watts
55dB is a power ratio of 3.16 x 10^5
so 55dBf is a power level of 0.316 microwatts.

Assuming a standard 75 ohm antenna, that translates to 4.87 mV, so I'd
say that was a pretty good signal.


Hi Serge - I found this in the manual a little earlier:

http://www.apah69.dsl.pipex.com/show/Voltages.JPG

(RTFM was never my strong suit!! ;-)

How does it sit with your figuring? There's a bit of a discrepancy - is
it easily explained?

(Just out of interest and FYI only - no bother whatsoever to me! :-)

"Keith G" wrote in message
...

"Serge Auckland" wrote in message
news


"Keith G" wrote

http://www.apah69.dsl.pipex.com/show/Signal.JPG


Is reckoned to be 'good' (or 'good enough')...???

(Certainly sounds OK!!)
Keith:-

If I haven't pressed any wrong tits on my calculator,

55dBf means 55dB above 1 femtowatt, or 10^12 watts
55dB is a power ratio of 3.16 x 10^5
so 55dBf is a power level of 0.316 microwatts.

Assuming a standard 75 ohm antenna, that translates to 4.87 mV, so I'd
say that was a pretty good signal.


Hi Serge - I found this in the manual a little earlier:

http://www.apah69.dsl.pipex.com/show/Voltages.JPG

(RTFM was never my strong suit!! ;-)

How does it sit with your figuring? There's a bit of a discrepancy - is it
easily explained?

(Just out of interest and FYI only - no bother whatsoever to me! :-)


No, not easily explained.
Take the example of 50dBf = 86.5uV 75 ohm
86.5 uV into 75 ohms is a power level of 99.76 femtowatts, call it 100
femtowatts.
That would be 20dBf in my book *if* dBf means dBs relative to 1 femtowatt.

1 femtowatt is 10^-12 AFAIAC

Consequently, their dBf is not relative to 1 femtowatt, or their femtowatt
is not mine.

According to their figures, you would need a signal strength of better than
80 to get completely (audibly) noise-free audio.

Working back, 86.5uV /75 ohm is 50dB relative to 1 attowatt or 10^-15 watt

S.

--
http://audiopages.googlepages.com

1 femtowatt is 10^-12 AFAIAC

"femto" is the prefix for 10^-15.


Martin
--
M.A.Poyser Tel.: 07967 110890
Manchester, U.K. http://www.livejournal.com/userinfo.bml?user=fleetie

"Serge Auckland" wrote in message
...


"Keith G" wrote


Hi Serge - I found this in the manual a little earlier:

http://www.apah69.dsl.pipex.com/show/Voltages.JPG

(RTFM was never my strong suit!! ;-)

How does it sit with your figuring? There's a bit of a discrepancy -
is it easily explained?

(Just out of interest and FYI only - no bother whatsoever to me! :-)


No, not easily explained.
Take the example of 50dBf = 86.5uV 75 ohm
86.5 uV into 75 ohms is a power level of 99.76 femtowatts, call it 100
femtowatts.
That would be 20dBf in my book *if* dBf means dBs relative to 1
femtowatt.

1 femtowatt is 10^-12 AFAIAC


Probably not, asitappens:

http://en.wikipedia.org/wiki/Atto-



Consequently, their dBf is not relative to 1 femtowatt, or their
femtowatt is not mine.

According to their figures, you would need a signal strength of better
than 80 to get completely (audibly) noise-free audio.

Working back, 86.5uV /75 ohm is 50dB relative to 1 attowatt or 10^-15
watt


OK, disregarding the 'SI prefix' confusion, there's summat not too clear
here but the tuner's been retired pro temps in favour of the....

.....wait for it....

....DAB tuner...!!

As Swim picked it consistently over the FM tuner last night (or the the
night before) as she thought the FM was comparatively boomy and that
there was a feint hiss with a signal strength of about 55 dBf, so your
figure of '80 dBf' for *completely* clean audio might not be too wide of
the mark?

(No good asking me - the FM sounds as 'good as CD' to me!! :-)

"Fleetie" wrote in message
...
1 femtowatt is 10^-12 AFAIAC

"femto" is the prefix for 10^-15.


Martin
--
M.A.Poyser Tel.: 07967
110890
Manchester, U.K.
http://www.livejournal.com/userinfo.bml?user=fleetie


Correct, my error. How could I forget Pico?

What this means is that the tuner's manual is correct, and that you *do*
need a signal level of 80 or thereabouts for stable noise-free reception.

S.

--
http://audiopages.googlepages.com