29 May
2010
29 May
'10
12:33 a.m.
Ralf Mardorf wrote:
-------- Original Message --------
Subject: Re: [LAD] A little quiz about audio measurements...
Date: Fri, 28 May 2010 21:17:38 +0200
From: Ralf Mardorf <ralf.mardorf(a)alice-dsl.net>
To: Veronica Merryfield <veronica.merryfield(a)tesco.net>
CC: Linux Audio Developers <linux-audio-dev(a)lists.linuxaudio.org>
References: <20100528123116.GA4058@zita2>
<AANLkTimYc_TFtVixHNTCRXvj3n_LtCJQzOsyKFnXiXTh(a)mail.gmail.com>
<20100528153747.GF4042@zita2>
<AANLkTim-FH9FRjAxxL9fwZ1nSG5K2yv3AXTYmpX9_BHN(a)mail.gmail.com>
<4C000DC7.1030709(a)alice-dsl.net>
<719832DC-9545-4B5A-8D5E-EE5F7F962867(a)tesco.net>
Really OT, but maybe anyway interesting, regarding to a German Wiki,
http://de.wikipedia.org/wiki/Netzfrequenz:
Because of magnetostriction of the ferrite core, the sound of
transformer stations is at 100 Hz. Dunno if this is the same for
transformer in our power supplies too.
The load of the public power supply will change the frequency in Western
Europe < 0,2 Hz. When there was a blackout at 11/04/2006 the frequency
change like this:
http://de.wikipedia.org/w/index.php?title=Datei:Netzfrequenz_20061104_Area_…
Regarding to the German Wiki http://de.wikipedia.org/wiki/Unterfrequenz
all power stations need to disconnect at 47.5 Hz. At 49.8 Hz there is an
alert.
We should assume that the frequency in Western Europe is solid 50.19 to
49.81 ;).
[snip]
OT followup:
Oberhausen, Rheinland, Germany; power line frequency right now is at
49 Hz, measured with a low cost energy consumption costs meter. Those
low cost meters shouldn't be able to do correct measurements ;). The
best test at home might be to compare the sound of a transformer with
a 50 Hz sine wave. The times I have measured the power line
frequency to check it's
effect or otherwise, I have not measured it as exactly
50.0hz (when I
lived in the UK). >
Vrnc
[snip]
