[LAD] A little quiz about audio measurements...

[Ralf Mardorf]

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 at alice-dsl.net>
> To:     Veronica Merryfield <veronica.merryfield at tesco.net>
> CC:     Linux Audio Developers <linux-audio-dev at lists.linuxaudio.org>
> References:     <20100528123116.GA4058 at zita2> 
> <AANLkTimYc_TFtVixHNTCRXvj3n_LtCJQzOsyKFnXiXTh at mail.gmail.com> 
> <20100528153747.GF4042 at zita2> 
> <AANLkTim-FH9FRjAxxL9fwZ1nSG5K2yv3AXTYmpX9_BHN at mail.gmail.com> 
> <4C000DC7.1030709 at alice-dsl.net> 
> <719832DC-9545-4B5A-8D5E-EE5F7F962867 at tesco.net>
>
>
>> [snip]
>> > 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]
>>   
>
> 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.

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_1.jpg&filetimestamp=20061112123742

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 ;).