solved? Re: [linux-audio-user] [OT] recording levels (mismatch)

MarC marc_contrib at ramonvinyes.es
Fri Oct 15 16:16:17 EDT 2004


Mark Knecht wrote:

>On Fri, 15 Oct 2004 17:11:50 +0100, anahata <anahata at treewind.co.uk> wrote:
>  
>
>>On Fri, Oct 15, 2004 at 08:19:36AM -0700, Erik Steffl wrote:
>>
>>    
>>
>>>  sony STR-SE581
>>>  voltage 150mV
>>>  impedance 10kOhms
>>>
>>>  the creative.com knowledge base search revealed:
>>>  Line In Full Scale Input 2.0 Vrms
>>>  Line In Impedance 10k ohms
>>>
>>>  what is Vrms? I guess it has something to do with voltage... should
>>>2.0 Vrms play nicely with 150mV?
>>>      
>>>
>
>  
>
rms is a way to mesure AC voltage,
In case of a sine, 2Vmrs corresponds with a sine of 2*sqrt(2) V of 
amplitude.
take a look at http://www.doctronics.co.uk/rms.htm
(it's always good to learn new things :)

>Basically that a 2V sine wave on the input of the Sound Blaster would
>give you full volume.
>
>On the other hand, if the Sony only puts out 150mV at full volume then
>you are not driving the SB very hard.
>
>Couple this with a 10K output impeadance and a 10K input impedance and
>your 150mV is cut in half to 75mV into a 2V input. That's pretty low
>in my mind...
>
>
>
>  
>




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