[alsa-devel] What does 0dB refer to? (Logitech USB Speakers)

James Courtier-Dutton James at superbug.co.uk
Sun Apr 13 14:09:23 CEST 2008

Florian Faber wrote:
> On Sunday 13 April 2008 12:51:54 James Courtier-Dutton wrote:
>> Are the output levels from the line out/speaker out connectors really
>> any different between pro and cheap sound card?
> The electric levels do differ. But that's not the point. The point is 
> that you usually have active speakers and 0dB means full throttle. You 
> don't have anything to alter the volume between the sound card and the 
> speakers.
> To give you an impression: My main out is -40..-36dB for work. If I want 
> to talk to another person in the same room, I have to dim to -46dB max. 
> If I throw a party, it might go up to -20..-15dB. 0dB will just pop out 
> the ear drums.
All active speakers act as a combined amp and speaker.
If you have a 50W active speaker, your -36dB for work might be right.
But, if you have a 300W active speaker, your -36dB will probably be way 
too loud.
This is essentially my point that the sound card cannot really decide 
which is a sensible level to output.


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