2010/6/15 Lennart Poettering mznyfn@0pointer.de
On Mon, 14.06.10 11:22, Colin Guthrie (gmane@colin.guthr.ie) wrote:
'Twas brillig, and James Courtier-Dutton at 14/06/10 09:56 did gyre and gimble:
On 14 June 2010 09:33, Colin Guthrie gmane@colin.guthr.ie wrote:
'Twas brillig, and Raymond Yau at 14/06/10 01:25 did gyre and gimble:
if your sound card have ac97 codec ., you can use audacity to record
the
output from hw:0,0 and you will see clipping occur when you set "PCM"
volume
above 0dB
So the standard response is "don't do that then" :)
That's why the base volume is shown to the user via GUIs so that they can gauge the best point on the slider to use. Currently there is no indication with alsa sliders at which point the 0dB "sweet spot" lies.
What do you mean. If you use "alsamixer", dB values are shown so it is easy to find the 0dB "sweet spot". I think it is pulse audio that hides this information when it combines two alsa mixer controls into one pulseaudio control.
But it doesn't hide it. It's shown very clearly in the volume control GUIs as the Base Volume.
Let me also stress that "dB" is not at all understandable to most people. It is a very technical unit, and showing 0dB in the UI just like that won't be very helpful for most people.
That's why we thought about this, and are recommending a color coded slider to be exposed in the UI which encodes the range information in a sane way that is intuitively understandable by users. In green, in yellow and in red. (meaning hw attenuated, hw amplified, sw amplified ranges)
http://pulseaudio.org/wiki/WritingVolumeControlUIs#Colouredvolumesliders
Lennart
Clipping may occur at recording if there is gain above hardware 0dB point , the region should be coloured as red ,
What is the meaning of the yellow region ?
For HDA base volume seem to be at the same point as the norm volume since max_db of playback is 0dB
+12dB(400%) is even larger than the software gain 150% of PA