On 30 April 2015 at 14:55, Tanu Kaskinen <tanu.kaskinen at linux.intel.com> wrote: > On Wed, 2015-04-29 at 21:12 +0200, Wilck, Martin wrote: >> On Mi, 2015-04-29 at 19:17 +0300, Tanu Kaskinen wrote: >> >> > > The graphical volume controls don't reflect this; thus user control >> > > input volume is almost impossible at higher levels than 25%. Volume will >> > > appear to change non-predictably to users. >> > >> > PulseAudio compensates coarse hardware volume by applying software >> > volume when necessary. This means that users get a smooth volume curve. >> > For example, you presented a nice table of different volume levels, and >> > there was this line: >> > >> > PA(%) PA(dB) Captu Boost Capture+Boost-66dB >> > 56% -15.00 30.00 12.00 -24.000000 >> > >> > The ideal situation would be where the second and the last column would >> > be equal, but in this case there's a 9dB difference. But no worries, >> > PulseAudio compensates that by amplifying the signal by 9dB in software. >> >> OK, I didn't know that. Thank you. I still think that Pulseaudio should >> rather apply the hardware volume control in "coarse first, fine later" >> order, eliminating the need for software volume compensation (which >> would infer distortion unless I am mistaken). > > Yes, software amplification will in general cause a more noise than > doing the same amplification in hardware (assuming an analog amplifier), > but as you pointed out yourself earlier, we can't just switch the > Capture and Boost control order, since on some hardware the Boost > amplifier is very noisy. You're probably right that the Boost control > should be separate from the normal volume slider, but we don't currently > have a mechanism to expose the Boost control in UIs. We do have the idea of a base volume that provide UI hints for this case. -- Arun
