Hello,
As you develop the 2.0 version and set defaults I would like to argue
the case for the use of non-flat volumes - in other words, change the
default config file for pulseaudio (as part of the Gnome Shell
desktop) at /etc/pulse/daemon.conf (flat-volumes = yes -> flat-volumes
= no)
The default behaviour changed to use flat volumes some years ago.
This is disadvantageous for the user experience.
1. Flat volumes effectively render the master volume pointless.
(A) Moving the slider down only lowers the volume of streams that
were set at the same level that the master volume was.
(B) If any stream moves above the master volume, the master volume
moves up, but this is just cosmetic, since the master volume does not
set any limits. The only effect is that moving streams altogether will
now be changed and all streams move in tandem in different ways
(C) If any new streams open at 100%, the master volume is set at
100% while old streams remain low, destroying any proportionality you
would want to keep by just moving the master volume slider.
(D) The master volume is not truly a master volume. Each individual
audio output stream is actually an independent stream that controls
the audio card directly and is irrelevant to whatever level the master
volume is set.
2. Flat volumes do not behave like physical mixers, which are the
source for the concept of and the source for the visual representation
of a "master volume".
(A) In a real mixer, or with flat volumes disabled, the master
volume controls the audio card. Each stream remains always a
proportional equal to or less than the volume. So if some programme
outputs at 100%, it will be 100% of the master volume.
(B) Moving the master volume will not ever affect the volumes of
audio streams relative to one another.
(C) The addition of new inputs will not affect the max output level
set by the audio card. No unauthorized raising of master volume.
3. Accessibilty and safety
(A) If flat volumes are userd, then any new stream (like System
sounds, one that comes and goes) could open at 100%, raising the
master volume, but more importantly it would output at max volume
allowed by sound card. Since Tails is used often discreetly, the usage
of headphones is to be expected. The shock of sudden jumps in volume
is dangerous.
(B) Since those who care or know about this and those hwo have it
explained prefer non-flat volumes in the majority and since Tails is
strict about its persistence, the flat-volumes default will
inconvenience most users and they will not be able to configure it a
persistent way (not even per-user through ~/.pulse)
4. User expectations and general preferences
(A) The argument of "That's how Windows does it and WIndows is
widely used" is not an argument for a good user experience.
(B) The previous argument is not true. Before Vista, Windows did
not have flat volumes. It also lacked the integration of
in-application volume sliders and stream volumes like many poorly
integrated ALSA or Pulseaudio audio players on *nix.
(C) Even post-Vista, Windows flat volumes do not behave like Pulse
in flat volume mode. It is more like a hybird of the two. So it is
inappropriate to hold up Windows since it does not behave like
Pulseaudio does.
(D) The volume slider on some pairs of headsets behaves exactly
like the true/traditional master volume concept.
(E) Downstream of Debian is Ubuntu and its re-spins and
derivatives. These overwhelmingly form the majority of desktop Linux
installations and are the first experience most have with *nix on the
desktop.
There is a long discussion at reddit at
<
www.reddit.com/r/linux/comments/2rjiaa/horrible_decisions_flat_volumes_in_pulseaudio_a>
The very problem described in the reddit original post was experienced
often, I believe, by Chris Fisher of Jupiter Broadcasting (Linux
Action Show etc) this month. He blamed KDE for not preventing it. I do
not know what caused him to have his volume spikes, but I switched to
non-flat years ago for because of this problem and I know that Chris
Fisher's usual distro is Arch, which uses flat volumes. So I am
guessing he takes flat volumes for granted or is unaware/forgot that
non-flat volumes are a thing on desktops and is suffering from the
same problem.
Flat Volume PROS: default (but Tails changes defaults all the time) as
advocated by Poettering and is somewhat similar to Windows Vista and
post-Vista
Flat Volume CONS: Reasons mentioned above.
Using flat-volumes when users do not want them, in the worst case
scenario, blows out their ears, causing damage.
Using non-flat/normal volumes when users do not want them, in the
worst case scenario, makes you unable to instantly make a given stream
play at the absolute maximum volume of your sound card If stream TOTEM
is 50% and Master Volume is 83%, then, in order to get TOTEM to play
at the absolute maximum of the sound card, then you have to raise the
Master volume on the panel or through media keys and also move up the
slider in the TOTEM window.
The urgency to raise the volume on TOTEM is outweighed by the need to
prevent sudden alerts coming in and playing at the maximum volume of
the sound card.
