Raising volume past 100%

[David Griffith]

After reinstalling Debian on a laptop, I once again had to face the 
problem of how to get volume out of the built-in speakers boosted.  The 
last time I reinstalled, I somehow got the MATE volume control applet to 
let me turn the volume past 100% using the mouse wheel.  Over the past two 
days I've been trying to rediscover what I neglected to write down.

I'm already aware that by bringing up the Sound Preferences dialog, I can 
raise volume to 153% and no further.  I also know that I can use
pulseaudio-ctl(1) or pactl(1) to set the volume at any arbitrary level 
past 100%.

I remember that I went looking for solutions other people found for this 
that involved editing /etc/asound.conf or ~/.asoundrc, but the best I can 
get with that is add an extra slider to alsamixer's display that acts as 
apreamplifier.  I was going off of 
http://alien.slackbook.org/blog/adding-an-alsa-software-pre-amp-to-fix-low-sound-levels/.

What could I have possibly done to make this work the last time?

-- 
David Griffith
dave at 661.org

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