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-s....

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