Krishna,

Note: I max out my speakers, but not headphones.
Speaker output on my laptop is too weak otherwise,
and if it seems louder than I use with Win7, I
just turn it down with panel VC. Seems safe enough.

Having maxed my PCM, I can't say for sure I have
not hurt the headphone channels. But I don't
have any headphones, and probably won't use that
capability anyway.

I'm really fond of the nice gui that alsamixer
shows on an LXTerminal.