Change your pick?
Epiphone SG
Crate V-18 212
Xaviere XV-500
Boss PS-5 SUPER Shifter
Digitech Bad Monkey

were the guitars at college also nylon string?
- Art & Lutherie Cedar CW (SOLD! )
- Martin D-16RGT w/ LR Baggs M1 Active Soundhole Pickup
- Seagull 25th Anniversary Flame Maple w/ LR Baggs Micro EQ

Have an acoustic guitar? Don't let your guitar dry out! Click here.
Where on the strings are you picking?
If its closer to the bridge you're going to get a more pluckier sharper sound.
it's all just coming back
it's all coming back

it's all coming back to me
The strings on the guitars at school might be more worn, sounding less lively, making your guitar sound different.

A few things to consider, before you drive yourself crazy.

Is your guitar a solid top, or laminated? How about the guitars at school?

For example, if your guitar is solid top, and the school is laminate tops, then they will sound different.

If you use different strings than the school uses, the guitars will sound different, yet again.

If their strings are worn out, and yours are newer, then the sound will again be different.

Too many variables.