Sounds to me like you could use "compression." See if school will spring for inexpensive "compander" (compression-expander in one unit) like a used DBX 2BX on eBay. Once popular in '70s, out of favor now because CDs have more than enough dynamic range. What you want is less dynamic range (or compression) at low volume levels to reduce peak dynamic range levels at low volumes & people usually play music loud enough not to need expansion. Installs easily in tape monitor loop. Good luck.
You can probably read better definitions than I could give you on "compression-expansion" on WWW or in product description at eBay.
You can probably read better definitions than I could give you on "compression-expansion" on WWW or in product description at eBay.