See the official answer from Grado Labs-info center:   Hi, the SR60 and SR80 are identical in terms of efficiency. Both are the same on a portable device the SR80 definitely has better bass Cheers

Hello , I am writing you from Bulgaria,I am  interested in Grado Sr series. I haven't used them until now because they are not available in my country.I can't try them, but from reading the musical forums i agree they are really good.I want to order from amazon.com - model sr60 or 80. Also...