Yup i have few of those here. You could still try some Software solutions too.

try TrueRTA and Visual Analyser, to me, they look good for some freeware.

Visual Analyser
http://www.sillanumsoft.com/

TrueRTA
http://www.trueaudio.com/

I didn't used them, i use Smaart Pro, SpectraLab and/or a good ol' Klark-Teknik DN60 RTA for my studio or on the field PA rig tune-up.