measuring low end frequency response in my room.

[Ethan Winer]

There are three good programs, two affordable at $150 and one free:

Windows: ETF Acoustic Measurement Software
Mac: FuzzMeasure Pro 3
Both (and free): Room EQ Wizard Home Page

Here's an article that explains how I use the ETF software:

RealTraps - Optimizing Acoustic Treatment using ETF

If you have follow-up questions, you'll do best to ask in the Studio Building or Bass Traps sections here at Gearslutz.

--Ethan