Using a letter of recommendation from freshman year professor? I am an electrical engineering senior, and I am preparing to apply to Master's programs in three different fields: communications engineering, embedded systems, and computational engineering. I need two LORs for each program. The problem for me is that my best recommenders are professors from my freshman and sophomore years. My grades, classroom-interaction, etc. actually deteriorated after that point.

I have identified four potential recommenders, but I ruled out one of them (a comms prof) because he indicated to me that his letter will not be very good.

My remaining options are:


A Microwaves professor with whom I have taken several courses and gotten A-,B+, and B. I got the A- in a 300 level course I took as a sophomore. 
A networking professor with whom I got a B+ recently, and had at least minimal interaction. 
A math professor with whom I got an A in a 200 level course (multivariable calculus) as a freshman, and had plenty of interaction. Math was my passion at that time. The prof also encouraged me to become a math major.


My dilemma is: a LOR from number 3 is possibly so much more positive than 1 and 2, but it is for a 200 level course that is not engineering. I don't think it is very relevant to any of my target fields (communications, computational engineering, and Embedded systems). And, I took that course three years ago. I was a different person, socially, academically, motivationally, philosophically, etc. Should I rule out number 3?
In short: if you don't have better letters of recommendation, then you should go with the ones that you have available.

If the best letter you can get is from a non-EE person, I wouldn't rule it out on that basis alone. If the person can comment on your potential as an EE, that would make things better still.