I remember the first time I tried to tune a bass guitar. I was playing the bass E string and trying to tell if it was in tune by listening to an equally low note on the piano. I had a very difficult time hearing the right pitches. A much easier way to do it is by using harmonics (chimes) and a regular guitar tuner which is an octave higher.
Notice the arrow on the picture to the right. It is pointing to the 12th fret. If you gently lay your finger on the a string at the 12th fret and play it, you will hear a harmonic chime of the note the string is tuned to only an octave higher. Then just use one of the tuners below. The notes of the strings are labeled on the picture as well.
CAUTION: Remember these pitches are actually an octave higher than the open tuning of the string. Do not overly tighten the strings to reach these pitches without using this harmonic method.
