If you have a severely compromised playback system (whatever the cause), it can be useful to use analysis/mastering tools to equalize the audio. Professionals will look down on this approach but it will generally produce better results than an inexperienced producer in a compromised space.
I always run Roger Nichols (free) Inspector plug-in as the last device on the mix down bus when I work on my recordings.
http://www.kreativsounds.com/roger-nichols-digital-inspector/It's very useful for getting the channels balanced, seeing what the frequency content of your recording is and detecting clipped samples.