Knocking sound front driver side

2001 ford taurus se with 120,000 miles. In the past 2 weeks I have started noticing a knocking sound coming from the drivers side front suspension when car travels over bump or when brakes are applied. I don't believe it is a cv halfshaft problem because it I don't hear sound when turning just when suspension goes up and down. I recently(about the same time I started hearing the noise) had the 2 front tires replaced and front end aligned, but can't imagine it would cause this sound. Any help woud be appreciated.