There’s two ways you can learn if they are clashing or not:
Listen. Seriously, if you have trouble hearing the kick or the bassline when both are playing together, you have a problem. Always trust your ears over any other method, this is music after all.
Look. Get yourself a copy of the free plug in “Inspector“. Look at the frequency spectrum of both the kick and bassline seperately, this is the default view of Inspector BTW, so it’s very easy to do. This way, you can easily see what frequencies are present in both instruments, and if they are clashing/peaking at the same time.
Once you start doing this more and more, you’ll learn what to listen for and won’t need to rely on looking at a spectrograph.
-rEalm
Inner Portal Studios
http://www.soundclick.com/innerportal <- For MP3’s