You should also know that Shaw takes commissions at a minimal fee. You also have to mention my name in your credits song by Adam Vitovsky. The best thing about getting your background music from SoundCloud is that the tracks sound more like real music, as opposed to a contrived track made for a marketing video.
Public domain compositions are created by a composer who has been deceased long enough that the intellectual property becomes public domain. If you want to convey power and strength alongside a voiceover, try using instruments in the low frequencies bass, for example.
Below is a chart that can act as a simple guide to considering the emotional impact of instrumentation and frequency.
One of the added bonuses of music-only marketing videos is that they make great content for social networks that auto-play videos without sound to begin with. All you have to do is to attribute the owner of the track.