kHz - the frequency range the headphones will play. I'm not sure the limits of human hearing, and I know as you age you lose the ability to hear higher frequencies. When you're talking 8 & 12 hz you're talking pretty dang low. Music really doesn't get that low. 25kHz - 38.5kHz is really really high, as in you probably can't hear it. We're talking the highest pitch whines you might hear coming from electronics.

Human hearing at best is 20hz to 20khz. You can feel vibrations from lower than 20hz but you can't hear them.

It's also pointless getting something that plays frequencies above 20khz since CD music is sampled at 44.1khz and band limited, which means those higher frequencies don't even exist in the audio file.

Ω - Ohms of Resistance (AKA Impedance). This is the electrical resistance of the speakers. The higher the # the more power it takes to drive them.

And generally, the higher the resistance, the better the headphones. My wife was telling me that while she loves her 280 Pros, they eat the batteries on her iPad much faster than any of our other headphones. So if you want mobile, be prepared to sacrifice battery life. If you get headphones with their own preamp that can reduce the battery drain because you have an external battery powering the headphones.

Also, if you just want to listen to music, you are probably better off with a closed design as opposed to an open one. You'll get better bass from the closed design.

This technique works because the source is 5.1 sound and there is a center channel. Most music is just mixed in stereo and vocals fluctuate across frequencies, mixing in with other instrumentation.

Depending on the label and genre, it is sometimes not so hard to find singles with an acapella or instrumental mix.

Edit: I reread Cody's suggestion and it sounds like that source is just stereo. So.. maybe?

So Cody's suggestion should work well in this instance because voice-over tracks for TV/Movies/Games are almost always perfectly centered in the mix, meaning the voice in the left channel is exactly the same as the voice in the right channel.

Vocals in music are more complicated because there are often multiple layers with multiple takes, spread out to various points in the stereo range. So the voices you hear in the left channel are often not identical to the voices in the right channel. There will be a decent amount of overlap, so it would still partially work, but not as effectively.