Sorry - I misremembered the numbers completely (recording is from 20hz to 20khz, so 60khz is just stupid on my part)... back to the books:
http://en.wikipedia.org/wiki/Vocal_range
Wikipedia said:
In terms of frequency, human voices are roughly in the range of 80 Hz to 1100 Hz (that is, E2 to C6) for normal male and female voices together.
So 6Khz, not 60 (thanks for catching that so I don't sound like a complete idiot when someone goes looking fruitlessly for the filter that can trim that high) is where I start (obviously, I don't just do it blindly, I have good headphones on and adjust it until it just starts cutting into the voice, then back off slightly) -- I was simplifying for the sake of brevity (incorrectly too

). If the filter cuts too deeply, I always back off to preserve the natural sound as much as possible.
As with any endeavor in visual/audio media, the numbers will only take you near the result - the rest is up to YOUR senses as a craftsperson. All sounds have higher frequency harmonics produced not just from the voice itself, but from the environment and even from the recording equipment. Things vibrate... that becomes part of their sound as we perceive it. Choosing to keep or eliminate those harmonics is how we sculpt the sound to fit in the overall soundscape.
I think one of the hardest things for folks coming into audio to grasp is the concept of layered frequencies as a cohesive soundscape. The reason orchestral music seems so large is that it very delicately uses the tonal ranges of all the instruments to fill the soundscape from top to bottom. Variations of rhythm in each of the instruments create a fluctuation back and forth from lows to highs that can suggest a rhythm separate from the actual beat of the piece or even the individual instruments. An instrument of a specific frequency (range) played louder than other instruments in a similar range will suppress the listener's perception of the quieter instrument at the same frequency. In recorded audio, this phenomenon has to be created rather than happening naturally as the waves are blended at the source (speaker) rather than naturally overcoming the waveforms.
For an example of this, listen to the soundtrack on Altman's "MASH: the movie". The vocals are difficult to pick out due to all the mingles sound sources at the same frequencies. This was a choice he made that drives me crazy (perhaps the intention)... and it's how I hear in crowds - which is why I don't like crowds, it's physically painful (sidetrack). In the same way that we can draw the viewer's eye to a section of a frame by slightly darkening the rest of the frame with a vignette/power window effect, wee can do the same in the audio by slightly "dimming" the frequency range the part we want to focus on in all of the sound sources other than the one we're emphasizing. As with the vignette, this doesn't have to be a extremely pronounced effect, subtle changes will do a better job by having the effect not be noticeable.
I've completely tangented here and will now return you to your regularly scheduled program.