This is when it actually gets useful. For the male voice, the fundamental frequency of the lowest notes one speaks is between 85-155 Hz. For a female, it’s a little higher, perhaps 165-225 Hz.
This means that there is no real information that we need below 85 Hz for males and 165 Hz for females.
And in reality, because of the way we hear and the way the voice is produced, there are plenty of harmonic frequencies that our brain will interpret clearly to make up for missing fundamentals.
So let’s say we have a refrigerator running in the background of a female interview. We can safely dial up a HPF with a threshold of 165 and not loose any of her voice.
We can take it up even higher to eliminate more of the noise, and the clarity will improve markedly.
In fact, the voice will “sound” louder once the low frequency stuff is removed because we can hear it better.
So this is exactly what we did for grocery store woman. We dialed up an HPF with a threshold at around 150 Hz, and it totally transformed the audio.
There was still some higher frequency noise, and it was obvious she was standing in the store and not a studio, but the clarity of here voice was improved substantially.
Earlier I mentioned we actually have 2 tools in our tool belt. The other one may be on the mic itself. Many professional shotgun mics (and some interview mics, and the occasional lapel mic) have a HPF built in.
For example, my beloved Audio Technica 835B has a switchable roll off at 180 Hz at 12 dB per octave. That means at the lowest fundamental of a male voice the mic will be 12 dB down, which is generally not a big deal unless you’re interviewing James Earle Jones.
Normally, I like to leave this switched on because it eliminates a lot of room rumble, AC noise and other nasties right at the source.
It’s just a good idea. If you use this when you shoot, you will require less processing in the edit suite.
Of course, you’ll want to listen to it through some good headphones first to make sure you’re happy with the sound. You do have good headphones, right?
Do you ever run up against audio problems when producing worship videos? I’d love to hear about them in the comments below!
Mike Sessler is the Technical Director at Coast Hills Community Church in Aliso Viejo, CA. He has been involved in live production for over 20 years and is the author of the blog, Church Tech Arts . He also hosts a weekly podcast called Church Tech Weekly on the TechArtsNetwork.