Audio experts please help

M

michiganfilmmaker

New member
Hi.
Okay, we shot a beatiful film on a nice canon with a 35mm lense adapter. The audio was taped directly into a dvx100b using a AKGck93 mic. (I know its not the traditional way to do it, but its all we had, and i love the combination of the 93 and dvx, it sounds awesome)

Everything was perfect until I got the audio home and listened to it. I discovered that somehow the little tiny button on the ck93 (which i wish was never invented) got bumped somehow to 75HZ.

I know many are familiar with what this setting does, and i have a general idea. But im interested if anyone knows if there is a way to correct it in post with Final Cut Pro audio effects to try and get it back to sounding like if we had just taped it in line, and not in 75HZ.

I have tried raising the highs, lowering the highs, the lows, mids, vice versa, etc. i cant seem to get it sounding like we didnt use the 75hz.

I got a feeling its impossible to correct it, but i thought there might be an audio expert out there who knows a few tricks in final cut pro (i have no other audio software) that can at least help me get it sounding better, and not muffled like it is now.

Any help would be apreciated.
 
The 75Hz switch is a low frequency roll-off. In other words, it removes bass frequencies below 75Hz. It should not have that profound of an effect on your dialog, except that it will lose that low, low end. That's also where a lot of handling noise and mechanical noise reside, so you should be okay. In fact, bass roll-off (aka hi-pass filter) is one mighty handy feature on lots of mics and mixers, seeing as how a distant HVAC unit or fridge, or rumble from an inexperienced boom op can be minimized by using it.

Furthermore, it should not make your recorded audio sound "muffled" at all. "Muffled" indicates the absence of highs and potentially high-mids, and the 75Hz roll-off only affects the bottom end. Did you try swapping cables? If you were using a battery-power capsule, was the battery fresh? Is it possible that the mic got wet at some point?

If you can put up a short clip of the offending audio, it might give us a better idea of what's wrong and/or how to correct it.

And this brings up another concern: was no one wearing headphones plugged into the camera during the shoot? Monitoring audio as you shoot is the best way to avoid these surprises in post.

And what version of Final Cut are you running? If you have Final Cut Studio, you have Sound Track Pro. If you have FCP 4, it came with the original version of SoundTrack. If you have FCP 3, Peak DV came bundled with it.
 
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it removes audio below 75hz at a rate/slope of 12db per octave. If that was turned off, then I would think all you should need to do to correct that is attenuate frequencies below 75 hz by 12 db per octave in post/NLE :).

does this help?
 
Thanks you guys.Okay, maybe im not describing it right when i say muffled. I do know that it sounds different, not as good, as when i tape with the ck93 in "normal" or, i think its called "line" (that little button).. i did a whole feature film right into the dvx and it sounded awesome. The only thing i did differently (on accident) here was use the 75hz thing. I cant describe it, it just sounds a bit wierd. I will definitley post an audio sample when i get home and compare it to an audio sample from my feature film. Your input on how to correct this would be very much appreciated. Also, i think i do have soundtrack. i just dont use it much cause ive never had to. My audio is usually impeccible, which is why this has me so upset.

Yes, we were monitoring, but my audio person said it sounded fine in the headsets-perhaps they werent the greatest headsets, i dont know.
 
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tallrd iw ill try that... . how do i do it in final cut pro? Do i just use that equilizer filter and raise all the frequencies that are below 75?
 
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michiganfilmmaker said:
I do know that it sounds different, not as good, as when i tape with the ck93 in "normal" or, i think its called "line" (that little button).. i did a whole feature film right into the dvx and it sounded awesome.
Click to expand...

Just FYI, it's called "flat."

Again, recording with the bass roll-off shouldn't make things sound that weird. It only slopes off frequencies that normally interfere with clear dialog.

Get that sample posted so we can hear what you're hearing.
 
okay c2.. will do. Thanks for the info.
I will probably have to wait til tommorrow or the next to post it.. so please watch out for it!
Thanks again!
 
michiganfilmmaker said:
Thanks you guys.Okay, maybe im not describing it right when i say muffled. I do know that it sounds different, not as good, as when i tape with the ck93 in "normal" or, i think its called "line" (that little button).. i did a whole feature film right into the dvx and it sounded awesome. The only thing i did differently (on accident) here was use the 75hz thing. I cant describe it, it just sounds a bit wierd. I will definitley post an audio sample when i get home and compare it to an audio sample from my feature film. Your input on how to correct this would be very much appreciated. Also, i think i do have soundtrack. i just dont use it much cause ive never had to. My audio is usually impeccible, which is why this has me so upset.

Yes, we were monitoring, but my audio person said it sounded fine in the headsets-perhaps they werent the greatest headsets, i dont know.
Click to expand...

I'll go even further than the others - it is a "best practice" technique to always have the low-cut filter (the 75 Hz switch) turned ON for dialog recording, only turning it off for music. There should be no perceptible change in the character of the voice unless, perhaps, you're recording Morgan Freeman. What you would hear with it on is a cutting of air mvement and handling noise, which is a good thing to cut. If you're hearing a change in the voice, it's likely that your mic placement is too far from the talent so that you've been picking up excessive reflected sound biased towards the low end.
 
michiganfilmmaker said:
tallrd iw ill try that... . how do i do it in final cut pro? Do i just use that equilizer filter and raise all the frequencies that are below 75?
Click to expand...


when I say attenuate, I mean cut the frequencies (not raise them). I'm not sure how specifically to do it in Final Cut, but i can't imagine it would be too difficult considering this is a pretty bread-and-butter audio editing.

Ultimately, posting a clip would give everyone an equal starting point in order to more accurately help you.
 
michiganfilmmaker said:
tallrd iw ill try that... . how do i do it in final cut pro? Do i just use that equilizer filter and raise all the frequencies that are below 75?
Click to expand...

Why do you WANT to raise the freqs below 75Hz?? Unless you're recording a kick drums, tympani, magma flows, earthquakes, etc there's almost no information down there. Virtually all human voice frequencies are above 120Hz.
 
Steve House said:
Why do you WANT to raise the freqs below 75Hz?? Unless you're recording a kick drums, tympani, magma flows, earthquakes, etc there's almost no information down there. Virtually all human voice frequencies are above 120Hz.
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Exactly.

Even when recording those things I roll off below 80 Hz. I consider anything below 80Hz to be LFE, even with music.

The bass roll-off switch did not make your recording sound bad. Something else happened.

Also, those low frequencies were not recorded, so you can not get them back with an EQ. You can raise what's there, but it won't souond good enough to be worth it. I say forget about trying to get them back. There's nothing below 75 Hz but mud and wind noise.
 
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