filter for working with “roomy” audio

[Bouncing Account needs new email address]

While background hum and certain continuous-type noises are relatively easy to isolate and reduce with special digital filtering…

Reverb/Echo is one of the most IMPOSSIBLE-to-fix of audio problems, second only to severely CLIPPED (over-driven) levels.

“EQ” won’t do it.
Its reverb (repetition) of the PRIMARY audio… the same frequency that you want to KEEP.

The “Noise Gate” is probably the best choice, but it will surely PUMP if its set high enough to have very much effect on the reverb. (So it could end up making many tracks sound worse.)

Whatever you try will adversely affect the overall QUALITY of the audio being “fixed” and be very noticeable to the listener (especially compared to any “good” audio in the same production).

The phrase that applies is: “GOOD audio is the absence of BAD audio.”

Therefore the best cure for BAD audio… is recording GOOD audio.

If it was as simple as adding filters,
major producers of motion pictures and TV shows would NOT spend the big bucks and TIME it takes
to LOOP (replace with ADR) any “bad” location audio with the actors re-recording the same dialogue (lip-syncing) in a quiet studio.

I know that re-recording is not always possible, that’s not my point here.
What IS the point is that once you have a poorly-recorded audio track,
under certain conditions, it just can’t be “fixed”.

— If the VIDEO is out-of-focus and the person talking is not framed correctly:
A. Re-shoot it.
B. Add filters and suffer the obvious reduced quality.
C. Don’t USE it (Substitute another shot.)
D. Suffer with, it as-is.
AND: MONITOR more carefully the next time.

— If the AUDIO is “off-mic” (reverb or echo) or severely over-modulated (clipped):
A. Re-shoot it.
B. Add filters and suffer the obvious reduced quality.
C. Don’t USE it (Substitute another track.)
D. Suffer with, it as-is.
AND: MONITOR more carefully the next time.

[Michael Gissing]

Reverb can’t be eliminated, but selective EQ can help. Often there will be frequencies that are amplified by an accoustic. Big spaces tend to amplify in lower frequencies, so try a narrow notch (HiQ factor) around 120 – 200 hz. Often that will get some of the boomy mudiness out of the dialog. If that helps, try harmonics from 220- 400. Again, fairly narrow notches, or you take the guts out of the dialog.

Forget noise gates. They are just pumping machines that make everything sound wrong. If you know what you are doing with frequency based downward expanders, then you might make a further small improvemnet. Devices like the CEDAR DNS 1000 do this. However, nothing yet can deconvolute so the moral is don’t record in a large concrete box if you don’t want the reverb. The analogies of out of focus or bad framing are good.

[Tim Brown]

Thanks. Good advice. Trying to be camera and sound at the same time (bad mistake) and ended up with very “roomy boom”. Pulled 125 Hz completely and it sounds great.
Cheers

[Larry Herbst]

An ancient thread, but years later this info still helped me. Pulling a handful of frequencies made my very “open” boom sound more like a more closed and workable lav.

The prior comment about “next time get good audio” isn’t helpful, and frankly angered me. Duh. Next time I’ll wrap the entire space in sound blankets, or next time I’ll rewrite the scene to take place in a voiceover booth. Sure, why not? It’s not like we’re not aware there are sound challenges in a space, and we deal with them the best we can, but it’s not because we’re doofuses that we still have difficulties that we’re hoping to ameliorate in post.

I rented a green screen stage that was very “live”, and the furney pads I had didn’t eliminate all the echo. I should have scrubbed the shoot, obviously.

The focus analogy is inappropriate. That’s user error. If you wanted to be accurate, scold someone for shooting under existing light conditions. “If you want a better exposure, next time use lights!” Yeah, we know.

Moving on….