fine-tuning a fix for this audio buzz-ringing

[spiritgumm]

I need some audio fixing advice. I have a dvd recorded from a dvd from a vhs, etc and probably cant get a better copy. The ac3 is low-volume audio on only one channel in a stereo track, but those 2 problems are easy to fix.
The real problem is a weird metallic squeak every couple seconds, which varies in volume. Sounds like a telephone ringing. Get's louder if there's some other noise at the same time, like someone talking. I played a sample in Nero wave editor, and got lucky with the "Band Pass Filter." That has two dials: Lower and Upper. Each goes from 0-24000 hz. If I leave the Lower alone (at 0), and change the Upper to 6600, it eliminates the metallic squeak in the sample - I haven't tried the whole audio yet.
It also eliminates the high tones in general. I'm wondering if there's a way to be more selective? Another filter (which I could see if Nero has)? I could also try Audacity, Goldwave, Cooledit, etc. but wanted advice since I dont know what I'm doing.
Any help is mucho appreciado. Small ac3 attached. dust.ac3

[poisondeathray]

I'm wondering if there's a way to be more selective?

For cool edit you should be able to use spectral view to isolate the ringing , and either delete it or adjust the volume or use some other filter . I did this in soundbooth, but soundbooth & audition are essentially the same thing as cool edit (Adobe bought Cool Edit a few years ago)

I attached an audio sample below and an screenshot of the amplified spectral view just to demonstrate the basic idea of how to select an area. You can see the pattern of the ringing in the low volume channel. This can become tedious very quickly because it's manual marquee selection.... but I don't know of a faster way that is as selective

[spiritgumm]

looks promising, I'll give it a shot. You got rid of all the ringing, too (my attempt did not). Thanks.

[poisondeathray]

You got rid of all the ringing, too (my attempt did not).

There's actually more ringing that the 3 bars , especially when there is speech - there is a 4th "bar" when there is talking, and I reduced the volume of that 4th bar (you can actually finesse it a lot better with frequency filters, to keep more speech if you had time to waste)

open up the wav file I uploaded , normalize it (just to see the spectral view better) , and you will see 4 bars edited when there is speech going on , but only 3 where there isn't any speech - it's not shown clearly in the screenshot above

[spiritgumm]

I tinkered around with some of the FILTERS in Cooledit, but didn't get the right result. I know you used a different program, but how did you lower the volume in certain areas? Use a Notch filter, or something else? I'm assuming I can then apply this to large areas of the audio (some parts dont have these problems).

[poisondeathray]

how did you lower the volume in certain areas?

When you marquee select (i.e. make a highlight box around the area) , you can apply whatever effects or reduce volume to that section specifically, and leave the rest untouched. I actually deleted those section for the most part, not just lower the volume. There should be a function to lower volume or dB in cool edit.

I lowered the volume only in that "box" where there was overlap with the ringing and the speech, all the other sections I deleted (the sections where there were "3 bars" ). The point was to get rid of the residual ringing when there was overlapping speech, but retain as much speech as possible.

There was nothing that I did that used global filtering (ie. on the whole audio) , everything was applied selectively, and that's why it will get very tedious

I'm assuming I can then apply this to large areas of the audio (some parts dont have these problems).

I'm not sure what you mean by this ? All I did here was cut out the ringing as selectively as possible

[spiritgumm]

I've never seen the marquee select feature (I usually select an entire section), so I wasn't sure if the boxes in the jpg were really the effect, or from photoshop to indicate the results of your filtering. My comment about applying to large areas was based on if you were using a filter. But I suppose one could make a very long horizontal box with the marquee setting?

[poisondeathray]

ok i'm not sure if cool edit has it.... In Soundbooth its called "rectangular marquee select tool" and the icon looks like a box. Make sure you are viewing in the SPECTRAL VIEW (vertical axis is in frequency KHz , not dB like the regular waveform)

There are 2 noise patterns, a consistent "phone ringing" in the background (those are the "3 bar" sections) , and also residual "squeeking voice" distortion when they speak, that is slightly different from the "phone ringing"

In the screenshot:
A) Those "3 bars" sometimes occur where there isn't any speech. In the ones labelled "A" they are overlapping with speech

1) I draw a "box" around the area I want. It's set up so both channels are marked at the same time (the box is automatically drawn in the 2nd channel). The one labelled "1" is the marquee selection of the overlap where there is some distortion in the voices.

2) I can change the dB of that "box" or apply any filter to that "box" when it's selected. Nothing else is affected when you marquee select, only the box highlighted

In this screenshot, I've already deleted the other "3 bars" sections , if you compare to the earlier screenshot, there are "gaps" in the spectral graph

But I suppose one could make a very long horizontal box with the marquee setting?

The whole point is NOT to do that, other wise you affect all the other good sections. Since the ringing doesn't occur continuously, you only want to adjust it in those sections where it occurs (ie.. selectively). As you can see in the screenshot there are little "cut out boxes" at time frames where the problems occur only , instead of a long horizontal line that affects the whole duration

[spiritgumm]

The ringing occurs every 3-5 seconds for the first 55 minutes (I'm not sure how much the 4th bar during conversation occurs), so manually fixing each isn't pragmatic for me. What I meant by fine-tuning was to select certain bands, like those boxes, and extend them horizontally. I think Adobe marquee feature is uncommon, and not generally available in other wave editors (at least not in the three I mentioned).
I imagine there's a way to do the same thing with filters or equalizer where you specify and upper and lower limit - rather than simply cutting everything above or below a specific band, yes?

[poisondeathray]

Yes, you can try it - you can see in the screenshot the aberrations occur at ~4k, 6k, 13k, you can try filtering those frequencies. I forget what it's called in cool edit, something like band pass or frequency filter

It's going be tough to fix the "squeeking voice" aberrations using that method because they primarily occur ~8-11k , and if you wipe or filter out those frequencies it's going to sound like garbage

Your original question asked how to be more selective , and that's about as selective as you can get. Since the rings and artifacts don't occur continously, you will be degrading other parts when you select an entire band

[spiritgumm]

hi poisondeathray, I was hoping for a more selective method with the software I mentioned, but I'm still glad you pointed out Soundbooth's marquee feature, of course.
Cool Edit's notch filters can eliminate the ring, but they take alot out of the audio. Instead, I only ran the audio thru the band pass setting in Nero to eliminate the buzz during talking. It lowered the ring a tad, not enough, but it was a good compromise for the xvid (file sharing). What is much worse and unfixable is bits of audio dropout.
I guess I could de-buzz manually, since its frequent only 30 minutes, occasional for next 25; I'd have to fix the resulting volume dips. And the ring would still be there.
Noise analysis will remove the ringing (at least in the sample), but the audio gets that compressed, tinny sound.

[poisondeathray]

sorry , I assumed it was the same , since both soundbooth and audition are based on cool edit pro

what are you doing now? is the buzz the same thing as I call "squeeking voice"

What is much worse and unfixable is bits of audio dropout.

what do you mean by "bits of audio dropout"? there weren't any in that sample? or do you mean caused by the repair? it's hard to fix dropouts

Noise analysis will remove the ringing (at least in the sample), but the audio gets that compressed, tinny sound.

Do you mean noise removal from a noise footprint? Yes, if used too agressively you get that electronic, unnatural voice


I'm not sure what else to suggest. Does goldwave have a marquee selection ? Other audio software does, not just Adobe

[spiritgumm]

From what I could see when I searched, looks like Adobe's marquee feature is "what's new" above and beyond Cool edit.

what are you doing now? is the buzz the same thing as I call "squeeking voice"

Sorry about my terminology. There's the ringing, and the buzz/squeak during dialog. Nero got rid of the buzz/squeak; sounded good enough (you might disagree - in the spectral view, it looked like someone ran over it with a lawn mower).

what do you mean by "bits of audio dropout"?

I should have added parenthetically the dropout occurred elsewhere, not in the sample. Lasts for half-second, couple times a minute for 5-10 minutes. I mentioned it just to put the faint ringing in perspective (which is not nearly as noticeable or annoying as the dropout).

Do you mean noise removal from a noise footprint?

Yep, I meant the noise footprint. Aside from the tinny sound, it didn't always catch the rings in another, larger sample.

As far as I can tell, my version of Goldwave doesnt have a marquee select tool, nor do my versions of the other 3 wave editors (Nero, Cool edit, Audacity). Maybe a new version of Audacity does.