I'm currently 3D printing ERankLuck's awesome Gigameter from Thingiverse, and I plan on adding full working electronics (as a software engineer this is the easy part for me). I've built a pretty decent PKE plus a fully custom proton pack electronics package, in comparison the Gigameter seems much simpler.
But while digging through various forum threads here I found out that the Gigameter isn't actually the silent prop I thought it was! It's just that there's so much background noise in GBII that you usually can't hear it.

So I've spent the last few evenings going down the rabbithole of trying to get this sound effect, and unfortunately nobody seems to have shared it before (I spent a good half hour searching around and couldn't find anything).

Disclaimer: I'm a software engineer, not an audio engineer. I'm sharing what I have in the hopes that maybe it might help someone else, or maybe someone can build upon what I post here.

As far as I can tell, there are four moments in the film where Egon uses the PKE (he's holding it in Oscar's bedroom but unfortunately never actually switches it on).
  • 00:20:35 On the street ("2.5 GEV's on the Gigameter")
  • 00:21:55 After digging the hole ("Looks like you've uncovered an old airshaft!")
  • 00:50:54 In the museum 1 ("We're just doing a routine spook-check")
  • 00:51:08 In the museum 2 ("Whole room's extremely hot, Peter")
The sound itself seems to be made up of two parts. There's the main "warbling" sound, and then there's also the sound of the microphone/ear motors.
To keep things simple I'm only focusing on the warble, because I have no idea how noisy my motor will be once I fit the electronics.

00:20:35: "2.5 GEV's"
This is completely unsuitable because the sound is mixed in with Ray's PKE meter (plus traffic/music).


https://drive.google.com/drive/u/2/fold ... QzNYpfbuJ5

00:21:55 "An old airshaft"
This has dialog over the top, as well as a significant amount of background traffic noise. There's no music though, which helps.


The best option here is actually track 1, which although it looks silent/empty actually has some great audio once you amplify it:

https://drive.google.com/drive/u/2/fold ... FDHHI5-jwX

00:50:54 "Routine Spook Check"
This isn't too bad, there's a lot of dialog/music too but the sound does overlap with Winston's KUD Meter at the start.


https://drive.google.com/drive/u/2/fold ... aeC6SLDbnd

00:51:08 "Extremely Hot"
This also has dialog, but there are short gaps between words.
Unfortunately there's also loud footsteps so I can't even isolate short fragments of this.


https://drive.google.com/drive/u/2/fold ... mNvYcLWvgD

So I've isolated three versions of the audio for this film:
  • TrueHD-Atmos 7.1
  • E-AC3 5.1
  • DTS-HD 7.1
I'm using Audacity and mkvextract.

I extracted the audio files and unfortunately they're mostly the same mix. This is to be expected for a film this old (unlike newer films like "The Martian" where I was able to get crystal clear sound effects off the 7.1 audio).
I'm assuming they started with several source tracks (with/without music and dialog) and then mixed different versions together to create "surround sound".

There does seem to be slightly better isolation in the TrueHD-Atmos 7.1 version so I'll use that.

Each one has:
  • Stereo L/R channel with music and sound effects (no dialog)
  • Mono Center channel with music and dialog
  • Mono Subwoofer channel
  • 2-4 surround channels
The best candidate seems to be the Stereo L/R channel because it has no dialog.
And out of all four clips, 00:21:55 ("An old airshaft") seems to be the most workable.

A bit of messing about with Audacity's Filter Curve EQ tool and I determined the warbling sound sits at around 450Hz.
I isolated this and it mostly removed the background traffic sounds, it's not perfect but it's definitely clearer.

There's a few other slightly different versions of this using various filters:
https://drive.google.com/drive/u/2/fold ... FDHHI5-jwX

When I was finally able to hear it a few times on loop I thought perhaps it might be easier to recreate the sound.
I found a few "sci-fi" sound effects which I thought might be similar, then ran them through some filters but couldn't quite get the right sound.
So I tried generating various 450Hz tones until I found one I liked, then using Audacity filters to recreate one of the waveforms:

I used some Adjustable Fades to try to fade in/out in a less linear fashion, that gets us most of the way there.
Once I had one which sounded decent, I duplicated it a bunch of times and stitched them together.
I then added some random volume changes across clusters of them, so it would be less uniform.

Here's what I ended up with (original movie audio on top, my recreated sounds beneath that):

Original Movie Audio
My Recreated version
(NOTE: Google Drive seems to compress/re-encode the files during playback, so it sounds awful when played via web browser. Probably best to download the WAV and play it back locally if you want to hear the final version).

It's not perfect, it's still lacking randomness, and the warbles don't "glide" as much as the original. Maybe running it through some more filters might help. Not sure.
But, honestly I think that might be good enough for now, I've spent too long on this already.

And when I get time I'm going to upload both the movie version and my recreated version to a soundboard and play it through a small speaker (like I'll use on the final prop). It could be that the movie version is perfectly fine, it just doesn't sound great on headphones. My PKE sounds great even though the source audio sounds like trash on headphones.

Hope this helps someone else, and if you know of other Gigameter scenes in the film that I may have missed, or maybe a better GBII audio mix which might be out there somewhere, please let me know! Alternatively if you're better with audio than I am and feel like you could do a better job of this, please share here.

RedSpecial, jackdoud, Tyrael liked this
UPDATE: OK, looks like I missed a Gigameter scene! 00:59:02 "Will you watch your step!" (the sewer system).
Egon has the Gigameter and switched on. There's almost no background noise except dialog, no music either. The dialog is unfortunately repeated in most of the other tracks, I assume to add the "echo" effect. This would be perfect, even better than the street scene if it worked, except...

I can't hear anything but the Gigameter motors. It's like the audio engineers forgot to add the warbling sound effect, or they left it out for added suspense?

Sounds for this scene are here anyway if anyone wants them:
https://drive.google.com/drive/u/2/fold ... UE5c9oQhRC

Hopefully I haven't missed any other scenes.
Tyrael, jackdoud, Jimsy33 liked this

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