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Author Topic: Strange looking wave forms?  (Read 1880 times)

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Offline down2earthlandscaper

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Strange looking wave forms?
« on: December 24, 2018, 12:12:28 AM »
These screenshots are of 4 songs from the first set of this show. Two of the waveforms look normal and the other two look strange (like a comb, so is this comb filtering?)  Curious because the mic positioning didn't change at all between songs, nor any of the settings on anything. Why would some songs seem "normal" and others have the weird "comb" look?

Here is the show for reference in case any anomalies can be heard as well as seen on the waveforms.

https://archive.org/details/Clinton.Fearon.2018-12-09.AKGc568eb.mixpre6.flac24
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Offline morst

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Re: Strange looking wave forms?
« Reply #1 on: December 24, 2018, 02:38:43 AM »
Comb filtering is something you might be able to see on a spectrum analyzer graph of amplitude vs frequency, but not these "amplitude vs time" charts.


I'm checking the tracks, and I think the spikes you are seeing are called Loud Kick Drum.
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Offline chk

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Re: Strange looking wave forms?
« Reply #2 on: December 24, 2018, 08:25:41 AM »
It’s just differences in the music. Those look totally normal.  Probably some combination of the bass and drum beat. I believe if you had an issue with comb filtering it would probably be a consistent issue on the recording (provided the mics and/or sound source didn’t change positions) and you wouldn’t see it on a wave form that is zoomed out to the degree those are.

Offline opsopcopolis

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Re: Strange looking wave forms?
« Reply #3 on: December 24, 2018, 09:31:01 AM »
As others have said, that's totally normal. Just regular peaks in the music
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Offline down2earthlandscaper

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Re: Strange looking wave forms?
« Reply #4 on: December 24, 2018, 01:14:01 PM »
Thanks everybody.
Mics: CA-14(cards & omnis) and CA-11(cards & omnis) ; AT853's(cards, hypers, mini shotguns); Busman BSC-1 (cards, hypers, omnis)
Nakamichi CM300's (CP-1,2,3,4) Nakamichi CM700's (cards, omnis)
Tascam PE-120's (cards, omnis) Peluso CEMC-6 (cards and subcards)
DPA 4061's DPA 4022's; AKG 480 ck61 and ck63; Naiant AKG Active Cables
Preamps: CA-9100; Naiant Tinybox (12v/48v + PIP 8V); Naiant Littlebox;
DPA MPS6030; Sound Device Mix Pre-D
Decks: Mixpre 10T and 6; Roland R-07; Marantz PMD620; Sony PCM M10; Edirol R-4; Zoom H6; Marantz PMD-661; Sound Devices 722

Offline u2_fly_2

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Re: Strange looking wave forms?
« Reply #5 on: March 18, 2019, 01:18:42 PM »
Yes, just a change of "beat" in the songs...more drums.
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Offline Ben Turnbull

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Re: Strange looking wave forms?
« Reply #6 on: April 07, 2019, 11:35:39 AM »
All that and possibly the LMA player's graphic limitation on width, which would "stretch" shorter files, exposing more detail, and "scrunch" longer files into the same space and that makes them denser.  Just a SWAG on my part, but might be close.
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