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Anthony Jackson Overdubbing a Bass Line

#9
jerry said:
"Bring the flanger out" I dug that, the Ray Russell stuff is killer.
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OT have you ever seen real flanging done in an analog studio done with two two track machines? I saw it done once



As an audio effect, a listener hears a "drainpipe" or "swoosh" or "jet plane" sweeping effect as shifting sum-and-difference harmonics are created analogous to use of a variable notch filter. The term "flanging" comes from one of the early methods of producing the effect. The finished music track is recorded simultaneously to two matching tape machines, then replayed with both decks in sync. The output from the two recorders is mixed to a third recorder. The engineer slows down one playback recorder by lightly pressing a finger on the flange (rim) of the supply reel. The "drainpipe" or subtle "swoosh" 'flange flango' effect "sweeps" in one direction, and the playback of that recorder remains slightly behind the other when the finger is removed. By pressing a finger on the flange of the other deck, the effect sweeps back in the other direction as the decks progress towards being in sync. The Beatles' producer George Martin disputed this "reel flange" source, attributing the term to himself and John Lennon instead.[1][2]

Flanging - Wikipedia
 
#10
bobyoung53 said:
as shifting sum-and-difference harmonics are created analogous to use of a variable notch filter.
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Captain Pedantic would like to point out that that Wikipedia article is incorrect: Tape flanging most definitely does not create "sum-and-difference" harmonics. Moreover, it literally does create multiple moving peaks & dips (aka, notches) in the frequency spectrum, so it's more than just "analogous" to a variable notch filter...which btw would not create "sum-and-difference harmonics" either. Crap editing on that Wiki entry. :::smh:::
 
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#11
Bob_Ross said:
Captain Pedantic would like to point out that that Wikipedia article is incorrect: Tape flanging most definitely does not create "sum-and-difference" harmonics. Moreover, it literally does create multiple moving peaks & dips (aka, notches) in the frequency spectrum, so it's more than just "analogous" to a variable notch filter...which btw would not create "sum-and-difference harmonics" either. Crap editing on that Wiki entry. :::smh:::
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Interesting, I really didn't read it closely but I'm probably not technically informed enough to know why 'sum-and-difference' (micro) harmonics is not correct though and why they're not the same as 'peaks & dips', they sound like the same thing to me. All I know is it's really cool to watch and I feel honored to have seen it back in the day. :laugh:
 
#12
bobyoung53 said:
I'm probably not technically informed enough to know why 'sum-and-difference' (micro) harmonics is not correct though and why they're not the same as 'peaks & dips', they sound like the same thing to me.
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It's all about the maths :)

"Harmonics" are by definition multiples of the fundamental frequency. So, for example, if the fundamental is 100Hz, the naturally occurring harmonics will be at 200Hz (100Hz x2), 300Hz (100Hz x3), 400Hz (100Hz x4), etc. Note that 100Hz + 200Hz + 300Hz + 400Hz when heard simultaneously all sound quite consonant together, because they represent the natural harmonic series; they're heard as a very rich and solid 100Hz tone reinforced by an octave up, and octave & a perfect fifth up, and two octaves up.

"Sum & Difference" is by definition another different mathematical process that literally adds and subtracts a frequency to/from the fundamental (and all its associated harmonics). Note that Sum & Difference does not occur in nature; it's an electronic process (most commonly associated with Ring Modulators). So, for example, if you took that above-mentioned very rich and solid 100Hz tone with its first few harmonics and ring modulated it with a 90Hz tone, the results will be 10Hz (100Hz minus 90Hz) and 190Hz (100Hz plus 90Hz)...but also 110Hz (200Hz minus 90Hz), 290Hz (200Hz plus 90Hz), 210Hz (200Hz minus 90Hz), 390Hz (300Hz plus 90Hz), etc. because you're getting the Sum & Difference of all the original harmonics as well. And 10Hz + 190Hz +110Hz +290Hz + 210Hz + 390Hz will most definitely not sound "very rich and solid" because none of those frequencies are multiples of one another; they're not harmonically related. Instead, that tone cluster will sound clangourous, metallic, robotic, synthetic.

The peaks & dips in the frequency response caused by tape flanging don't change the mathematic relationships between fundamentals and their harmonics; they simply affect the relative amplitudes of all those frequencies.
 
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#13
I know what harmonics are and how to calculate them mathematically.

Here's a good example of it: 1959 Toni Fisher, very metallic and robotic sounding to me, I think they just left the second tape slightly behind all the way through, no, it's explained in the article.

"The effect that Larry Levine or uncle Leo discovered and used in The Big Hurt was positive flanging. The dry and delayed signals were combined in phase. With very short time differences between the two decks, cancellations occurred at notches in the higher frequencies, producing the jet plane effect."

According to this article it is partially the Doppler effect which I assume is sum & difference as the two decks rarely ran at the exact same speed and a tiny difference was enough in addition to the phase difference.

Flanging - Studio Electronics




Here's also a good primer that explains how to do it with one two track and a multitrack


An 8 Step How-to on Analog Tape Flange
 
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