Feedback technique

[Coachz]

Boston's Don't Look Back has a phrase that sounds like feedback with a whammy bar modulating it. https://youtu.be/3VPLOVJ0u94?t=230

Can anyone tell me if that is correct and how they would get the feedback to be on the note that is being sustained. I'm new to feedback and interested in learning techniques of 'controlled feedback'. Thanks for any tips or links.

 

[blues_n_cues]

proximity to speaker,a bit of volume,slight finger vibrato,& when it starts to sustain into harmonic feedback start hitting the whammy bar. that's about it.

 

[Coachz]

so it will feedback at the frequency of the note being sustained ? Thanks for the reply.

 

[blues_n_cues]

so it will feedback at the frequency of the note being sustained ? Thanks for the reply.

actually it's usually an octave above but can be two above or even harmonies of the root.. here's a simple lesson so watch & just experiment-

[ame]http://www.youtube.com/watch?v=luURyH9fzhk[/ame]

 

[Coachz]

i had watched that cool video. thanks, sounds like fun !!

 

[ampmadscientist]

Boston's Don't Look Back has a phrase that sounds like feedback with a whammy bar modulating it. https://youtu.be/3VPLOVJ0u94?t=230

Can anyone tell me if that is correct and how they would get the feedback to be on the note that is being sustained. I'm new to feedback and interested in learning techniques of 'controlled feedback'. Thanks for any tips or links.

There's actually a science to sustain, although complicated physics are involved, the physics are generally ignored...
But some of us study the fine points:

A. Basically, it has a lot to do with a guitar.
A dead sounding guitar won't sustain like that. Some guitars are just worthless for sustain, some sustain like crazy.
You may have 2 identical models, and one might be as dead as a doornail.
The wood, shape, bridge saddles, nut, and pickups are all involved.
In other words, without the right guitar, you get nowhere!

B. Then you need to have an amp with enough gain.
Some amps are based on preamp gain.
(sustain at much lower volumes)
Some need to be cranked up really loud to make the output tubes overdrive.
(sustain at very loud (window shattering) volumes)
Those are the two basic types...

C. Then there are two basic schools...
1. One is to use a preamp before the guitar amp (distortion pedals and clean preamps)
2. The other is to use an amp that has plenty gain, without any preamp pedal. (like a high gain Marshall amp) Amps like Bogner, Boogie, Egnator, etc...there are several.

D. Then there is the particular history behind Boston, and the Guitar Player Mark Scholz...He is an inventor, an engineer for Polaroid, MIT grad, etc...(short version...)
Tom Scholz - Wikipedia, the free encyclopedia
http://www.rockman.fr/Story/Rockman_Story.pdf
At one time, being called the most "cutting edge" guitarist...
He came up with a tiny, battery powered headphone guitar amp called the "Rockman,"
and inside this amp was a high gain preamp, compressor, delay unit, and stereo generator...
which produced this type of sustain and distortion that you hear on Boston Albums.
At the time, it was pretty unique, and groundbreaking concept....You can also use it as a preamp for a guitar rig, etc...etc...
So on Boston Albums, this is basically what you are hearing. Electronics gizmo preamp...

E. And last (short version) There is the guitar playing technique.
Mute all the strings, except the one string that is sustaining.
Otherwise you will just get a lot of UN-controlled ringing and feedback.
It takes some practice...and learning to get it down. There's quite a bit of learning curve to it.

That in a nutshell
As I said there is some complicated physics involved, like in and out of phase signals, distance from the amplifier, and several other factors.
You "can" get an octave, a third, a fifth, or other harmonic of the original note that is played....depending on the technique.
Bands, Guitar players, like Blue Cheer, Hendrix, Bubble Puppy, Iron Butterfly, etc...were the inspiration and pioneers of the technique.
So, you can listen to those players - to get an idea of where this originates, how it developed.

Physics-
The guitar note is played, is amplified, comes out of the speaker, goes thru the air, gets back to the guitar string, and starts a LOOP.
The LOOP is a positive, regenerative feedback loop, that causes the string to be activated from sound waves traveling through the air.
A sympathetic resonance of the guitar and strings.
(That's the short version, folks.)

BUBBLE PUPPY - HOT SMOKE & SASAFRASS - YouTube

Jimi Hendrix Star Spangled Banner Woodstock 1969 ...

[ame="http://www.youtube.com/watch?v=wt3cYpFLJiM"]

▶ 3:52[/ame]

1. Terry Kath "Free Form Guitar" (1969) - YouTube
   

Blue Cheer - Summertime Blues - YouTube

[ame="http://www.youtube.com/watch?v=nU5uDozoSSM"]www.youtube.com/watch?v=nU5uDozoSSM[/ame]


To learn this, you need to listen to your founding fathers.

 

[blues_n_cues]

why complicate things....

fresh strings+gain+volume+vibrato= sustained harmonic feedback

 

[Ghostman]

Definitely has to do with the amp as well. My two heads feedback differently. My Marshall will feedback if I struggle a little bit with it at band volume. My Crate will feedback like crazy. It does have more gain though, not sure if that's the key.

 

[Far Rider]

why complicate things....

fresh strings+gain+volume+vibrato= sustained harmonic feedback

He mentioned Hendrix. All is allowed.

 

[ampmadscientist]

:minions:

He mentioned Hendrix. All is allowed.

Greatest guitar player who ever lived, I would say, IMHO.

 

[mickeydg5]

I thought it had to do with the angle of the dangle. You know scientifically and stuff.

 

[johan.b]

Lots of reverb or delay helps since it increases the possibility of something being in phase..
j

 

[ampmadscientist]

"why complicate things....
fresh strings+gain+volume+vibrato= sustained harmonic feedback"

I under-explained it actually.
To an experienced guitar player, it's almost effortless (for you...).
To a beginner, It's a total mystery.

 

[Coachz]

i'm looking to record some nice feedback in the studio and I might as well get a small amp that gives me plexi or jcm2000 type sounds. What can you recommend please for that ? Preferably a Master Volume amp that i can play loud like a 30 watt or quiet like a 1 watt or .1 watt

 

[ampmadscientist]

i'm looking to record some nice feedback in the studio and I might as well get a small amp that gives me plexi or jcm2000 type sounds. What can you recommend please for that ? Preferably a Master Volume amp that i can play loud like a 30 watt or quiet like a 1 watt or .1 watt

You don't want a master volume.
What you want is to overdrive the output tubes. Master volume spoils that.
Crank the master wide open, crank the preamp wide open.

The most promising ones are
Vox Night Train, Orange Tiny Terror, I'm sure there are others somewhere.
15 watts will really surprise you, volume wise.

The most promising method of getting a good overdrive at a low volume is: A variable magnet speaker...
About FluxTone Guitar Speakers

 

[CRobbins]

Feedback occurs when outputs of a system are "fed back" as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to "feed back" into itself. The notion of 'cause-and-effect' has to be handled carefully when applied to feedback systems:
"Simple causal reasoning about a feedback system is difficult because the first system influences the second and second system influences the first, leading to a circular argument. This makes reasoning based upon cause and effect tricky, and it is necessary to analyze the system as a whole." In this context, the term "feedback" has also been used as an abbreviation for:

• Feedback signal – the conveyance of information fed back from an output, or measurement, to an input, or effector, that affects the system.
• Feedback loop – the closed path made up of the system itself and the path that transmits the feedback about the system from its origin (for example, a sensor) to its destination.

 

[Jethro Rocker]

I use gain, some volume, face the amp, vibrato, a sustaining guitar and go. Also, I don't think Scholz had the Rockman at least for the first album. I recall some music mags at the time talking about his inventions coming up, this of course after the first album. Might have used it on Don't Look Back but with a studio and Marshalls at his disposal, can't Imagine why...

 

[USAPatriot]

I get a slow oscillating feedback on a power chord, A string 7th fret, D string 9th fret. Nowhere else that I know of oscillates. Any ideas why this might be? -Rod-

 

[Coachz]

How is that different from a master volume amp that is wide open?

You don't want a master volume.
What you want is to overdrive the output tubes. Master volume spoils that.
Crank the master wide open, crank the preamp wide open.

The most promising ones are
Vox Night Train, Orange Tiny Terror, I'm sure there are others somewhere.
15 watts will really surprise you, volume wise.

The most promising method of getting a good overdrive at a low volume is: A variable magnet speaker...
About FluxTone Guitar Speakers

 

[Coachz]

The first two boston albums were marshall plexi

I use gain, some volume, face the amp, vibrato, a sustaining guitar and go. Also, I don't think Scholz had the Rockman at least for the first album. I recall some music mags at the time talking about his inventions coming up, this of course after the first album. Might have used it on Don't Look Back but with a studio and Marshalls at his disposal, can't Imagine why...