guitar feedback

[Mark Hammer]

1) A big part of Frank Zappa's sound was sheer volume.  Seriously loud.  There WAS a Barcus-Berry Hot Dot pickup in one or more of his guitars bit it was installed in the neck near the neck joint.  The purpose was more to get the neck scrapings that gave him that quasi-acoustic sound, rather than for feedback purposes, from my understanding.  I had the pleasure to have seen him perform on at least 8 or 9 occasions and met the man (although gear talk was not part of it).  His stage tone was always, always killer.  You could tell how much fun he was having by how much his pony-tail swayed as he played.

2) There is a distinction between shaking the body and sustaining the strings that way, and feedback which is not sustain-related.  When some people talk about "feedback and sustain", what they really mean is "I want something that will make my strings ring longer, the way they do when my amp is turned up".  In that instance, one expects any contribution of the amp volume to shake the guitar body in sympathy with whatever you've plucked, and just keep it going longer.  This is different than screechy feedback which can be a product of pickup microphonics and simply standing too close to the amp.  That is not to say that body-shaking feedback is always at the note fundamental, but that it is harmonically related to the notes played.  In contrast, the other type of feedback you can get just by standing near the amp may not have any harmonic relationship to notes played, can vary frequency just by pointing differently, and doesn't even require notes to be played for that matter.

3) I have a little battery-powered amp that I built into a rather flat plastic enclosure.  When I stick that between my belly and the back of the guitar, two things happen: I get a tummy ache, but the guitar achieves feedback-sustain similar to loud volumes with ease at a volume you can talk over.  Note that this involves shaking the body, since it is nowhere near the strings themselves.  Now, shaking the body DOES end up shaking the strings, but the body does not have the bandwidth that strings do, so the nice part is that it tends to sustain the fundamental, not harmonics.  If a person wants to have sustain which is more easily energized, one possibility is to route an area big enough for a small speaker behind/under the bridge and install a small amp there.

4) If it's the other type of feedback you want, just wind your own pickups, making sure to keep the windings loose and DON'T pot it.  I've made a few of those and those suckers will feed back if you so much as look at them.

[Paul Marossy]

It's been a large part of my live sound ever since.

Care to share any of your secrets?  :wink:

[Doug_H]

[;lkj

[Satch12879]

1) eBow

2) +1 on the Fernandes Sustainer.  Steve Vai, another master of feedback, uses this thing constantly.  Check out his last couple of live albums and the Live in London DVD if you want to check it out.

[Johan]

phase or out of phase doesnt matter..its volume/ gain that matters....at 1kHZ the sound will travel about 1feet/millisecont..taking a half step back or forward will place you  in ( or take you away from )the same position in comparison to the phase of the amp as an in phase/out of phase amp....Mark Hammer is right..geting instant feedback is a matter of volume/gain...if any particular amps are particulary good for feedback, it's probably becouse they have a lot of the fundametal and second order harmonic distortion and not too much of odd order overtones ( wich would work against it..)

Johan

[Paul Marossy]

Hmmm.... that must be how Vai gets those sounds on "The Ultra Zone"....

[Marcos - Munky]

Hey David, do you have the article about the piezo pickup in your PC? Could you send it to me? And Eric, I'm interested in your secrets too .

[Ben N]

Is the fernandes a mechanical transucer (like a speaker)?  It looks like a pickup, so I was wondering if maybe it excites the string mechanicaly.  Also, going with what Mark was saying, would mounting a transducer in closer proximity to the strings--say, in the trem block of a Strat or under the bridge plate of a Tele--be more efficient in causing sustain/feedback?

BTW, I seem to recall a discussion a while back (maybe in the archives?) about possible used for the Soundbug that touched on using it as a sustainer, like the sustainiac.  I wonder if anyone has tried it.

Ben

[coreybox]

John Egerton


looking forward to seeing how it turns out for you. Please post as soon as you can regarding how it works. it seems to be pretty promising, that is if it works right. thanks.

corey

[David]

Hey David, do you have the article about the piezo pickup in your PC? Could you send it to me? And Eric, I'm interested in your secrets too .

Munky:

I doubt I have it in electronic form, but I'll try to hunt down a link to some articles on it.  It's really not rocket science, but for once something cheap worked very well.

[DDD]

Hi all,
first of all I have to say that Sustainiac sustainers made by Maniac Music are very impressive from the point of view of an engineer. Also, due to the good engineering they IMO should have the best sound abilities.
In opposite, there are no impressive Sutainiac sound clips on the Net. What's the matter?
As far as I know Maniac Music people work hard and they have no time to make quality records. They are quite satisfied with the samples recorded by occasional or amateur players. But, even without massive advertisement they have more than enough clients\orders.
I venture to recommend to visit they FAQ at
http://www.sustainiac.com/faq.htm.
There one can get a lot of info - theoretical as well as practical.

[Ge_Whiz]

A less embarrassing source of a vibrating motor might be an old mobile phone with a vibrating call alarm...

[Ansil]

Something I've been considering is putting a speaker and a piezo PU in a (well) tuned autoharp. I think by using a few stomp box kinds of things and a few synth circuits (like a VCA) you could get some pretty useful feedback sounds at somewhat low volume. I think there would need to be a lot of experimentation though.

From my experience the most important thing to get feedback in a loud situation is the distance in front of the speaker. When I used to play out (in the height of my Townshend, Hedrix, Belew noise style) I would find out where different notes would happen and mark the stage for these different notes, a la Belew.

It's worth it to try experimenting hitting a note, facing the amp, and slowly move further away from your amp (or closer to it) to find the distance where that note will feedback for you -- diferent notes will have different distances in most cases. Note: this "practice" session will not make you a lot of friends with your neighbors or room-mates.

John

good idea i took apart an autoharp and built it in a hammond D box.  it worked lovely problem though is that the thing won't shut up ie notes run toegther however the rough paint brush is still on there.


to everyone else the basics of this is.

the guitars output is stolen from the pickup selector and fed to this little amp.  the output feeds a speaker that due to all pickups being slightly microphonic will induce some sort of feedback/sustain.    take a pair of headphones and plug your guitar into a splitter run your guitar into a headphone equiped amp and a regular amp.  place the headphone speaker over your pickups

if you can get a usable sound then you should be able to control it into breaking away into feedback. it was done originally on a little terminator guitar that my brother had gotten i slammed it against the wall and the speaker came on while being plugged in to the marshall i believe is the amp i was using at the time.  

anyway  it started to swell and drone and do all sorts of fun stuff.  i imediately put in a switch and a modified vol/tone for the control of this thing.  worked better than i could ever dream.

i got bored oneday and put a little speaker behind my pickup that was bad microphonic and i was going to can anyway. and i dropped it in a guitar.  i thought it was quite humerous that i could get it going and the magnet didnt' interfear with normal playing.

i have some clips of this thing in action but it is still on cassette tape.



hope fully this clears up some questions.

also i didint' do the layout in a hurry.  the package from radioshack actually said piezo speaker. but its just plastic.  instead of a paper cone.

seems to do better IMHO   YMMV.

as always though there are some things to consider too.  type of guitar overall volume levels that have already been mentioned and where you hold the guitar.  it still acts like a helping hand in feedback it isn't like an ebow it doesnt' do it at any level it just helps it along.  another sustain trick is to take the vibrating motors out of old larger pagers. and bury it in one of the horns of a strat. and hook up a small battery pack to it. if you get the speed right you can get it to drive the whole body into making your guitar a really resonant beast however it is a little noisy at times. probally easier to get one of those little vibrating minieggs and drill a hole in the guitar and epoxy it and use the speed control to its advantage.

[Marcos - Munky]

Anybody knows a simple splitter schematic?

[petemoore]

I belive theres something at GEO...
 Also the first half of the 'Splitter=blend" at ROG or Homewrecker

[Marcos - Munky]

Thanks. I will take a look.

[Ben N]

Boils down to a "Smokey" under your strings.

[Ansil]

i guess it does. boil down to that.. being as i had never played or even heard of the smokey amps when i first started doing this i couldnt' tell you.

[Eric H]

And Eric, I'm interested in your secrets too .

I use a very simple setup that won't work on many rigs. I run a 4" heavy-duty speaker that is wired in parallel with the main speaker in my tube amp. The speaker is attached to the back of the headstock with a  large magnet (magnet to magnet). I use it  primarily to get subtle swells, feedback, and amazing sustain at a moderate volume and with clean tone (like Doug described).
You can hear some of this by listening to this clip from around the 2 minute mark:
http://home.nethere.net/ehensel/files/another%20day%20at%20the%20mine.mp3

[Marcos - Munky]

I will give a try to it in a few days.