Hollow Body Guitar Feedback

[kamlapati]

Most hollow bodies have a resonant frequency around 140-180Hz. My L-5 sure does. The EQ on my Polytone is way better at reducing this, but my experience with Fender amps is that you can't reduce this frequency without hurting your tone. It is also my experience that an EQ pedal really can help a lot. In my case I use an LR Baggs Para DI. OTOH, some drummers and bass players really aren't designed to be playing jazz with a hollow body guitar, and for those guys you'll need a semi-hollow.

[Captain Caravelle]

Most hollow bodies have a resonant frequency around 140-180Hz. My L-5 sure does. The EQ on my Polytone is way better at reducing this, but my experience with Fender amps is that you can't reduce this frequency without hurting your tone. It is also my experience that an EQ pedal really can help a lot. In my case I use an LR Baggs Para DI. OTOH, some drummers and bass players really aren't designed to be playing jazz with a hollow body guitar, and for those guys you'll need a semi-hollow.

You just added a good point that I missed.....
When it comes to using an EQ a parametric is the way to go.
You can zero in on the frequency(s) you're looking for.
As opposed to a graphic which will take other frequencies with it.

[vic]

actually it seems my problems could also be solved through replacing with a semihollow...although I really love the archtop tone..

are there any semihollows with an archtop's tone?

...then get a 335. It has a centre block and one can use it a high volumes with no or little feedback issues.
But first try lifting your amp from the floor.

[kris]

I use Dougplugs on my arch-top...anyway I do not like play to loud on my jazz box.
Attachment 7184

[TieDyedDevil]

Have you tried turning down the bass EQ on the amp?

[Jazz_175]

I also used a Washburn J6, about 10 years ago. It was a nice guitar. I was using the guitar with an AER Compact 60.
I had sometimes feedback problems as well, but not so often.
A Gibson 335, after you turn down the trebles, could be a valid alternative if you want a fully hollow-like tone with a semihollow guitar.

[jorgemg1984]

I have made my own version of those plugs - great way of killing feedback. It changes the sound a lot unplugged - and just a little trough the amp (my two archtops are laminate with buil-in pickups).

Dougs' is way overpriced. I bought some balsa wood and eva foam, a friend of mine designed the plugs on a computer and I went to a CNC store and did it. My luthier painted the balsa ones ebony and both plugs work great - the foam ones are easier to use. Total cost was very cheap, not even 30€ the pair BUT 1) my friend did not charge me the design 2) I was really lucky to find a CNC store that was both cheap and able to do such small work (I think the guy did me a favor actually, no idea why).

[cosmic gumbo]

Hollowbody? What feedback??? Ted didn't have any problems...

[Jonathan0996]

I have a Washburn J-10 Orleans that had outrageous feedback issues, even at moderate volume. I ended up stuffing it with blocks of foam rubber, layering them so they ended up wedged between the back of the guitar and the top, blocking the F-holes. This took some patience, but I got it in there. It not only helped the feedback problem tremendously, but it didn't really affect the plugged in tone.

However, if you're maxing out an 60 watt amp, you'll probably be happier in the long run just getting a semi-hollow guitar. With a fully hollow, fulll-sized archtop, you'll always be managing feedback. Better to focus your attention on the music, in my view.

[ooglybong]

actually it seems my problems could also be solved through replacing with a semihollow...although I really love the archtop tone. Are there any semihollows with an archtop's tone?

Check out the Eastman El Rey line, mostly the I and II models. Not quite exactly sure what to label their construction, but it works.

[mr. beaumont]

I think more along the lines of Kris...right tool for the job. High volume gigs are for semi hollows and solidbodies...

Then again, you know crotchety old me, who thinks people play jazz too loud anyway.

[glasstube]

Hey guys i posted a thread a while back asking about changing my arch top acoustic into an electric...

well it has been done..

Its a late 50's-early 60's Kay/Harmony/Silvertone really haven't figured out the true model yet because my father can't remember what year or where he bought it from...
hopefully someone can tell me.

Anyways it was acoustic and i did work on it and made it electric, the problem is obvious, it has WAY TOO MUCH feedback (unless played at a very low level) even if i do the obvious things to stop it.. headstock toward the amp, setting all sorts of different EQ's etc...

Heres the setup that I am using:

Thats a blackface twin reverb that I am using

I have also heard ways of either taping your F-Holes or stuffing some foam inside them, I have not yet tried but i am guessing that would chop up your tone quite a bit

Let me Know guys that would be a HUUUUGE HEELP!

THANK YOU
-tubes

[jorgemg1984]

I have plugs with EVA and with Ebony. The EVA works best but Ebony is prettier

[fauves]

What kind of volume are we talking about ? I can get pretty high vol with floaters even using pedals. Well into stage vol with a drummer.

What kind of pick up is. It ? Is it wax potted ? Was it new ? Is it wired properly ? Is it grounded properly? A twin is pretty clean and it looks like a hum bucker so I would have the wiring looked at. That's what I would do before I went fooling with f hole plugs.

[jorgemg1984]

Oh yeah, like the Hofner Jazzica covers in ebony - much nicer than all EVA. But then you have to shape the ebony for a good fit, so maybe tricky as a DIY project?

I suppose that the heavier ebony has some arguable tone impact, but I think this is really very minor at most.

Chris

A friend of mine vectorized the f-holes and I went to a CNC center with balsa wood and EVA foam and they did the plugs (I realize my plugs are balsa painted ebony and not ebony)

[kawa]

[Settings]

T1
M6
B1～3(case by case)

[Retroman1969]

What kind of volume are we talking about ? I can get pretty high vol with floaters even using pedals. Well into stage vol with a drummer.

What kind of pick up is. It ? Is it wax potted ? Was it new ? Is it wired properly ? Is it grounded properly? A twin is pretty clean and it looks like a hum bucker so I would have the wiring looked at. That's what I would do before I went fooling with f hole plugs.

I'm leaning towards this...
That setup (I dig it, by the way) really shouldn't feed-back that easily unless conditions are just-so, or there's a problem.
I often practice on a light, carved archtop with a floater plugged into a Fender Princeton Chorus, often cranked pretty hard, and I find it pretty difficult to get it to feed back.
I'm no expert, but I would think that your guitar would be less prone to feedback than mine.
Perhaps a really good luthier could look it over and find a particular cause.

[AZanshin]

I tried placing balloons as suggested from another thread in the F-holes and that has seemed to do the trick.

All I need to do is to try it in a live situation.

[Jazz_175]

G-tube,

This has already been mentioned, but to focus the question:

Are you sure that you are hearing acoustic feedback primarily caused by the guitar body?

It is very possible that the primary location of the feedback is the PU. Some pickups can be remarkably microphonic, and some asian mini-HB floaters have only a token amount of wax inside. This lack of practical potting makes them sometimes very microphonic.

So while the guitar body is part of the feedback loop for certain, movement of the components within the PU can have a very large impact on capturing the body vibrations directly (microphonically) and promoting feedback.

Unfortunately, the best test/solution is an epoxy-potted PU. The Benedetto S6 comes to mind (and has a quirk all it own, but unrelated to feedback), as well as some Kent Armstrong and Bartolini PU's.

Anyway, good luck with the situation. With so many guys offering help here, please let us know what happens.

Chris

I have lots of feedback with my archtop, which has solid spruce top and solid maple back and sides and also maple neck.
I thought the feedback could be produced by a combination of the acoustic qualities of the guitar and the PU.
For example in my case the guitar sounds quite loud in absence of amplification.
And I have a Gibson BJB floating mini-humbucker, which gives a deep, big sound, probably more appropriate for guitars that do not resonate acoustically a lot.
So I was thinking to swap it with the Benedetto S6, which produces perhaps a thinner sound than the Gibson PU, but more suitable to capture the acoustic qualities of the guitar and (hopefully) able to reduce the amount of feedback.
I don't know if this analysis makes sense: what do you think.

[Jazz_175]

If you can get and data on the BJB, then compare the resonant peak to an S6, which is 5.38 KHz (just looked it up).

Chris

I would be curious to know which one is the resonant frequency of the BJB but there does not seem to be much information on this pickup.

[DUBYA R M]

I tried placing balloons as suggested from another thread in the F-holes and that has seemed to do the trick.

All I need to do is to try it in a live situation.

Yeah, that was me with the black balloon trick.
And, yes it does work @ stage volume. You will be able to cut thru the mix
like you were playing a 335!
Just make sure the balloons are inflated enough to cover F-holes completely.

[pingu]

My understanding of pu microphony is that
and unpotted PU can squeal (high pitched )

and that this is a competely different issue to the low pitch
honk you get triggered by the resonant fz of the guitar body
esp when you play a particular note
seems to be 4th ,5th , 6th ,7th fret on the 6th string

Which problem you got squeal or honk ?

[DUBYA R M]

I just don't understand what you mean by a balloon and how you fit it in the f-holes.

I mean a regular blow-up balloon; the same type you see at Kids birthday parties or the helium filled balloons on a string that you can buy at a carnival, or circus and usually wind up floating up in the air. (The balloon, not you)
Anyway, go to a party store (One that sells paper plates and cups, plastic spoons, Happy Birthday napkins, stuff women like to buy for a party their planning)and buy a bag of ROUND black balloons.
Take one out of the bag, stretch it a couple of times, grasp the end that is used to put air in (with your thumb and forefinger, about 2" from the "mouth" of the balloon) and stretch that part a bit too..
Now, with most of the balloon inside the F-hole, you can start to inflate the balloon. I don't think I need to explain to you how to do that!
Once the balloon is inflated to the point that it completely covers the F-hole, (from the inside) tie-off the mouth of the afore mentioned balloon and position the balloon so that the tied-off part is not showing.
Repeat for the other F-hole.
Now you have covered your, F-holes from the inside with a very thin stretched-out rubber-like material, that no-one will notice (unless they get real close and are suspicious guitarists to begin with, and you will have solved that feed-back problem from the F-holes and stabilized the top a little bit also. You basically only added a little AIR to the inside of the guitar. Give it a try, I'm betting you will love it.

[kris]

Dougs Plugs...works OK.

[jorgemg1984]

But he seems to be out of business... and they are very expensive for what they are.

A friend of mine is a graphic designer and designed me f-plugs for my arhctops. I bought some balsa and some EVA foam, found a CNC store who did small jobs, took my friend's files there and done. Total cost was 5€ per plug I think.

They work really well for taming feedback,