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 ARCHIVED TOPIC: Weird banjo idea...


Please note this is an archived topic, so it is locked and unable to be replied to. You may, however, start a new topic and refer to this topic with a link: http://www.banjohangout.org/archive/349711

guitarbanjoman - Posted - 01/01/2019:  05:40:29


Ok, let’s think outside the box... but inside the resonator!

What if a banjo drum had two heads, one hidden underneath the other... separated by an airspace, but with an inner “bridge” between the two to transmit vibrations from the top head to the bottom one...?

Would that give us 100% more of the banjoey goodness we love?

Or is this just a dumb idea?

Ponder... discuss!

Happy New Year!

Will

pasdimo - Posted - 01/01/2019:  07:50:02


I had the idea to put another head on the bottom of the rim recently, and the result was interesting. It was just an experiment and I didn't go far away yet because I didn't find a way to tighten this head. Just with the head put like this on the rim the sound was richer, a bit louder but the low register was too much enhanced with too much bass (I play tenor), but I guess it can be improved tightening correctly the second head.
It's very surprising that no maker thought of a rim with two heads (... as far as I know)

DH#52 - Posted - 01/01/2019:  08:07:58


Messing with the ‘soundboard’ of an instrument has some popular support in the classical guitar world with the development of the so-called double top guitar back in the ‘80s, I think. It’s actually 2-3 pieces of wood pressed together (so no space in between, like your banjo head idea), and is/was considered one of the big evolutionary ideas in the development of the guitar.  Aside from experimenting with bracing, this was the first successful attempt to play with the actual top (equivalent to the head on the banjo, right?). 



But back to the banjo...Perhaps two heads closer to one another separated by a really short bridgelike vibrating piece might be something. But heads really only thinly separated maybe.



Steve


Edited by - DH#52 on 01/01/2019 08:11:17

guitarbanjoman - Posted - 01/01/2019:  09:50:17


I got to talking to a classical guitarist a year or two ago, and the latest innovation for guitar tops which he mentioned was this: instead of a spruce or cedar top, they can use a piece ultra-thin carbon fibre with just an ultra-thin wood veneer glued on top for decoration... which is such a thin top that it would almost seem to put the guitar into “banjo territory”...

guitarbanjoman - Posted - 01/01/2019:  10:10:31


...but going back to my original idea... the location of the “bridge” between the two vibrating heads might be an interesting subject for experimentation...

The existing location of the “top” bridge ie the existing bridge that we all have on our banjo heads is about a third of the diameter of the head away from the tailpiece.

This location is determined by at least two things I can think of right now...

- strumming would probably less comfortable if the bridge were in the center of the head

- the banjo neck would probably have to be longer if the bridge were in the center.

But the “inner” bridge, or possibly multiple bridges, could be anyplace we want it to be...

My hypothesis is that putting the “inner” bridge in the very center of the circle would accentuate the longer wave, more bass-y and/or midrange-y tones.

While placing the inner bridge directly underneath the upper bridge would transmit the most powerful vibrations to the lower membrane.

What would happen if there were several small “sound-post” type bridges at different locations between the two membranes? I’m not smart enough to figure that out, maybe you are!

L50EF15 - Posted - 01/01/2019:  10:22:58


This idea reminds me of the Virzi tone producer featured in some Gibson guitars and mandolins. Interesting - very.

Dan Gellert - Posted - 01/01/2019:  10:51:26


quote:

Originally posted by pasdimo

I had the idea to put another head on the bottom of the rim recently, and the result was interesting. It was just an experiment and I didn't go far away yet because I didn't find a way to tighten this head. Just with the head put like this on the rim the sound was richer, a bit louder but the low register was too much enhanced with too much bass (I play tenor), but I guess it can be improved tightening correctly the second head.

It's very surprising that no maker thought of a rim with two heads (... as far as I know)






W.E. Boucher of Baltimore was the first instrument manufacturer to produce banjos, in the 1840's. Some of his earliest banjos had heads on both the back and the front of the rim. 

Alec Cramsie - Posted - 01/01/2019:  12:15:59


From a physics standpoint, you would be doubling the material to excite, but not the surface area, I think that this would make the banjo quieter, kinda like using a mute.
That being said, it sounds like a fun project , don’t let me stop you, and I’d like to hear how it comes out.

guitarbanjoman - Posted - 01/01/2019:  14:27:43


Thanks, Rudy, for introducing me to the Virzi tone producer... new to me and very interesting!



And yes, very similar to what I’ve been thinking about...


Edited by - guitarbanjoman on 01/01/2019 14:39:31

Leslie R - Posted - 01/01/2019:  15:28:00


Cool idea. I would like to see you do it. I think you're going to need to put the inner bridge directly under the upper bridge.
Couple of reasons:
The energy transmitted to the inner bridge well not be sufficient to do much
The intonation is going to be way off if the bridges are offset.

OldNavyGuy - Posted - 01/01/2019:  15:36:12


We would have double the posts on tap tuning, drum dials, and rulers and coins.

Can of worms.

mike gregory - Posted - 01/01/2019:  15:40:19


QUICKEST way to find out:





Get an adjustable tambourine, small enough to fit inside your current banjo.



Take off the jingles.



Make some oval holes to slide the co-rods through.



Yer DONE!



Using tapered wedges above and below the co-rds, move the tambourine closer or farther from the banjo head, mess with the tambourine's head tension and the placement of the interior connective "sound post".



If you really want to thank me for offering this free advice, make a video compilation of various part of the experiment.



And, as to Free Advice in general, I suggest taking a minute or 3 to listen to MY hero, Alan Sherman.



 



guitarbanjoman - Posted - 01/01/2019:  15:52:53


Using the Virzi idea, but adapting it to the banjo... what if the “underneath” membrane were not held down with brackets, but instead it was a circular plastic membrane attached very tightly to some sort of rigid frame...

Perhaps the attachment of the membrane to the frame could be done by heating up the plastic with a hair dryer, the same way as those plastic storm windows you can mount inside your regular window...

Then the plastic membrane disk could be suspended underneath the upper bridge in much the same way as the Virzi “plates”... this might create some additional high frequency overtones much as described by Lloyd Loar in this article...

siminoff.net/virzi-tone-background/

Thus a banjo with two membranes could be set up so that one would act as a “woofer” and the other a “tweeter”...???

Would this be a desirable objective???

I don’t know!

What do you think?

guitarbanjoman - Posted - 01/01/2019:  16:00:04


PS Thanks everybody for your Good Advice!

mike gregory - Posted - 01/01/2019:  16:27:11




"You're welcome"



-C. Columbus-

L50EF15 - Posted - 01/01/2019:  17:30:31


This seems quite feasible; a frame (something like a thinner version of a tone ring, perhaps) with its own head shrunk onto it.

Hmm. Now I am wondering if an actual Virzi has ever been used in a banjo.

L50EF15 - Posted - 01/01/2019:  17:35:10


Ah ha! I should have known that Eddy had dispensed wisdom on this topic at some point:



banjohangout.org/archive/169801

Meles_Meles - Posted - 01/01/2019:  20:41:36


It strikes me that what you're thinking about would be subject to the same physics that distinguish speaker cabinets such as the ported and bass-reflex varieties. Simply sealing off the internal air space would give the head more 'spring' that a single-mebrane head, amplifying the lows and acting as an RF choke for the higher notes. 'Porting' the inner head, say with a single central opening, would only further muffle the resulting sound, because the player's tummy would be blocking the porthole. Perhaps the solution to this would be a ring of smaller portholes in the inner head, around the circumference of the inner head. This would leave some of them open (depending on how the player held his/her instrument), allowing the higher frequencies to ring out without boosting the bass quite so much. (Think of all those modern guitars and ukuleles with a side port and smaller soundhole.)



Granted all that, it would be interesting to hear what tonal difference  is produced by altering the distance between the main (original) and inner heads...


Edited by - Meles_Meles on 01/01/2019 20:43:06

guitarbanjoman - Posted - 01/02/2019:  20:10:43


Hmm... interesting thoughts, thanks...

Maybe I’ll just try an experiment... remove the resonator of my banjo and cover the drum with a piece of that plastic which shrinks when you heat it with a hairdryer...then put the resonator back on again making sure the plastic is still able to vibrate without touching the resonator...

guitarbanjoman - Posted - 01/08/2019:  15:35:53


A somewhat disappointing experiment today.

I bought a five dollar sheet of that storm-window-shrinking plastic and managed to attach it to the back of the wooden rim with painters tape.

I used a hairdryer on the plastic and shrank it until it seemed it might break...? Thats the problem, since ive never done i have no idea about this plastic...

Anyway, the difference in tone was rather minimal... in fact it reminded me of an old trick that ive sometimes used with El Cheapo banjos... get a soft plastic bag from the dry cleaners and stuff it in the resonator... ever tried that one? Its elusive to describe, but somehow the tone is just better in some way... placebo effect? Likely!

Well, today was sorta like that...

Will

guitarbanjoman - Posted - 01/08/2019:  16:21:12


quote:

Originally posted by guitarbanjoman

A somewhat disappointing experiment today.



I bought a five dollar sheet of that storm-window-shrinking plastic and managed to attach it to the back of the wooden rim with painters tape.



I used a hairdryer on the plastic and shrank it until it seemed it might break...? Thats the problem, since ive never done this i have no idea about this plastic...



Anyway, the difference in tone was rather minimal... in fact it reminded me of an old trick that ive sometimes used with El Cheapo banjos... get a soft plastic bag from the dry cleaners and stuff it in the drum... ever tried that one? Its elusive to describe, but somehow the tone is just better in some way... placebo effect? Likely!



Well, today was sorta like that...



Will






 

G Edward Porgie - Posted - 01/10/2019:  12:45:57


Tomorrow is another day, so don't give up right away. You may not have gotten the optimum set up the first time. Hundreds of inventions have gone through a lengthy development process.



I do believe that any change you get, no matter the configuration, will be subtle, and may not be exactly what you are looking for. Many Virzi devices have been removed from old mandolins simply because they produced a tone that bluegrass players didn't particularly like, though others such as Lloyd Loar did.



I'm sure that there have been many experiments with extra heads, resonator enhancements, and almost anything else short of dynamite filled pots that have been tried over the decades. It's too bad that failures are not usually mentioned, as we can all learn a lot by what doesn't work, probably just as much as we learn from what does. Keep at it, and please relate your results, even the bad ones.

Veerstryngh Thynner - Posted - 01/11/2019:  04:13:09


Will,



What happens time and anon is that part-aspects of a theme are being worked on separately, in various parts of the globe. Then somebody else comes along, joins the dots - and a great new invention is born. This, in a nutshell, how telephone and, I think, TV arrived.



Something similar seems to be happening in this thread. My grey cells, too, have been busy, for quite a while now, figuring out some workable way of fitting in two heads. And this started with Sam Farris's Silent Practice Tranjo.



What I have been after isn't enhancing volume, though, but reducing it, rather. A paper-thin layer of perspex between me and my nearest neighbour. Thus, playing and recording acoustically is out of the question. And so Silent Practice Tranjo seemed a godsend, at first - until I discovered that it comes with five strings only (I'm on tenor banjo). Bother! But SPT's mesh head and PVC ring got me thinking.



The sole way of playing noiselessly I previously saw was switching to flat-body electric. Which I did, for a while. However, giving my electric tenor guitar a tenor banjo voice, digitally, proved a dead end, after lots of experimenting. Furthermore, I definitely don't want head and ring built into my electric tenor. Tenor guitars hard to come by, in Europe, so I'd rather like to keep mine in its present glory. So, if adapting an existing instrument isn't an option, a wholly new one needs to be built from scratch. Which, to cut a long story short, is where my thoughts are presently heading.



A banjo builder I'm not. To get the work done, I'll need a professional luthier. But due to costs to be involved, a prototype built to my specifications must wait until 2020 or 2021 at least. Financial resources presently availabe set aside for priorities presently much more pressing. What I want to do, though, is blueprinting my plan, since I feel I'm really on to something. And the gist is this.



My initial direction was a solid body electric instrument with in-built tone ring/head and retractable neck, easily to be converted from cello banjo to tenor banjo, somehow. My reasoning that with a cello banjo ring/head fitted in, cello head circumference and diameter might be reduced to tenor banjo size by pushing up a felt-padded dampener ring or membrane up against the main head's underside. Or even mesh rested against the main standard head. But this set-up caused too many headaches in association: double bridges, issues with bridge positioning relative to tenor and cello settings and with tailpiece placement, and so on. Too many loose bits and constructional weaknesses popping up along the way. So viability went out of the window and a rethink was on.



Of lately, however, I have hit on a plan that involves standard head (for public performance) and mesh head (for practising and recording purposes) to be alternated to requirement. Within one and the same instrument frame. I'd like to keep my cards close to my chest, for the time being, but I'll shortly be off to the drawing board again.



Ta.



Veerstryngh Thynner

bluegrassjunkie - Posted - 01/11/2019:  06:12:58


Might be of interest...
BanjoMate Tone Enhancer

Mounts on inside surface of resonator

littlemountainmusic.com/banjom...hancer-1/


guitarbanjoman - Posted - 01/11/2019:  06:30:10


Thanks everyone for some great contributions to the thread... what the heck, i think I’ll just try that BanjoMate tone enhancer for now, while I’m still trying to figure out how to add that second head!

Veerstryngh Thynner - Posted - 02/10/2019:  03:16:06


Will,



I believe that Rudy built a banjo around a double-headed handdrum.



Veerstryngh Thynner

ProperNoun - Posted - 02/10/2019:  04:47:41


quote:

Originally posted by guitarbanjoman

...but going back to my original idea... the location of the “bridge” between the two vibrating heads might be an interesting subject for experimentation...



The existing location of the “top” bridge ie the existing bridge that we all have on our banjo heads is about a third of the diameter of the head away from the tailpiece.



This location is determined by at least two things I can think of right now...



- strumming would probably less comfortable if the bridge were in the center of the head



- the banjo neck would probably have to be longer if the bridge were in the center.



But the “inner” bridge, or possibly multiple bridges, could be anyplace we want it to be...



My hypothesis is that putting the “inner” bridge in the very center of the circle would accentuate the longer wave, more bass-y and/or midrange-y tones.



While placing the inner bridge directly underneath the upper bridge would transmit the most powerful vibrations to the lower membrane.



What would happen if there were several small “sound-post” type bridges at different locations between the two membranes? I’m not smart enough to figure that out, maybe you are!






This is similar to the concept of a violin soundpost. 

It's basically a way of doubling the sound board because in a violin, the back plate isn't a resonator as much as in a guitar.

It's literally a secondary soundboard because the sound post transmits all the residual vibrations the front plate wouldn't have been able to absorb. 



Difference though with a banjo is that you'd create a sealed vacuum as well as producing a secondary sound board. 

This is why bass drums are sealed. Sealed vacuum being pressurized upon a strike creates really loud bass tones.

Same as when you smack a bag of potato chips. The pressure crashing up against the walls of the back creates this bassy thump.   



This would be obscured slightly by a sound post as you would also get string vibration on the second vellum. I think you'd wind up with a muddy sound because of this.



They way to solved this is to put two holes on either side of the bridge on the top vellum (Like F-Holes)



You can reinforce the holes of that vellum with some metal rings, that way you don't loose pressure on those parts of the vellum as uneven head tension would cause other issues. 



Another likely safer way to do this is to use a 10" top head, and then install a 12" head on a banjo resonator of the banjo. 

Than install your sound post from the bridge to the resonator's drum head. The trick will be tensioning the head on the resonator, but you could use a tensioning system like that on the Fire Fly banjo.  


Edited by - ProperNoun on 02/10/2019 04:50:59

banjobard - Posted - 05/23/2019:  08:11:18


I saw a bho member selling a twin head some years ago. They didn't like it, too heavy and muffling

But in the world of drums, I've seen it in snares, and hedwitschak offers Bodhrans with a 'twin skin' lamination - bodhranmaker.eu/en/fireball

banjobard - Posted - 05/23/2019:  08:15:53


I also think it'd be fascinating to make a heavy central 'dot' on a banjo head like exists in tablas, made of?iron filings and rice powder?. That dot gives them the capability of being highly tonal drums instead of, say, bongos.

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