Veerstryngh Thynner - Posted - 11/27/2018:  06:21:06

Hi all,

Some time ago I experimented with classical guitar strings and DIY nylon, in an attempt to make my "Morris" tenor banjo sound more like a cello banjo. This didn't work out to satisfaction, ultimately. However, Mike Gregory suggested increasing cubic volume of the pot. If in width is not physically feasible, in depth could logically be considered. And this has stuck in my mind.

My "Morris" has a removable resonator, which opens up the real possibility of adding an extra ring that enlarges cubic volume of its pot. In this manner, cubic volume of the tenor pot can be made correspondent with a cello banjo's, basically. I may also need another tailpiece, a somewhat broader bridge, and another nut, since cello banjo strings are likely to be of heavier gauge.

However, what still remains unclear is as to whether cello banjo necks are longer or shorter than tenor banjo's. Or maybe about similar. Hard to say, at first glance, since optical illusion may be playing in: cello banjo head and pot much larger, in diameter, than tenor's.

My "Morris" is a 23" scale instrument, with a 20-fret neck. Now, my leading thought is that, if 23" scale cello banjos do indeed exist, and the "Morris" 20-fret neck does indeed tally, more or less, with a 23"scale cello banjo's, then my plan would seem to be workable. Replacing tailpiece, bridge, and nut, if necessary, would be acceptable. What I absolutely don't want, though, is putting a saw to the original "Morris" neck.

What I'd like to know is what neck size should be, proportionate to cubic volume of the pot, if artificially increased to be correspondent with cello banjo's. This to decide whether or not my idea has any chance of succeeding. If not, I'll either have to have a cello banjo built, or to make do with some digital trickery.

Veerstryngh Thynner

Edited by - Veerstryngh Thynner on 11/27/2018 07:07:17

G Edward Porgie - Posted - 11/27/2018:  07:03:08

The biggest improvement in tone would actually be an increase in scale length. A cello banjo generally has a scale of 25 or more inches (I believe it's usually more). This allows greater tension on the strings combined with more flexibilty, which is needed for the lower notes of the cello configuration.

While a greater pot volume will help reinforce the low frequencies, you first need to be able to produce those lower frequencies without the added dissonant upper partials. Those dissonant partials will be produced in abundance if the scale is too short, due to the fact that the strings on such a short scale will need to be of a heavier gauge in order to get them to the tensions required and will, therefore, be too stiff. Such short, heavy strings will have poor tone and probably also intonation issues.

The large diameter of the pot on a cello banjo does, in fact, make it appear that the neck is shorter than the tenor banjo's neck, when a cello banjo's is actually longer. I'd suggest looking at the scale length specifications of cello banjos that are currently being manufactured, or measuring one if specs aren't published. If you have access to an actual cello, that would also give you a rough idea of how long the scale should be for those low pitches.

trapdoor2 - Posted - 11/27/2018:  07:05:53

I can tell you that my original S.S. Stewart Cello-Banjo (1895) has a 16" dia pot and a 29" scale length. Yah, it is huge.

I believe the Cello-banjos made later by Gibson (and others) tended towards a little smaller pot dia (14") and guitar-scale lengths. The Gold Tone CEB-4 has a 14" pot and a 24-3/4" scale length.

Veerstryngh Thynner - Posted - 11/27/2018:  07:43:36

George,

Thanks very much for your perspective. It really looks as if having a cello banjo purpose-built is the way to go, doesn't it? That'll be something for the future, though.

Sadly, I don't have access to a real cello banjo. However, I do take your points regarding cello banjo string gauge on tenor banjo seriously. I can see, too, that cello gauge tension would be insufficient on tenor banjo, thus creating all the adverse effects you describe. Intonation issues in particular. However, if still holding on to artificially enlarging cubic volume of the pot, but sticking to just normal tenor banjo strings, could then cello banjo timbre at least be simulated, I wonder?

Mark,

That S.S. Stewart cello banjo of yours must be huge indeed. And 123 years of age - wow!

Do you have any pictures? And what do you know of  your cello's history? Is it American? British?

Please do tell us more!

Veerstryngh Thynner 

Edited by - Veerstryngh Thynner on 11/27/2018 07:58:52

G Edward Porgie - Posted - 11/27/2018:  07:50:12

I would suspect that Marc's Stewart was styled more along cello lines than the Gold Tone, which is probably deliberately made closer to banjo and guitar scales so that modern players would be more motivated to adapt to one. Personally, I'd go for somwhere in between. I've always found the Gold Tone CBs to sound a little thick and not very tuneful or lively, at least in the recordings I've heard. In fact, I rather dislike what I've heard.

Zachary Hoyt - Posted - 11/27/2018:  09:40:30

I have made two cello banjos with 29" scales and one with a 25" scale and I thought I liked the 29" scale lengths better, but as I don't know anything about proper cello banjo technique it's hard to be sure. It was trapdoor2 who first introduced me to the measurements of his Stewart and motivated me to try to make one, once I had a Shopsmith lathe that could turn a 16" rim. The 25" scale on a 16" rim looks a bit more disproportionate than the 29", and the strings had to be a bit heavier.

Zach

Edited by - Zachary Hoyt on 11/27/2018 09:40:49

Veerstryngh Thynner - Posted - 11/27/2018:  11:44:36

Zach, I was hoping that you'd be joining in. You mentioned building cello banjos in some other thread, but I can't remember in which forum.

BTW: what is a Shopsmith lathe?

Veerstryngh Thynner

dlaughery1013 - Posted - 11/27/2018:  13:54:40

Here is a photo of one. Dave L.
art.com/products/p39377920045-...J4wfD_BwE

G Edward Porgie - Posted - 11/27/2018:  14:14:17

quote:

---

Originally posted by Veerstryngh Thynner

However, if still holding on to artificially enlarging cubic volume of the pot, but sticking to just normal tenor banjo strings, could then cello banjo timbre at least be simulated, I wonder?

Veerstryngh Thynner 

---

As I indicated in my earlier comment, a bigger pot will reinforce the sound, but first you have to have a sound to reinforce. I don't think you can get a good sound with a 23 inch scale and the bridge cable sized strings you'll need to get adequate tension to make any sound. Even if you come somewhere near the ballpark, you're never going to see the game. 

It could help some, of course, but I doubt you can do much with that short scale unless you tune a bit higher. If you have a spare rim you could attach to your current banjo temporarily you should definitely try it that way. If you keep the banjo at, perhaps Irish tuning (something which doesn't require the strings to be too huge) then artificially lower the pitch with recording equipment, you may get a better, more cello banjo-like tone.

Zachary Hoyt - Posted - 11/27/2018:  15:08:03

Shopsmith is a US company that makes a machine that transforms into various stationary power tools. They are wildly overpriced new for what they are, but can be had on the used market pretty cheaply. I have one from the early 80s that I use for lathe work, disc sanding and horizontal drilling. The other functions it can perform are already filled by other tools in my shop. Here's a link to an archived thread with a couple of pictures, they only seem to appear if I click on the captions.

Zach

banjohangout.org/archive/341059

Veerstryngh Thynner - Posted - 11/28/2018:  01:42:45

George,

Just to clear away a slight misunderstanding: we are in full agreement that bridge-cable-like cello strings on a short-scale tenor like mine won't work. What I was thinking of, however, when writing my previous post, is enlarging cubic volume of the pot anyway, but with the usual CGDA tenor banjo gauge strings back on. The resulting sound subsequently recorded may then be artificially lowered an octave with, for instance, Audacity.

Enlarging the pot may deepen original tenor banjo sound at least a bit, I reckon. But I think there are also ways of digitally "fattening up" whatever the sound coming out of the Morris, after pot enlargement.

Like my experiment with  classical guitar strings and ordinary nylon wire didn't work out satisfactorily, one with pot enlargement, CGDA tenor banjo strings and digital enhancement may not be successful either, as you rightly point out. But I also believe that the proof of the pudding is in the eating, I still think it worth giving the idea at least a try.

Could you further elucidate on that spare rim please? I don't have one, but it's in envisaging how that would function on the Morris, in practice, that I have some trouble with.

In the meanwhile, thanks very much once again for your continued support. Your expertise helping greatly in laying the foundations for my future digital banjo quartet.

Zack,

Thanks for your photos. That circular saw quite intimidating.

Totally new to banjo building, I'm not familiar with many terms. Heck, I don't even know if I'll be any good at woodworking at all. I wasn't at school anyway. But aged 61 I might give it another shot.

Veerstryngh Thynner

G Edward Porgie - Posted - 11/28/2018:  06:51:08

The extra rim could be useful as a temporary attachment to the bottom of the existing rim to give more volume (I was thinking top of extra rim attached to the bottom of the Morris rim so the rim would be approximately double its original depth) but details of how to attach it temporarily might be difficult, and since you don't have one anyway, there's no real point in suggesting methods to attach one. A length of cardboard tubing the size of the inner diameter of the rim might be placed inside so that it extends past the bottom of the rim, but I don't think cardboard would be a very good material due to it's absorption characteristics, though; it would have a tendency to deaden the tone, I would think.



Another possibility for expanding the pot's volume might be to simply put spacers at the resonator attachments so the resonator stands back a little further than it normally does, but that would be somewhat limited; you could only get so much extra room before the resonator was so far away that the sound became more like that of an openback. Probably worth a try, though.

mike gregory - Posted - 11/28/2018:  08:59:43

If only I could toss tuppence in a wishing well, and wish you were a few thousand miles nearer!

I would love to drop by and work on this with you,

In the words of the world's most famous left-handed, amphibious banjo player

-------------------------------

"Never say die!

say CROAK!"

===================================

trapdoor2 - Posted - 11/28/2018:  13:31:26

quote:

---

Originally posted by Veerstryngh Thynner

George,

Thanks very much for your perspective. It really looks as if having a cello banjo purpose-built is the way to go, doesn't it? That'll be something for the future, though.

Sadly, I don't have access to a real cello banjo. However, I do take your points regarding cello banjo string gauge on tenor banjo seriously. I can see, too, that cello gauge tension would be insufficient on tenor banjo, thus creating all the adverse effects you describe. Intonation issues in particular. However, if still holding on to artificially enlarging cubic volume of the pot, but sticking to just normal tenor banjo strings, could then cello banjo timbre at least be simulated, I wonder?

 

Mark,

That S.S. Stewart cello banjo of yours must be huge indeed. And 123 years of age - wow!

Do you have any pictures? And what do you know of  your cello's history? Is it American? British?

Please do tell us more!

Veerstryngh Thynner 

---

Here's a video I made of the Stewart when I first got it. It was made in Philadelphia, PA, USA (where Stewart had his factory). The scale length isn't all that much bigger than his other orchestral banjos, typical "Orchestra" models ranged from 27-28". It was designed to use standard Cello strings. I use high-tension nylon guitar strings (Savarez). 

VIDEO: S S Stewart Cello Banjo Intro
(click to view)

 

Veerstryngh Thynner - Posted - 12/15/2018:  12:12:34

In the meanwhile, my "Morris" has received brand-new D'Addario phosphorised bronze strings and is truly singing again. Also, maybe, since head tension has been slackened a little.

I'm working on two ideas. The first is to turn the "Morris" into a makeshift "cello" banjo, for studio purposes. But I'd also like to adapt it to Silent Practice instrument, also with an eye on studio recordings, by taking a cue from Sam Farris's Tranjo (not available, alas, as tenor or plectrum).  The first by increasing pot volume; the second by adding a mesh head, a PVC  inner ring and a K & K piëzo element.

I already indicated that I'm not any good at maths, so I'd like your help in establishing the correct amount of "Morris" pot enlargement. I took some measurements that may help to decide present cubic volume - but in centimeters, since metric is what I have been brought up with, not Imperial.

Here goes:

-  head 77.7 cm diameter;

- resonator outside: 34.9 cm diameter;

- resonator inside: 34.7 cm diameter;

- resonator upright rim: ca. 4 cm;

- pot depth outside: 8.7 cm;

- pot depth inside: 7.7 cm.

Furthermore, the removable resonator gave me the idea of a replacement resonator emulating depth and width of cello banjo pot format closest to that of my Morris. So now I wonder if from the measurements provided above depth and width of the alternative "cello" resonator can feasibly be calculated.

Veerstryngh Thynner

mike gregory - Posted - 12/15/2018:  12:42:06

If I was any worse at math, I'd qualify for a DISABLED PARKING sticker.

However: Since the PLECTRUM banjo is VERY close to the same length as a 5- string, you COULD just get  a 5-string TRANJO (TM) and take off the 5th.

As long as the payment is valid, I'm sure Mr. Farris would have no strong objection to his masterful work being subjected to THAT minor a modification.

Or, re-string it with tenor strings, and clamp on a capo to make the scale TENOR length.

Anyway, if you want it under the tree by Christmas, you better hurry.

Or, wait until AFTER, when I've got more free time, and send me a round-trip ticket, and I'll stay with you for a couple weeks, and we'll get 'r done!

Veerstryngh Thynner - Posted - 12/15/2018:  13:56:12

Mike,

Buying a Tranjo is quite an investment. Especially with import charges involved, since I'm (still) living in the UK. So the challenge is to apply some of Sam Farris's innovations to one of my existing banjos. And your suggestion of a cardboard ring gave me that idea.

I don't want my Morris to project but, instead, to "contain", as it were. Like Sam's Tranjo does, with mesh head and PVC ring.  This "contained" sound is then amplified through my recording gear. Simultaneously, having a choice between original and somewhat  enlarged "cello"-like resonators, both detachable, also seems useful, in connection with my future one-man banjo quartet. My Morris potentially to be used as makeshift "cello" banjo as well, with a bit of digital tweaking added.

Veerstryngh Thynner

Edited by - Veerstryngh Thynner on 12/15/2018 14:04:10

G Edward Porgie - Posted - 12/15/2018:  18:25:44

Veerstrinstyngh,



I will try to do some calculations, but I will have to wait a bit, possibly until after Christmas, as I generally detest anything that has to do with numbers and I've been a bit stressed lately as it is.



There is one measurement that I will need that you haven't supplied, though, and that is the inside diameter of the pot.

Veerstryngh Thynner - Posted - 12/16/2018:  05:31:16

Oops!

I'm sure I included inside pot diameter as well, when measuring, but apparently forgot to make a note of that. And I think I'll also need to check up again on outside and inside resonator diameter. If head diameter is 77.7 cm, 34.9 cm diameter for outside resonator can't be right. Next time I'll see the Morris again by the end of January, I expect.

Sorry to hear that you're a bit stressed at the moment. Just take it easy, over the Christmas break. There's no real hurry, so this can easily wait until some other time.

Veerstryngh Thynner

G Edward Porgie - Posted - 12/16/2018:  07:37:54

Funny I didn't notice that discrepancy. Obviously the resonator should be larger than the head.

There are two other measurements that would be worthwhile: because the pot extends into the resonator, part of the resonator volume would also be part of the pot volume. Therefore, it is necessary to know just how deeply the pot extends into the resonator, and the thickness of the the pot walls.

Zachary Hoyt - Posted - 12/16/2018:  07:40:14

I think maybe the head diameter was supposed to be 27.7 cm. I know my handwriting is messy enough that it's easy to mistake a 2 for a 7 sometimes. 27.7 would be slightly under 11" and is a pretty normal size. 77.7 cm would be around 30 inches, which would already be bigger than a cello banjo.
Zach

G Edward Porgie - Posted - 12/16/2018:  13:38:53

At first I really didn't give much thought to the dimensions given, but after a few others' comments and a more thorough examination, some of them are pretty obviously incorrect. That doesn't mean I am not willing to do what to me are fairly simple calculations. I just need corrected measurements to do so.

Veerstryngh Thynner - Posted - 12/22/2018:  05:20:09

George & Zach,

What may have happened is that I mixed up Imperial and metric. Anyway, the measurements provided don't really make sense, obviously, so I guess I'll have to start afresh.

I'll be back on this topic by sometime January. In the meanwhile a Merry Christmas to you all!

Veerstryngh Thynner

Veerstryngh Thynner - Posted - 01/12/2019:  10:41:52

Mike G,

Further to your suggestion to purchase a Tranjo and convert it: yes, I did indeed consider that, at one point, but ultimately decided against it.

Tranjo is a great innovation, no doubt about it. But its design isn't flexible. This, as well as manufacture, wholly automated, to my understanding. So, bass-, cello-, plectrum- and tenor Tranjo, if so desired, would each need extensive reprogramming. As well as an exorbitant hike in retail price.

More sensible - and more attractive, too - would be, to my mind, building from scratch an instrument of different design, yet with qualities similar to Tranjo's. Without any wilful intent whatsoever to infringe on Tranjo design copyright, naturally.

Veerstryngh Thynner

Edited by - Veerstryngh Thynner on 01/12/2019 10:44:19

Veerstryngh Thynner - Posted - 01/12/2019:  11:10:45

George,

Thank you very much for your PM of 11-1-2019 previously and the kindness shown in it 

And in response to this: I haven't yet had the opportunity to return to my earlier theme of enlarging tenor pot cubic volume to cello's equivalent. My Morris tenor not within immediate reach, at the moment of writing. I'll probably see it again by the end of January

My instrument has been stored elsewhere, for the time being. Partly because playing acoustically isn't possible, where I live, and partly because of constrained space. But also due to great upheaval shortly to arrive.

Veerstryngh Thynner