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Jun 24, 2019 - 7:10:01 AM
763 posts since 12/2/2013

Seeing as how all banjo tail pieces perform the same function, how/why do they affect the sound of the banjo?

Jun 24, 2019 - 7:16:47 AM

Alec Cramsie

Canada

286 posts since 2/4/2015

Well, the ones that you can crank down on put more of a break angle on the bridge, directing more vibration to the head.... as I see it

Jun 24, 2019 - 7:28:28 AM

11862 posts since 6/29/2005

According to physicist David Politzer, it's the break angle over the bridge effected by tailpieces that is what alters the sound.  You can read his scholarly paper about that by scrolling down to March 2019 on his site—this also references his April 2014 paper.

http://www.its.caltech.edu/~politzer/

The legendary Presto ones Earl used don't control break angle very much and just "float", but they do shorten the string length between the tailpiece and bridge as opposed to the "no-knot" kind.  There are tailpieces of every conceivable design and weight out there.  I have made brass, aluminum and wood tailpieces, which have radically different lengths, weights, and designs, and I don't find much difference one to the other.  I would tend to agree with David, that the break angle of the strings over the bridge is probably the most important variable.

Edited by - Ken LeVan on 06/24/2019 07:30:47

Jun 24, 2019 - 7:30:13 AM

1122 posts since 2/9/2007

Each length of string between the tailpiece and bridge has its resonant frequencies, and so does the tailpiece itself. All of those are relevant.

So is the string spacing on the tailpiece vs that on the bridge.

Jun 24, 2019 - 7:33:04 AM

753 posts since 12/30/2008

I agree. Break angle is probably the greatest variable. Mass comes into play as well...

Jun 24, 2019 - 7:45:59 AM

763 posts since 12/2/2013

I've been known to get lost in technical discussions that are beyond my ken, so bear with me, please. What is "break angle"? I vaguely understand why a banjo and a guitar sound different, but all things being equal except the bridge, why does that variable only change the tone? I know we are limited by the words/language we use, but why can that variable make a banjo mellow, sweet or snappy or some other combination of these three or more "sounds" (?) we can detect by hearing?

Jun 24, 2019 - 8:06:39 AM

Alec Cramsie

Canada

286 posts since 2/4/2015

The break angle is the angle of the strings after they sit on the bridge, and before they attach to the Banjo. The greater the angle, the more pressure on the bridge.

Jun 24, 2019 - 8:28:05 AM

9843 posts since 6/2/2008

In other words, the angle of the strings at the bridge down to the tailpiece.

I believe tailpieces also contribute to sound by either allowing additional vibrations or helping to dampen them. Strike some tailpieces with your finger and you get a clang, sometimes unpleasant. Deering claims its current tailpiece is acoustically dead. I picked one up at a great price and have to agree. When I tap on it I get more of a dull thud. Installed, of course.

Jun 24, 2019 - 8:34:45 AM
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69444 posts since 5/9/2007

As you adjust the leading edge of the tailpiece down toward the head trebles are increased.
The unadjusted "floating" Presto has a nice balance of lows and highs.It tends to hold itself level to slightly above (1/4"ish) level with no need to change it as high and low tones can be completely adjusted with head tension and bridge weight.

My Cox tailpieces have adjustments in four directions,but I tend to set it where a Presto naturally falls.

Jun 24, 2019 - 8:59:42 AM

763 posts since 12/2/2013

I think I'm starting to get it; my first thought was that the closer the leading edge of the tail piece to the banjo head, the "tighter" the string, which would only effect how high/low the sound. But I think you're saying it also changes the quality of the tone, "snappy" or "mellow"? Is that correct? I'm trying to understand why I love the sound my latest RB4 sounds (with a home made Fults-style tail piece) as opposed to other RB4s I've had as well as SS models. Thanks Steve, your answer is very easy to understand.

Edited by - flyingsquirrelinlay on 06/24/2019 09:00:27

Jun 24, 2019 - 9:37:36 AM
Players Union Member

rudy

USA

14137 posts since 3/27/2004

Break angle is somewhat more complicated than the angle from the bridge top to the tailpiece, the break angle to the front of the bridge is also contributory.  The front break angle isn't normally considered adjustable, so the largest portion of "adjustable angle" is taken care of by tailpiece height above the head.

The front break angle is set by the inter-related sum of head diameter, bridge position on the head, neck mounting height at heel, and back angle of the neck, head tension, and most importantly, bridge height.

Increased break angle generally increases down force on the bridge which greatly effects the vibratory response of the head.  The net result of increased down force is usually a decrease in bass response as well as a increase in high end.  That's usually a goal of "bluegrass" favored tone, but often the opposite in what clawhammer players are looking for.  (Caveat, not always... YMMV...)

The length of the tailpiece has a pronounced effect on tone, again in the ear of the beholder.  Longer tailpiece top plates restrict bridge movement much in the same way that increased down force does, so it's possible to achieve a similar sound by either longer tailpiece length or increased down force.

A longer tailpiece restricts free movement of the bridge in both vertical and horizontal directions, so the side to side rocking movement of the bridge feet (which is another prime force in converting string movement to head excitation) is decreased with the longer tailpiece.

As a "thought experiment" to understand how this works consider a tailpiece that is excessively long and extends within a fraction of an inch of the bridge.  It's pretty easy to visualize how this prevents free movement of the bridge.

Unrestricted bridge movement is so important that many bridges are designed to hold the string ends very close to the tension band, as demonstrated by the popularity of the No Knot tailpiece for clawhammer players.  The shorter bridges are purposefully designed to create as much afterlength of the strings behind the bridge as possible.  Classical violin players obsess about the importance of afterlength, but there's a lot going on there.

Bridge mass also has a small contribution to make in determining tone.  Adding mass (at either end of the instrument) where the strings attach contributes to increased sustain of the notes.  

To sum up, bridge mass, length, overall design, and final height above the head surface all contribute in modifying tone and volume.

Jun 24, 2019 - 10:07:22 AM

5892 posts since 8/28/2013
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Rudy has beaten me to just about everything I was going to add, particularly regarding the break angle at the front of the bridge, which, to me, should always be considered when playing around with bridge heights and choice of tailpiece. A tiny break angle at the front of the bridge weakens the volume.  A good example to illustrate this would be how a guitar sounds when it needs a neck reset. It has lost volume due in large part to a loss of downforce at the bridge saddle. Also, the first thing a piano rebuilder will check is the downforce of the strings over the bridge. Insufficient break angle at the front will ruin the sustain and must be corrected before anything else can be accomplished.

I can only add that there is a limit to just how much downforce can be applied to a banjo bridge. Too much force, whether it be due to a huge break angle or a too-long tailpiece can inhibit bridge and head movement and can tend to kill the sound.

Edited by - G Edward Porgie on 06/24/2019 10:12:49

Jun 24, 2019 - 12:00:21 PM
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763 posts since 12/2/2013

I've also noticed the width of my tail piece is wider than the usual Presto: any significance? Another relative question: is the hardness or softness of the tensioned head a factor in how mellow or snappy the tone? Thanks to all you guys.

Edited by - flyingsquirrelinlay on 06/24/2019 12:02:32

Jun 24, 2019 - 12:32:18 PM

849 posts since 1/9/2012

The March 2019 piece that Ken LeVan mentioned on http://www.its.caltech.edu/~politzer/  lets you hear a 13 degree break angle and a zero degree break angle with the same bridge and tailpiece on the same banjo.

Jun 24, 2019 - 5:29:01 PM

9843 posts since 6/2/2008

quote:
Originally posted by flyingsquirrelinlay

I've also noticed the width of my tail piece is wider than the usual Presto: any significance? Another relative question: is the hardness or softness of the tensioned head a factor in how mellow or snappy the tone? Thanks to all you guys.

 

Tailpiece width supposedly has some effect on sound. That’s the whole idea behind the Price Straight Line tailpiece: Make the leading edge of the tailpiece wide enough that the strings go straight back to the tailpiece instead of angling inward and creating sideways pressure in addition to down pressure.  I used one for a while - I think it’s currently on my archtop. I can’t describe any difference I’ve been able to hear. I’m sure someone like David could take measurements and prove there’s a difference.

And of course head tension - hard, soft, tight, loose - has a big impact on sound.

Edited by - Old Hickory on 06/24/2019 17:30:15

Jun 25, 2019 - 7:21:57 AM

11 posts since 5/27/2019

I'm curious to hear a little more detail on the typical range of string break angle on banjos. When I was building my ukulele banjo recently, I did a fair amount of searching about what it "should" be, and the best I came up with was a general range or 12 to 15 degrees for most movable bridge instruments. Mine worked out to be around 10 degrees as-built and it sounds fine to me, but I must admit that I'm totally new to banjos in general.

But now I see banjos with no-knot tailpieces that must be far far below that range. And just eyeballing photos of banjos in comparison to what I built, it seems like it's probably quite common to have banjos with string break angles less than 12 degrees. So what I thought was a rule doesn't seem to be a rule after all. I realize from the thread that people are selecting tailpieces partly based on the string break angle and the sound quality that imparts, but specifically what angles are people ending up with most often?

Jun 25, 2019 - 12:28:57 PM
Players Union Member

rudy

USA

14137 posts since 3/27/2004

quote:
Originally posted by Uke-alot

I'm curious to hear a little more detail on the typical range of string break angle on banjos. When I was building my ukulele banjo recently, I did a fair amount of searching about what it "should" be, and the best I came up with was a general range or 12 to 15 degrees for most movable bridge instruments. Mine worked out to be around 10 degrees as-built and it sounds fine to me, but I must admit that I'm totally new to banjos in general.

But now I see banjos with no-knot tailpieces that must be far far below that range. And just eyeballing photos of banjos in comparison to what I built, it seems like it's probably quite common to have banjos with string break angles less than 12 degrees. So what I thought was a rule doesn't seem to be a rule after all. I realize from the thread that people are selecting tailpieces partly based on the string break angle and the sound quality that imparts, but specifically what angles are people ending up with most often?


What you've read as a general rule is most likely for instruments that require that break angle to work in conjunction with higher string tension instruments to create energy transfer to a heavily braced and structured soundboard.

What's true with an archtop guitar has little in common with a banjo.  String gauge and tension combined with a relatively inefficient coupling to to a flexible membrane rather than a wood soundboard makes for a entirely different set of requirements.

You don't see tailpiece structures on an archtop guitar, mandolin, violin, etc. because the design of the instrument allows the break angle to be built in.  Banjos, with their flat to slightly concave head profile require a much lower break angle by design, so the adjustable tailpiece provides an option for those looking to change the tone in a way that is more akin to a archtop wooden instrument.

The "break angle" that is more important for banjo is really more the combined front and rear break angle and not simply the angle of the strings behind the bridge.

Again, all this is tempered with the specific sound that someone is looking for, and that has a wide variance.  Very minimal break angle and long string after length as evidenced on banjos with No Knots might be exactly what a clawhammer banjo player is trying to attain, and the opposite of what a bluegrass player might want.

The rule is there is no rule.

Where banjos are concerned you first need to define exactly what you're looking for in tone and then think about the parameters you can change on any given instrument to attain that.

Jun 25, 2019 - 2:00:22 PM

stanger

USA

7201 posts since 9/29/2004

Rudy mentioned this:
"Increased break angle generally increases down force on the bridge which greatly effects the vibratory response of the head. The net result of increased down force is usually a decrease in bass response as well as a increase in high end. That's usually a goal of "bluegrass" favored tone, but often the opposite in what clawhammer players are looking for. (Caveat, not always... YMMV...)"

The down-pressure a tailpiece exerts on the bridge is the most noticeable tone and volume modifier to me.
A No-Knot exerts none at all, and the bridge is driven down into the head only by string pressure.

Once a longer tailpiece adds some down-pressure to the bridge, the volume increases and the tone changes. The tonal change varies from tailpiece to tailpiece.

I found using an Oettinger tailpiece, which have individual fingers, each with it's own adjustment screw, can make one string that sounds less prominent than the others balance out if more pressure is applied to that string.

I've also found some of the longest and/or most massive tailpieces can exert so much pressure on the bridge that they strangle the tone. The bridge has to pump upwards and downwards on the head to vibrate the head. Too much pressure doesn't allow the bridge to go upwards.

The Presto tailpiece is more limber than most, and tends to flex, so it has a damping effect on the string vibration that cuts down on the sustain of the notes. The Presto is non-adjustable, but the down pressure it exerts on the bridge seems to be just the right amount.

It allows the bridge to pump while is still driven into the head for good vibration transmission from string to bridge to head.

I prefer a Kerschner DeLuxe tailpiece overall; they have no string cover, which makes changes faster, and are quite solid with high mass which tends to support sustain. I put just enough down-pressure adustment on them to get the tone I want.

I found that adusting a DeLuxe can change the banjo's tone. On some tunes, I'll lift the pressure off a bit, and on others I'll crank the tailpiece down a bit. The banjo goes slightly out of tune with these changes, but the tone becomes softer or more penetrating.

The length of the blade has a tonal effect too. the Ome Sweetone tailpiece is shorter than others, so it places the pressure on the strings at a different point. It seems to add some crispness to the high strings that a No-Knot can't do. It would probably remove some volume from a very loud banjo too, though I've never tried one for that purpose.
regards,
stanger

Jun 25, 2019 - 2:45:42 PM
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7293 posts since 1/7/2005

Something else to consider is that the break angle at the front of the bridge is increased because most bridges (these days) have a slanted face on the side facing the neck, but is at right angle to the head on the side facing the tailpiece. This arrangement helps equalize the string angle between the front and back sides of the bridge. If the bridge is mounted backwards, as is sometimes done by novices, the tone quality will be affected.

Secondly, the angle of the neck also has a decided effect on tone quality. When the neck slants back from the rim, it increases the string angle at the front of the bridge. On certain banjos where the fretboard overlaps the head, it becomes necessary to raise the strings for clearance over the fretboard. And this is done by reducing the neck angle. I once built a banjo with the overlapped fretboard, and was not particularly pleased with the sound. So I removed the excess fretboard end and re-mounted the neck lower and to the more conventional angle. The sound became noticeably brighter and a bit sharper after the change.

DD

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