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jshelton5040

Posts: 1500
Joined: Jan. 17 2005

ports

I have a customer who wants a blanca with a port. I am pretty much ambivalent about the use of ports but in the current lousy economy I'll do pretty much anything a customer wants and adding a port when the guitar is being built is certainly no big deal. Any thoughts on the ideal (standard) size port?

On another topic:
I recently asked opinions on how to build a guitar with "booming" bass. We have started two double body classic guitars which I hope will have the "booming" bass requested by two different customers. I plan to make the bodies a little deeper, the cedar tops a little thinner, the sound holes a little smaller and the fan bracing a little stiffer above the bridge and dramatically tapered below the bridge.

The other interesting experiment that we'll be doing this season is a Paulino Bernabe inspired blanca with minimal fan bracing and a staged top. I'll post pictures of the interior at the appropriate time.

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John Shelton - www.sheltonfarrettaguitars.com

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 21 2014 23:50:45

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: ports (in reply to jshelton5040)

The size of the post depends on what your client wants.
If he wants as much volume in the face, make a big one right below his ears. Remember to tell him that the bigger the port, the more different it sounds from what comes out of the the front and with the port right underneath his ears, the sound from the port will be very dominating. That is the kind of port that you see the most and the reason that so many dislike ports. Its also the kind of port being discussed endlessly on places like this one.

I personally prefer a smaller port, some 35mm diameter placed some 12 cm from the neck on the upper bout. This gives much more balance. You can hear the port and the front, it gives you a more "surround" effect and it doesnt dominate the overall sound.

Between these two extremes, you have all kinds of posibilities.
As with everything in instrument making there are no simple answers and therefor, the discussions we´ve had so far about ports have been on a VERY low level. Because very few have much experience and know what they are talking about.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 22 2014 7:50:14

keith

Posts: 1108
Joined: Sep. 29 2009
From: Back in Boston

RE: ports (in reply to jshelton5040)

john, are you aware of al carruth? al has done research on ports and even built a "test mule" with ports everywhere that are plugged, etc. al is very friendly and helpful and maybe an e-mail to him might be in order.

here is a link to a paper he wrote about ports--from his website

http://www.alcarruthluthier.com/Downloads/sidePorts.pdf

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 22 2014 12:06:24

jshelton5040

Posts: 1500
Joined: Jan. 17 2005

RE: ports (in reply to keith)

quote:

ORIGINAL: keith

john, are you aware of al carruth? al has done research on ports and even built a "test mule" with ports everywhere that are plugged, etc. al is very friendly and helpful and maybe an e-mail to him might be in order.

here is a link to a paper he wrote about ports--from his website

http://www.alcarruthluthier.com/Downloads/sidePorts.pdf

The customer was thinking something about the size of a dime (maybe 1/2") but that seems kind of small to me, hence my question.

I appreciate the knowledge from Anders and the link to the Carruth paper. I read this fascinating paper some time ago and have always found Al Carruth's information thought provoking. I think I'll probably go with the diameter Anders recommended.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 22 2014 14:18:03

estebanana

Posts: 9351
Joined: Oct. 16 2009

RE: ports (in reply to jshelton5040)

Make the sound hole slightly smaller. I had a correspondence some years back with a guy on the Left Brain luthery group who also happened to be an engineer. All this is still not exact science, but he recommended closing the main soundhole 1/8" for every 3/4" to 1" of sound port, given it's a circle shape. It makes sense to close the main somewhat and the idea was to close the area on the main soundhole about as much as you open the sound port.

Making the port much bigger than 7/8" and you get diminishing returns. But it depends on the guitar. The farther from the main sound hole the better it seems for clarity. The sound port and main sound hole seem to compete if they are too close together. That said I don't do them any longer unless pressed. I don't think they are that interesting after having done them for a couple years.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 22 2014 19:59:03

jshelton5040

Posts: 1500
Joined: Jan. 17 2005

RE: ports (in reply to estebanana)

quote:

ORIGINAL: estebanana

Make the sound hole slightly smaller. I had a correspondence some years back with a guy on the Left Brain luthery group who also happened to be an engineer. All this is still not exact science, but he recommended closing the main soundhole 1/8" for every 3/4" to 1" of sound port, given it's a circle shape. It makes sense to close the main somewhat and the idea was to close the area on the main soundhole about as much as you open the sound port.

Making the port much bigger than 7/8" and you get diminishing returns. But it depends on the guitar. The farther from the main sound hole the better it seems for clarity. The sound port and main sound hole seem to compete if they are to close together. That said I don't do them any longer unless pressed. I don't think they are that interesting after having done them for a couple years.

Thanks Stephen, that seems very logical. I've never put a port in a guitar so after 50 years of building I am a complete novice when it comes to ports. It's one of those innovations that I intuitively discarded but perhaps I was wrong (nothing new in that

).

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John Shelton - www.sheltonfarrettaguitars.com

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 22 2014 21:20:19

estebanana

Posts: 9351
Joined: Oct. 16 2009

RE: ports (in reply to jshelton5040)

quote:

Thanks Stephen, that seems very logical. I've never put a port in a guitar so after 50 years of building I am a complete novice when it comes to ports. It's one of those innovations that I intuitively discarded but perhaps I was wrong (nothing new in that ).

_____________________________

John,

I have thought and rethought the sound port and done it many times and I feel it is ok, but if it was really a super great thing Torres would have invented it! Guitars work just fine without them. They are simply different. Oftentimes they don't do much at all except make the guitar more nasal sounding. I have gotten to the point where I don't want to hear the overtones and inside "noise" of the guitar in my face. But as you say we change our minds intuitively and change them back as we get more information and understand our work. I may change my mind again in a few years.

You should think about putting a backing plate on the inside of the port. The other possible route is to build the guitar without the port and put a backing patch where the port is intended to be and then build without it. ( you should put a backing patch on it anyway) Later if the customer decides they want the port the area of the port is pre backed with a support. You can make the hole with a hole saw or Dremel later. But then you have the issue of refinishing the edge of the hole.

While you're at it, if you have not already read Al Carruth's thoughts on break angle at the saddle. He did some tests on that and If I remember right, he determined break angle is not as critical as some think.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 2:48:47

estebanana

Posts: 9351
Joined: Oct. 16 2009

RE: ports (in reply to jshelton5040)

quote:

The other interesting experiment that we'll be doing this season is a Paulino Bernabe inspired blanca with minimal fan bracing and a staged top. I'll post pictures of the interior at the appropriate time.

What is a staged top? I don't understand that term.

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https://www.stephenfaulkguitars.com

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 2:53:49

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: ports (in reply to jshelton5040)

This with the soundhole size...... I´m not to sure it matters. I´ve built various ported guitars with normal sized and with smaller soundholes and I dont really hear much of a difference. There are many theories out there which have not been tested very much. Because something sounds logical doesnt always mean that it will work that way. We tend to make up many things in our minds.

To me, the placing of the soundport is very important in order to not get that nasal sound. The nasal sound becomes stronger when you make the port bigger.

Its not a bad idea to make the port smaller than what I said. That was what I find to be max. Since I make inlayed soundports, its difficult to say the exact size of the "hole".

I agree with stephen that the port is not the most important part of a guitar, but I personally prefer a guitar with a port that is not to big and placed as I wrote before.

Yes, reinforcement is important. A patch on the inside of the sides is the best, but you can also simply glue 2 sticks on the sides between the front and the back, one on each side ot the port, just like it has been done for ages on the soundhole. Thats what you (should) do if you make a port on a finished guitar which has not been prepared for a port with a patch on the inside.

Images are resized automatically to a maximum width of 800px

Attachment (1)

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 7:00:39

keith

Posts: 1108
Joined: Sep. 29 2009
From: Back in Boston

RE: ports (in reply to estebanana)

estebanana--i copied and pasted this post by alan carruth from delcamp

by Alan Carruth » Sunday 31 March 2013, 00:39 am

Larry Schultz wrote:
"Having built a flamenco with an incorrect neck angle that required lowering both the bridge and saddle, and winding up with a shallow break angle, I found a significant lowering of volume. I believe a steeper angle puts more downward pressure on the saddle and results in better transfer of string energy to the top."

I have done an extensive and careful series of experiments on this. As usual, it's more complicated than you might like it to be, but the short answer is that string height off the top can have a major affect on the sound, where break angle, by itself, does not. Remember, you changed both. This was established on a guitar that was set up to allow for changing the two independently through some carefully done listening tests using 'standard' plucks recorded in a 'semi-anechoic' closet, as well as extensive analysis of the plucks themselves for level, duration, attack, and overtone content. Listeners could easily pick out a change in string height off the top, but could not hear a change in break angle, reliably. Altering the string height off the top also changed the overtone content of the sound in ways that one would expect to be audible, while altering the break angle gave no significant change in the recorded sound.

A higher break angle does increase the download on the saddle, and, more importantly in some ways, the tipping force. This does not translate into more sound being passed to the top of the guitar, though. Basically, the 'vertical' component of the transverse string motion, which is the main driver of the top, produces a known force on the bridge top that must be smaller than the downbearing force of the string on the saddle. If the downbearing is too small then the string will hop of the saddle top at some point in it's vibration cycle, and you'll know it by the buzz. So long as the break angle is sufficient to keep the string in contact at all times (and that only requires about 6 degrees of break angle) all of the string signal will be transmitted to the top.

I could go on: as I say, this gets sort of complicated when you look at all the details. The important take away is, though, that break angle is not as important as string height off the top. The devil is in the details, of course, and it's possible that the details in some particular case could cause a change in break angle for a particular guitar to have an effect on the sound by itself. I'm not saying 'never', but 'pretty darn seldom' would not be too strong if what I've seen is correct.

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 11:35:06

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: ports (in reply to jshelton5040)

Keith, interesting post,
But as long as it doesnt say anything about the stringheight used in the test or the kind of guitar being tested, I cannot use it for much.
Flamenco guitars are different from classicals and steelstrings. .
What Carruth calls the "tipping force" is actually important. We need some of it, but not to much and therefor the breakangle IS important, but the general idea that more breakangle is better I totally disagree. Enough is enough, but I count both the height needed for the strings to stay firmly on the saddle, but also enough tipping force. On the other hand, a very strong breakangle can produce to much tipping force, which puts to much tension on the soundboard.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 12:12:56

keith

Posts: 1108
Joined: Sep. 29 2009
From: Back in Boston

RE: ports (in reply to Anders Eliasson)

anders, alan has posted a plethora of information about break angle as well as a plethora of other guitar topics. as i recall his strings above the soundboard was something like 15 or 17mm--something in the stratosphere. by the way, i have said this before, i like the insert you do for your port.

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 13:38:04

Ricardo

Posts: 14806
Joined: Dec. 14 2004
From: Washington DC

RE: ports (in reply to keith)

quote:

ORIGINAL: keith

anders, alan has posted a plethora of information about break angle as well as a plethora of other guitar topics. as i recall his strings above the soundboard was something like 15 or 17mm--something in the stratosphere. by the way, i have said this before, i like the insert you do for your port.

http://youtu.be/tyBUMntP6DI

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 13:58:23

jshelton5040

Posts: 1500
Joined: Jan. 17 2005

RE: ports (in reply to estebanana)

quote:

ORIGINAL: estebanana

What is a staged top? I don't understand that term.

It's an entirely inappropriate antiquated term for tops whose thickness is varied rather than uniform or simply tapered at the edges. It's normally used with minimal bracing. We experimented with it off and on for several years with fascinating although somewhat mixed results. Back in the 80's we built quite a few double bodies with tops that were over 1/4" thick in some spots. It worked well with flat tops but I haven't tried it with our current top shape which is parabolic from end block to 12th fret.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 15:12:13

estebanana

Posts: 9351
Joined: Oct. 16 2009

RE: ports (in reply to Anders Eliasson)

quote:

Keith, interesting post,
But as long as it doesnt say anything about the stringheight used in the test or the kind of guitar being tested, I cannot use it for much.
Flamenco guitars are different from classicals and steelstrings. .
What Carruth calls the "tipping force" is actually important. We need some of it, but not to much and therefor the breakangle IS important, but the general idea that more breakangle is better I totally disagree. Enough is enough, but I count both the height needed for the strings to stay firmly on the saddle, but also enough tipping force. On the other hand, a very strong breakangle can produce to much tipping force, which puts to much tension on the soundboard.

_________________________

Go to Al's website and read about his tests on guitar mechanics. He goes into great detail about the experiments and how he does them. His analysis of string mechanics is a major work.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 15:13:44

estebanana

Posts: 9351
Joined: Oct. 16 2009

RE: ports (in reply to jshelton5040)

quote:

It's an entirely inappropriate antiquated term for tops whose thickness is varied rather than uniform or simply tapered at the edges. It's normally used with minimal bracing. We experimented with it off and on for several years with fascinating although somewhat mixed results. Back in the 80's we built quite a few double bodies with tops that were over 1/4" thick in some spots. It worked well with flat tops but I haven't tried it with our current top shape which is parabolic from end block to 12th fret.

Sounds fun. Like one of those top bracing things I lay awake at night thinking about.

So the Bernabe plan is the one with three braces and then some strategically thicker areas? I want to see how that turns out.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 15:17:23

jshelton5040

Posts: 1500
Joined: Jan. 17 2005

RE: ports (in reply to estebanana)

quote:

ORIGINAL: estebanana

You should think about putting a backing plate on the inside of the port.

I plan to use Alaska Yellow cedar as a backing plate since it bends so nicely across grain. I have a couple of billets of it that I consider pretty much worthless except for that quality.

quote:

While you're at it, if you have not already read Al Carruth's thoughts on break angle at the saddle. He did some tests on that and If I remember right, he determined break angle is not as critical as some think.

Read it sometime ago. I've tried to follow his writing since he's always struck me as someone with a remarkably logical approach to building. I wish I could be more like him.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 15:19:04

Tom Blackshear

Posts: 2304
Joined: Apr. 15 2008

RE: ports (in reply to Anders Eliasson)

I'll hand it to you Anders, your sound ports are artistically done and there is a justified and reasonable necessity for those players who feel their need for one.

I remember when I was a player and used to rest my head on the side of the upper bout to gain a different perspective of the sound being produced.

Essentially, anything can go for artistic work, as this is an ever-changing world we live in. So, I salute you in anything that you are creatively inspired to build in a guitar, especially this beautiful sound port design that any artist should respect.

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Tom Blackshear Guitar maker

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 15:49:39

britguy

Posts: 712
Joined: Dec. 26 2010
From: Ontario, Canada

RE: ports (in reply to Tom Blackshear)

quote:

I'll hand it to you Anders, your sound ports are artistically done

Yes! I thought so too. Very tasteful design. Nicely done. . .

But - maybe I'm old-fashioned - I would never want one on any of my guitars. . .

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Fruit farmer, Ontario, Canada

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 19:25:48

Tom Blackshear

Posts: 2304
Joined: Apr. 15 2008

RE: ports (in reply to britguy)

quote:

ORIGINAL: britguy

quote:

I'll hand it to you Anders, your sound ports are artistically done

Yes! I thought so too. Very tasteful design. Nicely done. . .

But - maybe I'm old-fashioned - I would never want one on any of my guitars. . .

That's the beauty of this art, just look at all the different works that come out of guitar shops these days. It wouldn't surprise me if something new in another avenue of design won't make its way into the market before too long.

There are people who will buy the newest innovations and designs, just to have one. This is what keeps us in business. But as for me, I'm a strict traditionalist due to the fact that I'm a copiest of traditional styles.

This is a money making hobby for me to spend on my wife and family.

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Tom Blackshear Guitar maker

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 23 2014 20:24:26

keith

Posts: 1108
Joined: Sep. 29 2009
From: Back in Boston

RE: ports (in reply to Ricardo)

ricardo, the three amigos, one of my favorite brainless movies.

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 24 2014 12:14:48

estebanana

Posts: 9351
Joined: Oct. 16 2009

RE: ports (in reply to jshelton5040)

There there is this model:

(notice it's been cleverly recompensated )

Images are resized automatically to a maximum width of 800px

Attachment (1)

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 24 2014 14:34:41

Ruphus

Posts: 3782
Joined: Nov. 18 2010

RE: ports (in reply to jshelton5040)

Holy sh!t! That´s what I would call a port. One for hiding stickies to the gig.

How on earth can a top have taken abuse like that while the fretboard is looking near mint in the same time.
... Think I got it; the f-board might have been renewed.
Either that or the soundboard was beaten up intentionally.

Ruphus

PS:

Think I´ll store that pic for future use.

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 24 2014 17:45:34

tri7/5

Posts: 570
Joined: May 5 2012

RE: ports (in reply to Ruphus)

That's Willie Nelson's guitar. It's had some 50+ years of constant play that's why the top is worn through.

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 24 2014 19:24:46

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: ports (in reply to jshelton5040)

And Willie dont think its necessary to fix anything. He likes it an believe it will outlive himself.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 25 2014 6:50:34

Ruphus

Posts: 3782
Joined: Nov. 18 2010

RE: ports (in reply to jshelton5040)

I see. Thanks for the hint.

Last time I saw it, it had no second hole.
Guess that must have been some time ago, when yours truely was having less dents on the top as well.
Time passes.

Ruphus

REPORT THIS POST AS INAPPROPRIATE | Date Sep. 25 2014 8:57:58

Ricardo

Posts: 14806
Joined: Dec. 14 2004
From: Washington DC

RE: ports (in reply to estebanana)

quote:

ORIGINAL: estebanana

There there is this model:

(notice it's been cleverly recompensated )

damn, willy got some mean golpe and rasgueado technique.

Images are resized automatically to a maximum width of 800px

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 25 2014 16:22:52

estebanana

Posts: 9351
Joined: Oct. 16 2009

RE: ports (in reply to jshelton5040)

Do you know what brand it is? I'll tell you, it's a Martin nylon string model.

One of these: http://www.guitar-museum.com/guitar-41101-Martin-N-20-classical-nylon-string-guitar

If ya'll was wonderin.

Willie Nelson has someone on his staff hand carry that guitar at all times and guard it everywhere they go on tour because it is so valuable as his symbol. If something happened to that guitar he would lose much stage presence, his audiences expect that guitar

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

I suppose we should develop a meme out of this picture to give to unsuspecting guys who log in and want to cry about a mirco scratch in their new flamenco.

I know just the Foro member for this job.

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REPORT THIS POST AS INAPPROPRIATE | Date Sep. 25 2014 19:56:10