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Robin's build #004

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Peter C-F
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Question.  Do you tune the braces when carving, or are you focussing more on dimensions?


   
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Robin
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@peter-c-f 

Question.  Do you tune the braces when carving, or are you focussing more on dimensions

This is my first acoustic build, I wouldn't have a clue how to tune a brace. I'm following the directions in Mark's course as close as I can that give dimensions for the braces, but the carving is freehand, so I'll know if I've got it right if I ever get strings on it.


   
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Peter C-F
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Thanks for the answer.


   
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Rocknroller912
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@peter-c-f 

Braces are usually tuned by holding the plate very lightly till it rings. Some people can tell the pitch by ear but normal humans use a guitar tuner with a built in microphone

Removing wood will raise the pitch I think. Can’t remember what the note should be but if you google it should be available somewhere. Back and front are tuned an interval apart, say a fourth or fifth.

Some people call me a tool, others are less complimentary. Tools being useful things.


   
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Robin
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@rocknroller912 @peter-c-f

I've just watched Mark's "Black Art" video of the acoustic course where he talks about tap testing. He also goes on to say that making and carving the braces to the dimensions given, which have been arrived at by minds greater than ours, should result in a good sounding guitar. So thats what I plan to do, I will tap test it as well,  to hopefully hear it ring rather than a dull thud. I'll report back when I get to that stage.


   
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Rocknroller912
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@robin 

Tap tuning takes a lot of experience. Some makers even tune after the body is closed by scraping the outside of the soundboard and tapping to get a ring.

Some people call me a tool, others are less complimentary. Tools being useful things.


   
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Robin
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@rocknroller912 

I've just tried a tap test on the back, it surprised me by registering on my tuner. It didn't show on the tuner with every tap, but when it did register, tapping in various spots, it showed a fairly consistent A# ish. I'm thinking that once its glued to the sides, surely that's going to change. I think I'm quite happy that it makes a sound at all.


   
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Rocknroller912
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@robin 

A# sounds a bit off. I watched a video on classical building where the top was an F and I think steel string is lower. Shaving a bit off to produce a G might make a better sound.

 

This post was modified 6 months ago by Rocknroller912

Some people call me a tool, others are less complimentary. Tools being useful things.


   
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Peter C-F
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I did some research on tap tuning once I became aware of it.

The main thing I took away is how the vibrations of the string are sent to the body via different mechanisms that are specific for each type of instrument.

For instance, a guitar can sustain a sound because the vibration of the strings is transferred through the bridge to the soundboard - this then becomes the source of compression and rarefaction of the air inside the guitar body for some time, until the vibrations become so small that it no longer registers.

With violin the vibration is transferred to the body in a similar manner, with one difference: there is a soundpost fitted between soundboard and backboard.  This soundpost leads to a loss of sustain capability - which is why a violin gives a sort of dud sound when struck.  The sound actually comes from constant vibration of the string brought about by the bow.

 

Since the board is at this moment not connected to the body, there is no possibility of  getting a sustain - that is the reason why your tuner cannot pick it up every tap.  It would help if you can somhow get an electrical sustain pedal between the tuner and the microphone.  I recently bought a downloadable tuner with tap-tuning capacity (peterson tuners) and cannot get it to work without putting a sustain between microphone and computer.

 

If you are interested, I found 'The Art of Tap Tuning' by Roger H. Siminoff a great source of information - not just theoretical, but more importantly practical tips.

The most practical one being when you remove wood you lower the pitch.


   
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Robin
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@peter-c-f 

If you are interested, I found 'The Art of Tap Tuning' by Roger H. Siminoff a great source of information - not just theoretical, but more importantly practical tips.

Thanks for the book recommendation, I've managed to borrow from an online library, I can take it out for an hour at a time. Ive read the first chapter, very interesting reading.

@rocknroller912

A# sounds a bit off. I watched a video on classical building where the top was an F and I think steel string is lower. Shaving a bit off to produce a G might make a better sound.

Once I've read this book, maybe I'll have some clue as to where to shave wood from. The important bit I've got from the book so far is not to have the component parts of the guitar tuned to the same note.


   
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Peter C-F
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Posted by: @robin

hanks for the book recommendation, I've managed to borrow from an online library, I can take it out for an hour at a time. Ive read the first chapter, very interesting reading

glad to have been of some help


   
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Rocknroller912
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@robin 

violins are tuned F front and F# back

Some people call me a tool, others are less complimentary. Tools being useful things.


   
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@peter-c-f 

The sound waves on bowed and plucked instruments are different. I watched a science demo when I attended classes at violin school using transducer pick ups and an oscilloscope. 
For bowed it’s a sharp sustained attack, followed by a rapid fall away. For plucked it’s a shorter attack, followed by a longer slower sustain. By placing small amounts of blue tack on either the violin tailpiece or guitar soundboard it was possible to alter the sound wave. 

Some people call me a tool, others are less complimentary. Tools being useful things.


   
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Peter C-F
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@Rocknroller912

 

Thanks for your 3explanation.  You describe what happens, I was attempting to describe why - so I gues we complemented each other in thid conversation 😀


   
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Robin
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@rocknroller912  @peter-c @markbailey

  1. This is an extract from the book ( 'The Art of Tap Tuning' by Roger H. Siminoff ) these are suggested target notes (not definitive) for the braces with the soundboard/backboard edge secured in a frame.  The backboard centre brace 'D' has been pencilled in as 'A' when tap tested held free. I'm in danger of dissappearing down a rabbit hole here, maybe I should just follow Mark's course and finish it, but I haven’t copied Mark's body size, am I just overthinking this.
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Peter C-F
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It certainly was not my intention to send you 'doon a wabbit 'ole'.

I am sure that you will make a good sounding guitar whatever route you choose. After all, best results are based on guidance as well as experience.  And you cannot get one without the other (or something such whatever)


   
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Rocknroller912
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@robin 

Thanks I haven’t seen this before and only have his mandolin book. For a first build I would stick with Marks course and it will be a good guitar. Tap tuning is fairly advanced.

Some people call me a tool, others are less complimentary. Tools being useful things.


   
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mark bailey
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If you are going to 'tune' any of the braces, plates, chambers make sure to offset your tuner by 1/4 note (A=431)

The last thing you want is parts tuned to concert pitch.

Until you have a few builds under your belt I would stick with standard dimension from an existing plan.

If you want more info  'The Art of Tap Tuning' by Roger H. Siminoff is the book to read as suggested by @peter-c-f and @Robin

This post was modified 6 months ago by mark bailey

Measure twice, cut once...


   
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Robin
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@markbailey 

Thanks for your input Mark, I've read the book and I think, with me being an engineer, I got caught up in theory and numbers. I'll stick with your brace carving directions, I've also decided to use a pre slotted fretboard again, so I'll be ordering one from you soon, I'll wait till the xmas postage rush is over.


   
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Robin
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Made my kerf linings now, I think the the flat sawn strips are more flexible than the quarter sawn I used when making my jig. Dry clamped the trickier side of the front, looking okay.

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