top tuning.. how to?

Construction and repair of Classical Guitar and related instruments
Jose Marques
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top tuning.. how to?

Post by Jose Marques » Tue May 16, 2017 2:22 pm

Hello

I didn´t found some topic with the answers of my questions then i will leave here, if there are i just didn't saw where sorry.

Well, i never tune my tops, i do like the masters that i have learned like Romanillos for example, i believe i dont need to explain you all have knoladge about that process.

Like i'm always looking for more info in every aspect of guitar making i was looking for videos of some luthiers that tune the top...

I have some questions, is F# the best tune? i saw people that says that G is the best... well maybe this will be like everithing else, is a matter of taste .

Theres other thing that makes me bristle, i saw some guys that use , for example one guitar or a tone producer and than tap the top to achieve that note... i believe that is a ok process but i saw some luthiers that after have done that they say "yes that's the note" but my ear says, no no no is not ... well maybe i'm wrong... or not

There exists other precise way? i have used my smalls tuners and doesn't work...

what do you use ?
I'm a Luthier living in Bury st Edmunds UK

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georgemarousi
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Re: top tuning.. how to?

Post by georgemarousi » Wed May 17, 2017 9:43 am

Hi Jose,

though I'm not a luthier, my input might be helpful:

My Bernabe Especial top, which is a very good guitar, is tuned in F#. A local luthier that set it up has mentioned / shown this to me - but to be honest I have not realized it up to then.

My Alhambra Luther India is tuned in G. It is obvious as it has a very strong G.

The conclusion I have to state is that I personally prefer the F#, as the G is many times there ( cause of the open G string ), and I believe it's better to avoid that coordination phenomenon if possible. :)
--Classicals--
Paulino Bernabe Especial 2009
Ramirez 1A 1980
Alhambra Luthier india 2012
Juan Martinez nr 55 (the return @2014)
Yamaha cg 110 (as a kid @88)
--
student again since 2015, to my degree @..? - God bless!

Jose Marques
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Re: top tuning.. how to?

Post by Jose Marques » Wed May 17, 2017 2:25 pm

georgemarousi wrote:
Wed May 17, 2017 9:43 am
Hi Jose,

though I'm not a luthier, my input might be helpful:

My Bernabe Especial top, which is a very good guitar, is tuned in F#. A local luthier that set it up has mentioned / shown this to me - but to be honest I have not realized it up to then.

My Alhambra Luther India is tuned in G. It is obvious as it has a very strong G.

The conclusion I have to state is that I personally prefer the F#, as the G is many times there ( cause of the open G string ), and I believe it's better to avoid that coordination phenomenon if possible. :)

Thank you for your post George .

Yes i saw that the luthiers that use to tune the tops they prefer the F# ...
i never had done that but i will soon

now i just need to find out the best method, with ear is of but i need something more precise i believe...
I'm a Luthier living in Bury st Edmunds UK

Alan Carruth
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Re: top tuning.. how to?

Post by Alan Carruth » Wed May 17, 2017 4:54 pm

Generally the pitch you hear when you tap on the top is actually the 'main air' resonance. This is often about an octave below the actual 'top' resonant pitch, and masks the sound of the top. When people talk about 'the pitch of the guitar' this is what they usually mean.

In order to hear the actual top resonance (more or less) you need to block off the sound hole. The easiest way to do this for this purpose is the reach in between the strings with your fingers and use them and your thumb to pinch the upper top brace and fingerboard to hold the guitar up. Try to cover as much of the hole as you can without actually touching the edge of the hole. This blocks off most of the air flow through the hole but doesn't impede motion of the top. Then you can tap in the middle of the bridge to drive the 'main top' resonant mode. It is often clear enough that you can get a decent idea of the pitch, but usually too brief in duration for a tuner to pick up.

Sometimes you can also hear a couple of other top resonances that that can also color the sound. Try tapping on the bridge wing while just touching the bridge in the center, so that the bridge can rock freely from side to side without necessarily moving in and out much. This is sometimes called the 'cross diole' mode. It could be somewhere around the open B string pitch, although it can vary a lot. Again, touching the center of the bridge you might also try taping in the lower bout, between the back of the bridge and the tail. This 'long dipole' resonance is usually somewhere near F on the high E string, although, again, it can vary.

Jose Marques
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Re: top tuning.. how to?

Post by Jose Marques » Thu May 18, 2017 11:56 am

Thank you Alan

I believe that you are talking about tuning after the bridge and strings are on, my question is before, wen you are shaping the fans, as i saw some luthiers do.

Yes i believe that none tuner can "listen" the notes for us to tune, it must be only by ear.

Thank you
I'm a Luthier living in Bury st Edmunds UK

Jose Marques
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Re: top tuning.. how to?

Post by Jose Marques » Tue Jun 06, 2017 3:30 pm

i'm talking about what you see un video bellow, this luthier tunes with other guitar and by ear but i look for some idea to tu using a tuner or something similar, but be accurate

https://www.youtube.com/watch?v=Mwi-j2ToB3o
I'm a Luthier living in Bury st Edmunds UK

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Trevor Gore
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Re: top tuning.. how to?

Post by Trevor Gore » Wed Jun 07, 2017 12:43 am

Factory-made guitars aren't "tuned". They exit the manufacturing process and they are what they are. As these guitars are not particularly responsive, it doesn't matter too much. However, the more responsive you make a guitar, the more important it is to have it "tuned" properly, because wolf notes and out-of-tuneness (note frequency shifts) become a lot more apparent the more responsive a guitar is. What you hear, though, when playing, is the tuning of the finished instrument, complete with its bridge, saddle, strings, finish and with the top attached to the rest of the box. All the aforementioned alter the tuning of the box in particular ways and whilst in theory there should be a correlation between the free plate tuning and the finished instrument tuning, in practice there isn't, because it is impossible to predict to a sufficient extent the affect of all the other variables that alter the tuning between that of the braced plate and that of the finished instrument. So what is required is an understanding of how each and every one of the constructional processes is going to alter the tuning of the guitar (and hence change its sound) and manage these all the way through the building process so that you end up where you want to be. That starts with measuring the wood properties so you can calculate how thick to leave a top (and back) so that they will vibrate in a particular way, through to selecting the bridge and saddle mass and stiffness so that the instrument's resonant frequencies are pitched in the right zone. The final step is using a selection of techniques to adjust the resonances of the finished instrument to your requirements. So anyone telling you that tuning a free top to a specific note is "the secret" is missing most of the story.

Ryeman
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Re: top tuning.. how to?

Post by Ryeman » Wed Jun 07, 2017 1:03 pm

I have watched the video twice and am not sure what to make of it. To be honest I couldn't hear a lot of difference in pitch or sound duration from when he tapped the front at the beginning of the video to when he tapped it at the end after making all the "improvements". (And it is easy to compare at the end by going straight back to the start) It was difficult to compare its pitch to the note on the guitar, because he only played the guitar note once, very quickly, and in a perfunctory manner. It would have been better if someone else had played the guitar, in synch with him tapping the unfinished top.
In short, to much smoke and mirrors....

Alan

Jose Marques
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Re: top tuning.. how to?

Post by Jose Marques » Wed Jun 07, 2017 2:25 pm

thank you for your answers :)
yes i had made this questions because i have heard a lot about tune the top, not all guitar, and i just try to understand this, as a builder i'm always try to know diferent aprouches and tecnics and this one i really dont see how can do a good top... well, in fact if you do all tops with one note , for example F, you will have all your guitars very near sounding of one of each other, even if everithing else will change and of course will change, it will be dificult you put always a bridge with the same pich for example.
Ryeman i thougth the same i din't saw diferences as well, that is the reason that i wish to have something more precise... not only the ear..
and to "tune" the top if you start with a top with G and wishes to hava one F i believe that you must take i+one big amount of wood to down one tone.. or not?
is something that i'm not see here????

I never had done this process, i just do like Romanillos teaches in hes book and works fine... but i never stop triyng to know other methods
I'm a Luthier living in Bury st Edmunds UK

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Jonathan Lamb
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Re: top tuning.. how to?

Post by Jonathan Lamb » Wed Jun 07, 2017 2:35 pm

It's a facinating aspect of the lutier doing best work. I am interested that you tune the TOP like the video, and also the box itself... and so manipulate the harmonic response of the finished instrument. Thank you so very much.

Ryeman
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Re: top tuning.. how to?

Post by Ryeman » Wed Jun 07, 2017 3:49 pm

Hello Jose,
I am pleased someone else found it hard to hear the difference!

Alan

Alan Carruth
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Re: top tuning.. how to?

Post by Alan Carruth » Wed Jun 07, 2017 6:11 pm

Trevor is correct in pointing out that tuning a 'free' (not glued to the box) top to some specific pitch won't necessarily get you where you want to go. There is no simple general relationship between the pitch of that 'free' top and the pitches of the resonances of the assembled instrument that actually shape it's sound. It's all quite context specific. That doesn't mean that tuning the top is useless, it just means that you have to look at it in the right way.

A hundred years ago the model T Ford was the state of the art in affordable autos. It used a different ignition system than the one that became common later, or that we're used to now: it was based on magnetos. Each cylinder had it's own magneto, which worked like a buzzer to produce an alternating current from the car's battery, which could be stepped up to make the spark in the plug. The device worked best at a certain spark gap, which corresponded with a particular frequency; about C~262 Hz. Rather than use a feeler gauge to measure the gap directly you would adjust it using a C tuning fork; when the buzz matched the tuning fork you had the right gap. This seems to be why we refer to 'tuning up' an engine. Getting it to work right is only peripherally related to the pitch of the buzz, which is just a sign that the gap is correct. On modern engines the whole process is moot anyway, but we still use the century-old term.

The pitches of the 'free' plate modes are rough indicators of the overall relationship of stiffness to mass of the top, but that's about it. The 'correct' frequencies vary widely depending on what sort of guitar you're making. Things like adjusting them to be at harmonic ratios or whatever don't matter. What does seem to matter is the shapes of those modes, and how well defined that are in pitch. Well defined modes have lower losses than ones that are not as clear, which seems to be an indicator of things like stiff or loose spots. This is coupled pretty reliably with mode shapes that are well defined and smoothly delineated. My experience suggests that tops with more and better defined modes tend to produce better guitars.

It is also entirely possible that I've been fooling myself. ;)

printer2
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Re: top tuning.. how to?

Post by printer2 » Wed Jun 07, 2017 9:55 pm

Alan Carruth wrote:
Wed Jun 07, 2017 6:11 pm
It is also entirely possible that I've been fooling myself. ;)
And even if you fool yourself, as long as the outcome is good guitars any method is valid.
Fred

Alan Carruth
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Re: top tuning.. how to?

Post by Alan Carruth » Thu Jun 08, 2017 4:44 pm

printer2 wrote:
"And even if you fool yourself, as long as the outcome is good guitars any method is valid."

...up to a point. The problem with doing the right things for the wrong reasons is that they're still the wrong reasons. As long as they work you're OK, but when they stop working, as they certainly will, you end up doing the wrong things and go from bad to worse.

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Section_10
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Re: top tuning.. how to?

Post by Section_10 » Sat Jun 10, 2017 12:21 am

It makes perfect sense to use this method or at least be mindful of tapping tones of different plates while building. Then again, the mystery of what makes a great guitar still exists, some makers don't do any tapping or trying to achieve certain notes and their guitars turn out great. Now if we measure those guitars, they may fall in line with works great. But the overall outlook isn't so much any particular tone in mind, but a system you're building. The bridge has a weight and tap tone, gets glued to the soundboard which has a tone, but then it gets braced which alters tone quite a bit. Once fully built the soundboard is actually a flexing piece of a soundwave board that interacts with the sides and back...So many resonances to talk about. Then again, i've had guitars Aussie style with thick non-braced backs that gives the guitar a more focused sound, but of course since you've just cut out a lot of resonances that interact with the soundboard. Overall, you're not building one resonance, you're building an interacting system. The built soundboard has many supporting resonances even though it taps at a certain tone, my guitars range from 157hz, very low, 225hz, to 259hz. Two of them having a main body air resonance of around F# or G, but the lower one at a very low E. As for main air resonance, yes I would, in my opinion, go for an F# goal. I think it works best for many reasons, a good compromise.

EDIT: important note, I don't build guitars, just a passion to understand them as well as play them. "my guitars" means what I play/own/looking at. I go through a lot.

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