Great sounding "Taps"?

[Steve Sorensen]

I'm still waffling on the idea of jumping into the whole stroboscope tap tuning arena. For my first tops, I used a bright light from behind to get what looked like an even "Halo" in the recurve and stopped at just a tad thinner than the Simonoff graduations.

A red cedar top I carved has a bright "Ping" with no tone bars, while my first spruce top just sounded like a thin board until I added tone bars.

Still, I have no idea with sound I should hear when I tap a top or assembled body.

I'm wondering if any experienced builders have posted recordings of the tap sounds they consider "optimal".

Little by little I am gathering a catalog of mandolin recordings where the instruments grab my ear and sound like what I hope to someday attain in my builds. (Sim Daley is the current ear-grabber)

It would be great to get some sound recording references of what the body components tap out for typical F5 builds.

Anybody have top tapping recordings to post?

[peter.coombe]

Personally I think it is a waste of time trying to tune a top to particular frequencies. It is far more important to note the relative tuning of the top and back. This sort of stuff will come with experience. I have published a whole bunch of top and back tunings, but they are for oval hole A mandolins, so not of much use for an F5. Oval hole tunings don't work for F soundhole mandolins. Anyway, you might like to read the paper any way.

http://www.petercoombe.com/jaamim8.html

[Steve Sorensen]

Peter,

Thank you for responding. I have poured over your papers. Excellent work that helped me appreciate the depth of science on the subject.

I used to be in the wine industry. Reminds me of the infinite combinations of science, artistry, voodoo, technology and luck that made each wine from each vintage so different.

Still would love to hear recordings of carved tops (before and after adding tone bars) to help create an aural reference. I know expertise grows with experience . . . and there is a wealth of experience in the Cafe!

Steve

[Lefty Luthier]

A simple method to test the veracity of tap tuning is to use an audio generator, (downloadable on line) hooked to your lap top computer speaker to run a frequency sweep and either record or just listen to the change of amplitude as the various resonances are passed. In my experience, not only is individual component tuning possible, it is the only way to really control the acoustic signature of an instrument. There is no doubt that all components must be tuned in a complimentary fashion and final "voicing" is the ultimate objective but unless you start off controlling top, tone bars and back resonances, you will never have actual control of the final result.

[sunburst]

Like Peter, I abandoned any attempts to "tune" parts to specific notes very early in my building journey. I still tap and listen, but I don't record anthing, and I don't know how to say what it is I'm listening for... perhaps I don't even know what I'm listening for. Those sounds are only a small part of it for me; stiffness, feel, mas, thickness and arch shape get more attention than tapping and listening. As is often the case, I have two mandolins in process right now that I've built together thus far, mostly concentrating on the stiffness, feel, mas, arching and thickness of the plates. If I tap the tone bars, the "notes" that come from each top are almost identical to one another. That usually happens, and I suppose that indicates that what I'm doing is pretty consistent, and I suppose I could work toward tuning them to consistent notes, but to me that seems backwards.

[barry k]

....and once again I agree with John. Strobe tap away if you want to, but experience will provide the results that you want. If it does not sound good when your finished, just stand it in front of some speakers or de-bunk it ( just kidding)

[Skip Kelley]

Thanks guys for the replies! It lets me know I am in good company. I strive to arrive at a relative tuning of the top and back like Peter does. John, I am like you in that my tone bars when tapped are very close to each other. I know I am getting more consistant as well.

[Steve Sorensen]

All,
If you have tops or bodies and get bored . . . I would love to hear MP3s of how they tap at their current stage.

I'm banging on the tops I've carved, the current body I'm binding and my Loar trying to get some perspective.

Thanks,
Steve

[Rob Grant]

FWIW: Basically I want a nice, crisp response when I tap the tops with my old felt covered ex-piano hammer. Like the difference between a fresh piece of celery and a soft carrot.<g> Well, how about a timber marimba key and a lead sash weight?<G>

If I was concerned about a stroboscope, and a precise note, I'd of given up on this game years ago. My aim is to make 'em as light and responsive as I can without sacrificing strength. I still struggle with the weight issue, but I don't think I've produced a "dud" yet.

[peter.coombe]

I was thinking about this stuff last night and decided a brief explanation of my latest paper was in order, so here goes.

The most important part of the paper are the graphs. What I have presented there is free plate tuning data from 25 oval hole mandolins. I have divided these instruments into 2 groups, one group are the good sounding mandolins, the other group are relatively poor sounding instruments, and there are 4 of those. I usually commented that they were disappointing, or not up to my usual standard in my order book. If you take a "poor" sounding mandolin on it's own you will probably think it sounds great (some people have), but if you compare it with a reference "good" mandolin then there is an obvious difference in the sound. This is very difficult to put into words, but most of these "poor" sounding mandolins were unbalanced, with a boomy G string and a tone that I thought was pretty ordinary when compared to the reference. These mandolins are marked with a "*" in the graphs. Now if you look at the absolute tuning frequencies they are all over the place. There is no pattern that correlates to the different groups. However, if you look at the difference in frequencies of mode 4 between the top and back, then there is a 100% correlation. The "poor" sounding group has a relatively large difference in the tuning of mode 4 between the top and the back. Referring to the tables, it appears that the difference needs to be greater than 5% to tip the mandolin into the "poor" group. Statistically, the probababilty of this occuring purely by chance is less than 1%. In scientific terms a probably of less than 1% can be taken as proof that the correlation is real and is not a fluke.

So, the conclusions are
(1) The relative tuning of mode 4 of the top and back is correlated to the sound of the completed mandolin. This is a statistically significant correlation. In my oval hole mandolins, if I tune mode 4 of the back to within 5% of the top, then I will be satisfied with the sound of the completed instrument. If the tuning is for example 10% different, then I (and others) will not like the sound when compared to a mandolin that is tuned to within that 5%.
(2) The absolute tuning frequencies are not correlated with the sound of the completed mandolin. So, if you are tuning your free plates to absolute frequencies you are wasting your time. The proof is now there for all to see. This is no longer just my and other's opinions.

I believe this is an important result. Time no doubt will tell whether it is or not.

Hope that makes sense.

[fishtownmike]

I like to tune my tap tune my tops to an G# Augmented Dominant 7th. :grin:

[peter.coombe]

:)) :))

Sorry to put a dampner on your careful and very precise efforts.

[Gail Hester]

There are essentially two types of people in the world...those who don’t believe in tap tuning, and those who do.:))

[Dale Ludewig]

Or as a friend said yesterday and I'm sure he heard it somewhere else- there are three types of people in the world: those that understand binary code and those that don't.

[Phil Goodson]

I thought the quote was "there are 10 kinds of people in the world, those who understand binary code and those who don't." :))
:grin:


Or .... "there are 2 types of people: those who divide everything into 2 groups and those who don't.":crying:

[Steve Sorensen]

I'm glad we haven't played "Taps" to this chat string!

Soooo . . .

I got the Siminoff Book/DVD on tap tuning where he explains his approach to tap tuning. Makes sense to me -- particularly the idea that the complete body of an instrument will have a tone that it responds to (or generates when tapped). That tone is relevant for the way the instrument will respond when played.

In a "Wow, that's simple" twist, my daughter's KORG tuner is fast enough to catch the note of a tapped piece of wood. (PS - this is an ad for KORG tuners . . . the best in our house!) :whistling:

Right now, the F-style body I am binding taps to a crisp C#. We'll see how that plays out.

Steve