Soundboard tuning and tone bars/bracing

[peter.coombe]

Tuning the air chamber by changing the area of the sound hole(s) is pretty basic stuff. I did that 20 years ago and the results were interesting and told me my sound holes were too big on my F sound hole mandolins so I reduced them. On Gibson type oval hole mandolins it certainly is advisable to get the main air mode in between notes, otherwise if it is tuned to G or G#, you can get a big boomy note on the G or the G# on the G strings. I have also used a fingerboard overhang to lower the air mode tuning so it sits in between notes on my Custom model mandolin which has a smaller body so the air mode is a bit higher. Some mandolins will have an air mode that is tuned below the low G strings (e.g. Lyon and Healy, most flattops) so it doesn't really matter what the frequency is. The Lyon and Healy's are lower because of the big fingerboard overhang which reduces the effective area of the sound hole. My A5 mandolin fairly consistently tunes D# nowadays so I don't worry about it and usually don't bother to measure it. However, note that most of the sound comes from the main top mode, not the air mode, so stressing out about the main air mode may be a waste of time. All this stuff is very well covered in the first Gore Gilet book, although you might need to bone up on your maths chops to fully understand it all. They talk about how the frequencies of vibration can affect tone and intonation, and how to adjust the frequencies in an assembled guitar. It is a lot more difficult in a mandolin because there is no easy access to the interior of a mandolin, so you are mostly stuck with what you have got once it is assembled.

I came to the conclusion that the only thing I could consistently observe from my database of measurements was the relationship of the modal frequencies of the top and back plates did affect the sound I was getting in my mandolins. Years later and lots more measurements, which recently have included modes of vibration of assembled instruments, I am beginning to understand why. Basically, just about everything affects the frequencies of the modes of vibration of an assembled mandolin (even the tailpiece and tuners), so there is a lot of noise from instrument to instrument because wood is so inconsistent. So any correlation between the frequencies of the modes of vibration and free plates gets lost in the noise. However, the relationship between the top and back will always remain the same. The noise is what makes music instruments so difficult to work out what makes them tick. The relationships are so numerous that no existing supercomputer can model them effectively - i.e. the degrees of freedom in the model gets too big for current technology (this is also covered in the Gore Gilet books).

[fscotte]

Once you've created the shape of the arch, it's game over.

After the arch is shaped, your goal is to reduce mass while keeping it structurally sound.

You reduce the weight by scraping away wood to its final thickness, and then replace that lost strength from scraping by using braces.

I believe any tone shaping is pointless once the arch is finalized.

IMHO of course.

[LuthieroftheDesertLoon]

Watch video link posted earlier

[peter.coombe]

I have already watched it. If you start with sound holes too small then enlarging them will give an improvement. No surprise, nothing new, no big deal. If you have already worked out what size is needed and you are reasonably consistent in your building, then all that sound hole tuning stuff becomes an unnecessary waste of time. That is why most of us don't bother.

[Graham McDonald]

Just watched Hovington's mandola tuning video. Apart from getting several bits of history quite wrong, he seems to have an incomplete understanding of stringed instrument physics and acoustics.

Cheers

[CarlM]

but again I'll say you have to cross the Mississippi to get to Montana.

Oh and by the way if I cross the Mississippi that would take me about 20,000 miles out of the way to get to Montana. So much for that little bit of "wisdom". I am not sure about Graham and Peter but I believe that would be a bit further for them to go that direction though not nearly so much

[j. condino]

Rough crowd out there in mando nerd world today....

Here lies all the answers to your questions:

https://www.mandolincafe.com/forum/t...t=condino+test

Six mandolins in two days, total effort under 15 hours. Build one, tryout your ideas on my test rig, and answer all of your own questions in less time than you guys will spend ####### on your keyboards and arguing with each other. Build it, string it up and play it as a live mandolin playing your favorite songs. Problem solved, questions answered.

As an early press release, in addition to a lot of other mandolin nerdiness, I'll be doing a live demonstration of this at the upcoming Association of String Instrument Artisans 2019 summer Symposium this June at East Stroudsburg State University.

I'll also be giving another smaller workshop and demonstration at my studio the second week of January here in Asheville if anyone is interested.

[j. condino]

In case you are curious, I just got censored for a harmless word that I've never seen blocked out; 'should have used the full strength non-harmless version...!!!

[LuthieroftheDesertLoon]

Oh and by the way if I cross the Mississippi that would take me about 20,000 miles out of the way to get to Montana. So much for that little bit of "wisdom". I am not sure about Graham and Peter but I believe that would be a bit further for them to go that direction though not nearly so much

Well CarlM, here's your geography lesson:
Its source is Lake Itasca in northern Minnesota and it flows generally south for 2,320 miles (3,730 km)[15] to the Mississippi River Delta in the Gulf of Mexico

Stated that you could not get to Montana without crossing the mighty Miss, pertains to english settlers never would have discovered Montana had they not crossed the flipping river.

[LuthieroftheDesertLoon]

Thanks grandcanyonminstrel for something to look at.
No idea why people have to be nasty at someone asking a mere couple of question.
Figured this was the place to learn.
Last and only post.
Life is short to deal with such a negative bunch of people.
So looking at grandcanyonminstrels post is talking about everything I asked and was wanting to know if anyone had any knowledge of this.
Thanks, I follow your postings and stay away from the rest.

[Walt]

Thanks grandcanyonminstrel for something to look at.
No idea why people have to be nasty at someone asking a mere couple of question.
Figured this was the place to learn.
Last and only post.
Life is short to deal with such a negative bunch of people.

Reminder that it's hard to convey tone on an Internet forum. It's easy to take things the wrong way. Marty's first post came across to me as thoughtful and encouraging, but I think you interpreted it as negative. Likewise, people may have interpreted your words about traditional builders as an insult, but I don't think you meant it that way.
This is a cool place to learn about building, and the amount of information these luthiers are willing to convey is basically unprecedented. I've been reading and posting here since 2002, and while I certainly haven't always held myself to this standard, I find it's a much better experience if I give other folk's posts the most charitable interpretation possible. Again, I'm no saint--I've been on the giving and receiving end of ill-tempered posts. But most of the time, when something comes across as mean on here, it was not intended to be.
Also, emojis help.

[LuthieroftheDesertLoon]

Wait. I stated i was and am a die hard wood worker.
I have nothing against traditional builders, never said that.
I again merely asked two Q's.
To me I don't personal get involved when someone asks a question
that doesn't pertain to my background, because I feel I have no valuable input on "That" subject

It goes along with someone telling you how "Not" to do things, instead of "Just telling them the correct way
to do it.
To much time wasted there in my view.
So again Personally I stick to what I know
and If I don't "Know anything about the questions asked I just stay away from it.
That's me personally.

[CarlM]

This is the last I am going to say here. You were rude and disrespectful in your initial posting and subsequently. If you did not intend to come off that way maybe reread your posts and ask how you would respond to someone who approached you like that.

Every single person on here has more experience and/or education than you do. Most of us have done wood and metal working professionally, not just as part time amateurs for many, many years.

Several answered your question either directly or indirectly and you have kept browbeating because you already know the answer you want even if it is wrong. Your approach is very similar to many 22 year old apprentices who have worked for me. They eventually outgrew it.

Go ahead an actually build a mandolin and show us.

[LuthieroftheDesertLoon]

and this is why others have many posts on the subject I was asking about.
I replied to you Carl with respect.
Your first post was insulting a question, then the Montana thing.
You know nothing of my background.
Again I was asking 2 question .
Nothing is black and white.
I'm not here to be disrespectful to you or anyone else
at the same time I'm not here to be disrespected.
I have no issue with clarifying something, and meant no disrespect to you.
But on the same token don't assume.
The links have been provided on the information i was trying to learn more about.
Best always

[Steve Sorensen]

I always find it interesting how much "Super Cars" look like regular Cars.

The difference is in the details, engineering, precision milling, and time invested in the materials, planning, and building processes.

Oh, and you have to also have a deep and intuitive understanding of the Driver's Needs -- otherwise you can build an amazing but worthless money pit.

I also find it interesting that sites like this have experts who build "Super-mandolins" who are willing to share information which ultimately seems to just frustrate and anger the people who want to quickly reinvent the wheel, ignore the accumulated wisdom of the experts, or find a short-cut to excellence.

As in the car world, most regular folks could not successfully build a Model T Ford, let alone build one component of a Konisegg One. But if you can't comprehend and build a copy of the simple production form, it is unlikely you will ever master the skills to build a real "Super" version.

There is a life-time worth of wisdom on this site for those who are willing to dig deep and do the real work of combining a wealth of existing knowledge with innovative thinking, tireless persistence, and hard work. Expecting those experts who have already walked this path to carry you to the destination is a tad bit immature, I think.

The proof of who you are is in the work, not the words. As Carl said, "Build a mandolin and show us!"

Steve

[LuthieroftheDesertLoon]

Ignorance people.
Look at the post.
I stated I'm not here to reinvent the wheel.
Never said anything against traditional builders, consider my self in that line.
Asked 2 questions that pertain to the building of a sound board to gain knowledge
before assembling the instrument. SIMPLE...Not I guess.

So every thing else except what I was asking about along the way.
Yet grandcanyonminstrel answered it in one post.
com on folks.
Please I don't need anymore replies to this, at 60 it's taken way to long as it is.
I know now who to follow and get information from
This is not meant to others who posted links to follow.
I appreciate that and learning.

[sunburst]

...SIMPLE...Not I guess...

Bingo!

[peter.coombe]

Well I thought I answered your specific questions in my first post, but you did not want to know the answers. John is right, this stuff is not simple.

grandcanyonminstrel's method is a really great idea, I like it. You can learn a lot in a relatively short space of time with his setup. It has it's limitations, like most testing jigs, but appears to work well.

Opening up another can of worms, but subjective evaluation of musical instruments is a mine field. One could validly argue that the ear is the ultimate measurement tool, as grandcanyonminstrel has, but human hearing is notoriously unreliable. Research has shown that reliable hearing memory has a very short lifespan of just a few short minutes. So when evaluating musical instruments with your ears, it is very important to have a known reference that does not change. We all use our ears, there is not really any other choice. Measurements are reliable, but we don't know how they are correlated to what we hear. It is very easy to get fooled if you rely on memory. With subtle changes it is also easy to get fooled if something is not quite right, such as a string slightly out of tune, or intonation is slightly off. I have been fooled many times, which is why I always keep coming back to make the same comparisons with the reference many times over. Some of the violin research has certainly shown up how easily people can be fooled. Many funny stories there.

[LuthieroftheDesertLoon]

Peter,sorry I did not mention you by name, but I said for those who sent me links (you( I appreciated that, and I do.
I appreciate anyone willing to give their time and being open to others ideas.
I'm now finding many people talking bout this same subject I asked about.
Again not here and was never my intent to be disrespectful to anyone. and I'll say right now that I'm sorry if I came across that way.

I've been a wood worker most of my 60 years.
I've been a singer/song writer since 1988
I've lived all over the US playing and singing
Attending workshops and putting on workshops
I personally know a lot of great luthiers, I worked at Elderly instruments
and know a lot of great musicians.

So again, Sorry to anyone who thought I was not being respectful
with this said I don't stand by when I feel disrespected by anyone as well.
Peace

[Marty Jacobson]

These guys pop up every so often.
There was the one a few years ago who claimed because he'd built a chicken coop he knew how to build a mandolin better than anyone else. And took any real advice as a personal slight.
What you gonna do.

[j. condino]

I think everyone would agree that I've never been afraid to voice my opinions and I lost count of how many people have told me what I was up to was a "Whole lotta nuthin'..."

If you are a crusty crusty traditional person, pick a traditional instrument and do your best to clone it. There are plenty of resources on how to do exactly that. The results may not be perfect, but they have proven to be similar. With tradition, you already know the model you are striving for. You just have to build up enough instruments and experience to get the subtle details down.

If you are a curious, creative person, follow your heart. The biggest challenge for the curious is that you first have to decide what it is you really want to say to the world and devote your time to. Then you have to figure out how to build it and make a great version of it.

Within this thread are some of the finest builders in this craft- brilliant minds and extraordinary skills. What all of them are trying to say is simple; turn off your computer and start building. You'll make mistakes, you'll have successes that will have you screaming out loud in the middle of the night wishing someone somewhere in the world could understand what just happened. Along the way, you'll learn a lot of important life lessons that have nothing to do with mandolins but are cherished.

If there was anything I could say about the mandolin cafe community is that some (many?) of us can come off like huge a$$holes on the computer, but wow- they are some of my best friends and nicest people I know when we get together in person! Good luck to all and have a safe holiday....

j.

[Tavy]

Interesting discussion

To answer the original question - I have fine tuned things by adjusting the size of an oval hole. However there are a couple of things you should know:

* adjusting/shaving braces has next to no difference on the top mode frequencies - you can free up or close down some modes by adjusting braces, but the actual frequency is largely determined by plate size IMO.
* Opening up sound holes has only a small difference on main body resonance frequency - which is to say you need to make a big change to make a small difference in frequency. Easier to drop a sound port or 2 in. Not much room on a mandolin side for big holes though, so again, you can shift the resonance up a couple of semi-tones but not too much more.
* Given the above - get the basic design right first - body width and depth so that the frequencies are all in the right ball park to begin with. Mandolins are the way they are for a reason.

All this essentially gives us 2 traditions:

* Classical: narrow stiff but light top, with deep body and small soundhole (eg bowlback). Body resonance is below the bottom G, sound is bright and sparkly for cutting through the orchestra. Not much bottom end.
* Gibson oval: body not too deep, smallish soundhole. Body resonance is typically somewhere near the bottom G and doesn't interact much with the main top resonance. Traditional Gibson-style oval sound. Can be tubby/boomy on the bottom, and/or weak in the middle if you're not careful.
* Modernist: larger soundhole, and/or soundports as well. Moves the body resonance up into the B-D region where it starts to interact with the main top mode and broaden out. Lovely woody "sound of moving air" on the bottom end, but can get wolf notes on those resonances if you're not careful.

In short, nothing is completely perfect, and it largely depends what sound you're shooting for and/or personal preference which style you build.

[hank]

ALERT: The reading of this material should be done wearing proper cranial moon protection. Luthiery and lunacy have been found to be coupled by free radicals on the surface of freshly prepared mandolin infected brains. A more common mutant brain disorder M.A.S. has been attributed to this virus and moonshine as well but without the devastating conclusion jumping symptoms of Luthiery lunacy.

[Stephen Perry]

I am not certain but I suspect that with the greater forces on a mandolin top there is not as much latitude to change arching and neck angle without collapsing the instrument. That is just speculation though and would be interesting to investigate.

I've seen some distinctly different than standard arching on a couple of highly acceptable mandolins, which is what got me thinking.

Mandolin arching usually approaches a dome with the sides cut out, leaving a long domed arch that broadens at the ends, weakest between the upper F hole eyes. This isn't a rational engineering choice. Violin arching in the more or less (varies, to put it lightly) standard Cremonese style is more like two domes connected by an almost cylindrical conic section, relieved at the sides. Violins swell at the waist, so somewhere between the center line and the ribs in the waist area there are straight line segments that usually diverge toward the endpin and often lie about where the bridge feet are. This is much different from the dome of the mandolin. That central plateau in the violin, between the F holes plus a bit, is quite a bit different in shape from that of the mandolin. The behavior of that central plateau and control of its support north and south of the F holes occupies violinmakers a good deal. I don't see the same attention reflected in the mandolin world.

Interesting to consider.

[LuthieroftheDesertLoon]

Thanks Tavy, much appreciated.