Shape of F holes and sound

[Dr Rod]

I was wondering how the different shapes and positions of the F holes affect the sound. Especially as far as the low end is concerned.

My curiosity was aroused by these basses:

http://www.gruenert.com/gruenert_eng...e/solobass.htm

http://www.poellmann-contrabass.de/b...nezia/main.htm

[ZombieGhosTrain]

The F-holes are just there so air can move in and out, taking sound with it. As long as the holes aren't too big or too small as to let too much or too little air through, I don't think it would make a difference. The F-ish shape might be an old tradition, and those look kinda cool.

[anthem274]

Correct me if I'm wrong, but I remember seeing a video where a luthier took a freshly cut top of a violin (no f-holes), and put sand all over it. He then played music under the top through a speaker and all the sand collected in the spots where the f-holes are cut.

[jneuman]

Theoretically, holes with equal air volume (top thickness times hole area) will produce equal performance. In reality, Shapes affect tone because of the different resulting distruption in the top modes and also losses due to the pumping of the air piston at the holes. Shapes which have greater perimeter length for a given area should provide better performance I think.
-Jon

[Matthew Tucker]

In his "Traite de Lutherie" 1974 , Andre Rousel (Mirecourt, Paris) wrote that thinning the upper languette (the upper "tab" of the F) makes the high notes brighter, to a point. Conversely, that the lower languette has no effect on sound as it is not connected directly to the vibrating table.

Of course, like so many other theories about why violins work and so on, it might just be a load of cobblers.

[Eric Rene Roy]

Originally Posted by anthem274

Correct me if I'm wrong, but I remember seeing a video where a luthier took a freshly cut top of a violin (no f-holes), and put sand all over it. He then played music under the top through a speaker and all the sand collected in the spots where the f-holes are cut.

Sure, I'll correct ya!

You're reffering to Chladni patterns.

See here for more than you ever wanted to know about them:

http://www.google.com/search?num=100...tterns&spell=1

[JoeyNaeger]

I heard that one of the important roles of the f holes was to sever the grains running on either side of the bridge in order to make the top more flexible. I would imagine any shape would do as long as it accomplished this, but I wouldn't be the one to ask.

[anthem274]

Very interesting links. Thank you, Eric.

[Matthew Tucker]

Francois Chanot experimented with violin shapes and sound holes in the 1800s. he made a violin with no f holes on the top. He put sound holes in the sides to test the flex theory. It wasn't a roaring success. But not necessarily because it didn't work ...

But look at this link.

http://www.usd.edu/smm/Violins/1800-1849/Chanot2.html

Now there's a cornerless shape that to my taste is extremely elegant.



check out the tailpiece!

[Dr Rod]

Originally Posted by Matthew Tucker

It wasn't a roaring success. But not necessarily because it didn't work ...

so...the instrument actually sounds good, but people were closed minded?
I always thought that the F holes, or ports for a bass should be shooting downward towards the floor. If you look at speaker placement treaties, you will find that walls and flooring near the port will enhance bass response.

Originally Posted by Matthew Tucker

Now there's a cornerless shape that to my taste is extremely elegant.

check out the tailpiece!

I find the instrument very beautiful, how does it sound? what do you know about the tailpiece?

[spdrswb]

As I know, bigger sound hole, bigger low end volume. Up to the limit of top plate stability, of course.

Sorry, I didn't want to start a thread just because of it, but I liked that violin shape and I'm mesmerized by the old guitar shaped gambas and DBs. I think, Storioni did one and it was an Italian fashion generally. What is your opinion, what are the specific properties of these instruments acoustically, mechanically, at all?
- Does it mean any extra difficulty for the luthier?
- Is theere a noticeable sound difference?
- Is it sturdy enough?
- In other words, what corners give to stringed instruments?

Thanks.

[M Ramsey]

Morning all,

I know we're talking basses here, but I have a bit of stuff to add from the standpoint of mandolin building. About 11-12 years ago, I brought home enough wood to begin making a mandolin. The F hole, F5, Gibson styled type. I used the Siminoff book and there's a good bit of info about tuning the top of the mandolin prior to actually putting it together.

As the F holes (again on a mandolin) are opened up, the treble frequencies become more prevalent, to a certian point. Keeping those F holes smaller, produces more of a bass tone, maybe not MORE, but the maybe the treble sounds are not as easily heard.

This COULD apply to an upright bass, but I'm no expert. There are those here on the list who I think would have a much greater understanding of these questions.

Where's Nick Lloyd when you need him?

[Eric Rene Roy]

Originally Posted by anthem274

Very interesting links. Thank you, Eric.

and I am sure you saw this:

http://rogerbourland.com/redblackwin...atterns-video/

[Matthew Tucker]

Originally Posted by Matthew Tucker

Francois Chanot [...] put sound holes in the sides to test the flex theory.

sorry, wasn't Chanot. It was another french luthier called Auguste Tolbecque, a contemporary of Gand and Bernardel, who put the sound holes in the C bouts. He experimented with the size of the sound holes using cardboard and leather strips placed in the open C-bouts.

The result of his experiment, he diplomatically reported, was a louder and more resonant instrument, although the gain in loudness was not accompanied by a gain in the quality of the tone ...

He did mention in his book that the technique might be better applied to double basses, whose tone is proportionally not as strong as violins, and also because not having holes in the belly would strengthen the arch, which in a double bass has to support such huge pressure.

Not sure if I'm going to be the one to test the theory further though!

One of Chanot's mistakes was to put the scroll on a violin facing backwards for practical reasons, access to the pegbox. But it was so ugly, he put a normal on on his next model.

[Dr Rod]

Originally Posted by Matthew Tucker

the gain in loudness was not accompanied by a gain in the quality of the tone ...

...and tone is a subjective matter. Especially when it comes to the French school of lutherie, one has to remember that their ideal of sound, even for a bass, is with tons of overtones. They are not really concerned with the lower frequencies, so what for him was an inferior tone, might just be the right thing for us.

Thanks for your valuable info.

[Jake deVilliers]

There are a lot of variables involved in the size, shape and positioning of the f holes.
I can tell you that in my experience, opening up the soundhole on an acoustic guitar will definitely raise the Heimholz number, the resonant frequency of the air chamber, and bring out more of the higher frequencies all round.
A similar result occurs if you make the body of a similar guitar a little smaller while keeping the soundhole the same size. It also seems to help the projection.
I'm talking Martin style dreadnaught here.
If you really want to know more, try the Guild of American Luthiers (GAL) or the Musical Instrument Makers Forum (MIMF).

Take a notebook!

Seeya, Jake

[KSB - Ken Smith]

Today I was doing a photo shoot with my friend and Violin/Bass historian Duane Rosengard shooting my Martini and Prescott for future refrences. Duane mentioned that he had previously owned a 1926 Martini as mine was the earliest example we have seen from 1919. The upper sound holes/eyes on mine are tiny; http://www.kensmithbasses.com/Double.../martini14.JPG
The 1926 model having the same exact form but with the upper holes/eyes being larger but centered in the exact position. This brings the inner edge closer to the center of the top slightly.

1919 Martini; http://www.kensmithbasses.com/Double...ini_bass_2.htm

With the larger Eyes, the Bassbar HAS to be moved inwards a bit thus using a Bridge with less distance between the feet. Duane mentioned that my Martini had a more open sound than the 1926 model due to the 'allowable' bass bar position. Also, by 1926 Martini was using more uniform wood and without knots unlike the 1919 model. We have all seen the old basses with knots and have learned to accept them.

So, if the sound holes are such that they dictate where the Bassbar has to be placed, this feature alone would in my opnion have the greatest impact on the sound differences between the f holes variations as sound coming out of the bass is dictated by how much sound the bass can actually make.

[KSB - Ken Smith]

Originally Posted by eroy

and I am sure you saw this:

http://rogerbourland.com/redblackwin...atterns-video/

Can you imagine playing a 3 octave scale with each bass and filming the patterns for each note and comparing them bass to bass or even same the bass with different bows?

Providing each note has a special shape pattern, can you imagine walking into orchestra 300 years from now and the composer writes the shapes as the new language of notation... Twilight Zone is where my head just went with this...

Ok, i'm gonna cool off not and watch a little TV before going to back to bed...

[Eric Rene Roy]

Ken, when I first saw that video, i was at the shop...and everyone quickly gathered around my laptop to see. Everyone was just floored. violinmaking regularly uses modes 1, 2 & 5...but I had never seen a full sweep like this video before.

We are in the process of making a bass in the shop now and took the opportunity to design our own. I started with the bridge...then the bass bar placement based on the bridge...and then built the bass around that. I think planning everything out this way is smarter than designing the outline first and then making everything fit that.

Related to ff holes...but also slighlty off topic...I know many violinmakers who weigh the belly of the violin before they cut the ff holes (actually, some of them obsessivly weigh everything). They do this because when they place the bass bar...they carve until the weight of the plate is back to what it was before removing the ff hole wood. Personally...I have never done this...but I think I may weigh my bass plates and just see where things go...even if it is just for my own observations.

[KSB - Ken Smith]

Originally Posted by eroy

Ken, when I first saw that video, i was at the shop...and everyone quickly gathered around my laptop to see. Everyone was just floored. violinmaking regularly uses modes 1, 2 & 5...but I had never seen a full sweep like this video before.

We are in the process of making a bass in the shop now and took the opportunity to design our own. I started with the bridge...then the bass bar placement based on the bridge...and then built the bass around that. I think planning everything out this way is smarter than designing the outline first and then making everything fit that.

Related to ff holes...but also slighlty off topic...I know many violinmakers who weigh the belly of the violin before they cut the ff holes (actually, some of them obsessivly weigh everything). They do this because when they place the bass bar...they carve until the weight of the plate is back to what it was before removing the ff hole wood. Personally...I have never done this...but I think I may weigh my bass plates and just see where things go...even if it is just for my own observations.

I have heard of an old LARGE Maggini Bass with the wood built up against the Bassbar and then saw the inside of the Gilkes. With the old/original Bar removed, I can feel a slight hump all around where the bar goes as if making a platform for it. Have you seen many Basses like this before?