Anyone Studied Effects Of The Enlarged Soundhole?

[Big Martin]

OK, bizarre question time..

Has anyone done any serious study of Larrivee's enlarged soundholes effects by way of comparison, or (HUGE GASP!) enlarging an existing Larrivee.

A number of Martin owners have enlarged the soundholes on some Martins to get a broader "cone of projection" from their guitar.  Some say it is a more open, airy tone as well.  One of the more noted and respected "Martin expert" luthiers (and fine bluegrass picker), Bryan Kimsey even offers soundhole enlargement as a part of a suite of "hot rod" mods he does to high end Martins on which he works.

I was wondering if anyone has examined the effects of such enlargement on the -50 and -60 series that Larrivee makes?  Is bracing and all other construction the same on these guitars?    Has anyone read any comments from the Larrivees themselves about this change?  Would you comment, Matthew?  Jean?

OK, who is going to volunteer to enlarge the soundhole on theirs and give a comprehensive before and after report?

NEXT, sound ports in the side!

[sacredground]

I have an SD50, and I beleive it projects more than my LVBW. The bracing on the traditional series is also different: Forward Shifted Symmetrical Parabolic X-Bracing. This is the same kind of forward shifting that Martin uses to allow the top to vibrate more easily for the BIG sound. The traditional series SOUNDS different than the L's. To my ears its a great sound...just different. Only drawback is that there is currently no feedback buster large enough to plug this thing!

Anyway--its not just the large soundhole, but that and different bracing patterns working together.

[jimmyd]

I remember hearing about an opinion piece written by a known luthier, Dana Bourgeois maybe?, that discounts the effect of enlarged soundholes. I've also read somewhere that this current trend is inspired by those copying the vintage Martin that was owned by Clarence White and now owned by Tony Rice. The sound hole was enlarged on this unit to repair severe damage from hard strumming when Clarence owned it. It was too trashed to patch so they  enlarged to hole.  Unfortunately my memory is fuzzy on this issue so take these comments with a large grain of salt. Maybe there is more to it than that. I have a Mahogany dread with a sound hole thats a bit larger than normal. It is really loud.  

[tubeornot2b]

Actually the story goes that when Whites family bought for him, when he was a teenager, it already had the enlarged soundhole. The damage had been done by the original owner. White did have the fretboard changed to the one it has now, a Gretch blank. The new fretboard extends over and covers a portion of the soundhole. I have seen where Tony Rice thinks that the fretboard extension mitigates the enlarged opening to a certain degree.

By the way I do have a recently acquired '94 maple J60 with an enlarged soundhole. It is quite airy sounding. How much that has to do with the soundhole itself, is difficult to say.

[Papamonty]

I spoke to Dave at GuitarAdoptions.com about the braces.  If you look at the top of the OM in the traditional series, the enlarged soundhole forces the X-brace to be shifted downwards towards the lower bout.  The Larrivee website describes the braces as Shifted, not "Forward Shifted."  And according to an email I received from Brian Trepanier from Larrivee, "I do not know the effects of the larger soundhole beyond the volume and bass increase, but the folks at http://www.larriveeforum.com could probably give a good variety of opinions."  I now have an OM-60K and am still breaking it in so I don't hear an increase in volume and bass yet. 

Jon M

[PortHueneme]

I think this would be a very tough thing to test.
My SD-60 has a big boomy voice. I have always assumed it was as a combination of many things.
First a quality box, second the 12 fret neck moves the bridge to the belly of the top, the bracing is shifted, and the larger sound hole.
To me it seems logical that a larger sound hole would allow the top to move more producing more sound.
This would be like trying to close an air tight car door vs. having the window down a bit.

My Gibson tenor uke also has an enlarged sound hole and is louder than other tenors I have played. Again not sure if it the enlarged sound hole or the fact the uke is 80 years old.

[jeremy3220]

First a quality box, second the 12 fret neck moves the bridge to the belly of the top, the bracing is shifted, and the larger sound hole.

Are you sure? I thought the body was just elongated... thus the sloped shoulders.

As far as making the guitar louder, I think it makes the guitar ssound louder to the player. I don't know about overall volume though.

Here's a good discussion on the subject: http://p082.ezboard.com/ftheunofficialmartinguitarforumfrm2.showMessageRange?topicID=13286.topic&start=21&stop=37

[Big Eric]

Hard to say for sure.  The only real way to test would be to have Larrivee make a slope shoulder D with a "normal" sized soundhole.

It might be possible for someone to make a plug of some sort that covers up part of the existing soundhole on an SD to have it equal the dimensions of a smaller soundhole.  Bryan Kimsey experimented with that also years ago.  If I remember correctly, he used a coffee can plastic lid for it.

BTW, I also "opened up" a D-28 with a bigger soundhole a number of years ago.  While the guitar ended up sounding different, in that case, it wasn't necessarily better.  It actually lost cutting power in jams.  Sold it soon after.  Bryan gave me some good advice by e-mail back then.  It's when I was still active on flatpick-l.

[ducktrapper]

Some guy named Helmholtz had some ideas. Get back to us if you understand it. I have the OOO-50 and the enlarged soundhole just eats more picks! 

http://www.phys.unsw.edu.au/jw/Helmholtz.html

[NotRevGDavis]

 

[saffron_boots]

Enlarging the soundhole will lower the mair air frequency of the guitar. Normally, it's around G2. You will notice it when you play the G note on the 6th string and the surrounding notes: the G (or G# or F#) will seem quieter and not sustain as long. This is normal. Most builders, I've talked to, aim for this note to be F# as it's played less often. If you hum this note into the soundhole the whole guitar will begin to shake with the feedback.

Enlarging the soundhole shouldn't make the guitar louder. Quite the opposite. You've lowered the pressure differential between the soundhole and inside the body. Less pressure, less volume, less forward projection. Things will probably sound bigger and better in the immediate vicinity of the player however...

[UK Mike]

Helmhotz said the larger the hole the higher the resonant frequency.

[Blue in VT]

 

wow that makes my head hurt!!! thanks alot Gary....



Blue

[PortHueneme]

Are you sure? I thought the body was just elongated... thus the sloped shoulders.

The body is longer, but the bridge is mounted much lower too. I have some pictures in the picture thread "Family Feud"
You can see how much the saddle is below the sound hole on the two twelve fretters, the "SD" & "O"

[saffron_boots]

Helmhotz said the larger the hole the higher the resonant frequency.

Holy smokes, you're right! I compared what he said with actual experiments that Alan Carruth did and the results are at best, inconclusive. Al looked at various parameters including changes in main air (Helmholtz) frequency, top plate (soundboard) frequency, sound pressure levels inside and outside the box and had this to say (it's rather dizzying):

Going from the smallest hole, 71mm dia., to the largest, 89mm, raised the 'main air' pitch from 89.3Hz to 98.2, a couple of semitones, and the internal sound level jumped by 68% when the hole was enlarged. The top, however, moved with less amplitude at the 'main top' pitch when the hole was enlarged, with the accelerometer giving a signal that was 7% lower and the internal sound level being 19% lower at that frequency.

In the end, there simply was not much musically useable change made by enlarging the soundhole, at least on this guitar. Despite it's looks it's not a bad little box, with decent balance and tone. Perhaps a guitar that was more lacking in bass response would benefit more from enlarging the soundhole some. Unless the change in area was large I suspect there would not be a lot of difference percieved in the overall timbre, but the balance and clarity might both be enhanced.

[ronmac]

Another "of course it matters" but "does it really matter" discussion? 

While I was reading the first few contributions of this thread I was thinking that I was going to compose a reply that included the Helmholtz equation. Thankfully someone beat me to the punch and now I don't have to take the "geek" rap...

[Tony Burns]

I know the effects of the enlarged sound hole - I wasnt even looking at it when i first played my OMv60 all i noticed was that the sound was fuller almost like I had a hole in the side of the darn thing - i could hear it alot better than with a smaller sound hole my other guitars had - Jean Larrivee is a visionary genious ( in my opinion ) no other guitar sounds like this one - and essentially what i know is that the darn thing is hard to put down once you start playing it - im not judging it against other guitars , because its its own unique creature 

[Big Eric]

If nothing else, the SD-50/60 looks nice with the large soundhole.  Better, IMO, than the Santa Cruz 12 fret D.  Which has, if I remember correctly, a smaller than normal soundhole.

Of course, the SC also has a shallow body.  So that would also change the resonating chamber frequency. 

[swainsong]

Having played the L-03 and SD-50 side by each, and compensating the calculations of volume compared to  the size of the boxes and bridge placement, my scientific opinion concluded that the 4" sound hole produces a tighter, punchier, more focused projection while the larger sound hole is looser, less focused, but is also richer and fuller and has a natural reverb that sounds a bit like you're listening with your ear plugged right into the sound hole.

I like the latter so much that I asked my mentor about putting a 4.5" sound hole in the guitar I'm building, but he said that the sound hole is a tuned port and that I didn't want to mess with it. Adding a side sound port into the upper bout, however, allows certain frequencies to escape that would normally be lost in the overall voice of the instrument. It also divides the sound into a kind of stereo effect, provides a louder and richer sound for an audience in front of the performer, and also gives you that added reverby resonance. (It can cause phase issues if you're recording with a mic, though, but you can simply plug the hole for those sessions.)

Here is a great article by Tim McKnight about his scientific research into side sound ports:

http://www.mcknightguitars.com/soundports.html

I would describe the effect of the enlarged sound hole on the SD-50 as being a compromise between the standard 4" sound hole and a 4" sound hole with a side port. However, I think there is a bit more to the design of the 12 fret slope shoulder (and D-50 series) that lends itself to the advantage of an enlarged sound port, which might not work on other body shapes and sizes. But on the SD series, well, that unique sound is what made me ignore my budget limitations when I bought the guitar.

[NotRevGDavis]

wow that makes my head hurt!!! thanks alot Gary....



Blue

It was said in jest, if the guitar sounds good, better, louder or different so be it- too much tech takes away the soul.