sound hole

chuck in ny

Well-known member
Joined
Feb 2, 2013
Messages
528
Reaction score
0
is there a good acoustic reason why a sound hole has to be on the face of an instrument rather than the side?
 
Depends on where you want the sound to be clearest.
The tone tends to be best perpendicular to the hole.
So, usually the hole is in the front, because it's designed for an audience that in theory is in front of you.
But then some ukes have side ports so that the sound goes up to the player.
Some luthiers are experimenting more though and challenging that.
There's a boat paddle with only side ports.
And then there's that tahitian that has the hole in the back.
Oh and then some artificial ukes have ports in the neck.

Try plucking an open string while looking into the hole.
Then turn it away from you and pluck it again.
 
Last edited:
spook

okay i did the string pluck test, hole towards me and hole away. there is a difference of course, some nice overtones are particularly present with the hole towards me. however it wasn't bad at all, different, almost more acoustically balanced (?) with the hole away from me, the volume at any rate was fine. short story long i think you can put the hole in different locations and as you wish. jmo.
 
I have a student with a sound port on the side and it gets a lovely sound, whether I am holding it, or sitting across from her. It definitely feels more "live" (is that the word I'm looking for?) when you are holding it and the port is right under your face.
 
jenny

i am planning a couple of builds and think to put the ports on the sides. not only acoustics, a matter of industrial design. interesting subject to say the least.
 
From what I understand, the real "tone wood" usually exists in the front, or top of the uke. It can have different vibratory characteristics. I just had a side sound hole (facing up towards my face) cut into my all laminate uke, and wow what a difference. It doesn't sound quiet anymore.
 
jenny

i am planning a couple of builds and think to put the ports on the sides. not only acoustics, a matter of industrial design. interesting subject to say the least.

I think they definitely can look lovely. I'm trying to remember if the uke I mentioned also had a sound hole on the front. I think it does. It is a Peavey, and was pretty inexpensive. It has a very sweet sound and may be my favorite sound for a laminate so far. I think there is a teardrop sound hole on the front, above the string line, and then one on the side, on the lower bout.
 
I have 2 guitars and a bouzouki with side sound ports and all sound great. It's impossible to A/B them as there are no identical instruments, or even similar ones as these are one-offs.

However, there is a point of diminished returns it seems. One of my guitars started with one port, then I had another added by the builder which did nothing for it but weaken the tone, then had the second one closed and it returned to normal. Sounds better with one port than two.

I've never tried to add a side port to an ukulele. Maybe it's time to try it on something I don't value so much.
 
The soundhole does basically two jobs:
- lets out vibrations from the inside of the soundbox/underside of the soundboard
- loosens up the soundboard so it can vibrate more easily
On top of that, some believers in soundbox tuning say it can also change the base key of the instrument.

Soundports and alternative soundholes have been done on guitars as well, mainly for reducing feedback from electric amplicifcation:
- smaller 'adamas'-soundholes on Ovation and Applause (and Applause ukes),
- slit-style soundholes on Washburn instruments (and the Kala HH bass ukulele),
- teardrop soundholes at the side of the upper bout on Tacoma instruments (including the Tacoma Papoose, an octave guitar, and the above mentioned peavy)
- blind soundboard on Alvarez Yairi guitars (and some 1920s Lyon & Healy camp ukes)

An entirely closed soundbox would be a bad idea for acoustic instruments, because it would inhibit most movement of the top. Such 'chambering' is however used on electrical instruments that need some 'acoustic sounding' amplified quality.
 
The soundhole does basically two jobs:
- lets out vibrations from the inside of the soundbox/underside of the soundboard
- loosens up the soundboard so it can vibrate more easily
On top of that, some believers in soundbox tuning say it can also change the base key of the instrument.

Soundports and alternative soundholes have been done on guitars as well, mainly for reducing feedback from electric amplicifcation:
- smaller 'adamas'-soundholes on Ovation and Applause (and Applause ukes),
- slit-style soundholes on Washburn instruments (and the Kala HH bass ukulele),
- teardrop soundholes at the side of the upper bout on Tacoma instruments (including the Tacoma Papoose, an octave guitar, and the above mentioned peavy)
- blind soundboard on Alvarez Yairi guitars (and some 1920s Lyon & Healy camp ukes)

An entirely closed soundbox would be a bad idea for acoustic instruments, because it would inhibit most movement of the top. Such 'chambering' is however used on electrical instruments that need some 'acoustic sounding' amplified quality.

re the movement of the instrument top. is there any inherent advantage in the usual one large hole, or would a series of small holes, or a long slit, do as well, and would the placement of these be best long ways, with the grain.
edit. just looked at the tacoma pappoose. the sound hole is off in a corner. it's hard to visualize that this would have an appreciable effect on loosening up the sound board.
 
Last edited:
Can you explain this? What is meant by bass key, exactly? I'm interested to know. The science of acoustics is amazing.
I think they're referring to the Helmholtz resonance frequency of the soundbox. This is the frequency that will have the largest amplitude response to vibration. Usually this will be at a slightly lower frequency than the lowest note that will be played on the instrument.
Having the peak response within the range of the instrument can lead to problems like "wolf notes", where one particular note is much louder than others.
 
I have a student with a sound port on the side and it gets a lovely sound, whether I am holding it, or sitting across from her. It definitely feels more "live" (is that the word I'm looking for?) when you are holding it and the port is right under your face.


grabs Pono a hammer and a chisel. :D
 
I think they're referring to the Helmholtz resonance frequency of the soundbox. This is the frequency that will have the largest amplitude response to vibration. Usually this will be at a slightly lower frequency than the lowest note that will be played on the instrument.
Having the peak response within the range of the instrument can lead to problems like "wolf notes", where one particular note is much louder than others.

True! I meant 'base key' but typed 'bass key'. Not the entirely same.

Helmholtz resonance would be better: goes down when the soundhole gets larger, up with a smaller soundhole or fewer soundholes. Just tap a cardboard box while opening or closing the lids to understand it.

It's a long and interesting theory in instrument building.
- Start with the idea of tap tuning the soundboard and back. Some luthiers say they strive for a particular note, others just for maximum resonance of whatever note. If they go for a note, some say it has to be the same for top and back, some pick out two different ones.
- Then put the box together and the inside volume plus size of the openings gives another note - again some luthiers try to get it to a particular note to this 'wooden drum'.

Interestingly, if luthiers do strive for a note it's NOT one found in the open strings of the finished instrument (violin, guitar, ukulele, take your pick) but usually a quarter note off - to avoid strange overtones, so-called 'wolf notes'. Some claim Stradivarius tuned his violin boxes to an F# resonance, some say Loar made his mandolin boxes to a C resonance.

And some, like me, take it all with a grain of salt.
 
I have one uke I bought directly from China with two side-by-side sound holes on the top and it has better projection than most of my single front sound hole ukes. This discussion is making me wonder about adding a side port to my Lanikai just to see what that does.
 
Last edited:
not sure the projection is because of the 2 sound holes.
I think it's not as straight forward as just making a hole.

I removed the pre-amp from my Kala TEME3, which puts a hole in the side, because it was a non-destructive way to see what would happen. In a nutshell.. nothing really happened. It did not project more up or out. The pre was installed in the lower bout though... so an upper bout hole may be different?
 
As a live sound engineer, a sound port on the top side of an 'ukulele is problematic. It bleeds into the vocal microphone and adds another factor to audio feedback. While I can adjust my boards around that, it detracts from the natural 'ukulele sound. Ric
 
As a live sound engineer, a sound port on the top side of an 'ukulele is problematic. It bleeds into the vocal microphone and adds another factor to audio feedback. While I can adjust my boards around that, it detracts from the natural 'ukulele sound. Ric

With that information, I'm not going to add a side hole.
 
As a live sound engineer, a sound port on the top side of an 'ukulele is problematic. It bleeds into the vocal microphone and adds another factor to audio feedback. While I can adjust my boards around that, it detracts from the natural 'ukulele sound. Ric

So would that be the natural fluorocarbon or natural nylon strings? Pick that instrument ripe from the ukulele bush? Amplified by the natural mikes and electric amplifier... ?

Just pulling your chain a little here, Ric ... (That "natural" word sometimes pops up in places that don't seem, um, well ... Natural ...)
 
Top Bottom