blown pitch

ecosteel

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Hi folks, I've just finished building my third soprano uke, having solved some of the building problems with one and two. I'm happy with the intonation and volume but all three share the same complaint. Some background; when I made my mould I increased the overall size marginally ie by a couple of millimetres all round, the consequence of which is that the pitch of the body when blown across the soundhole is a C. Open chords with a C in them sound really loud and the 3rd string really dominates. If I retune the uke up a tone the problem disappears. Presumably the blown pitch shouldn't be a C, I haven't got a standard soprano to hand so can anyone tell me what it ought to be. thanks in anticipation Steve
 
That is what forced me to sell an otherwise beautiful guitar. If you have the ability, changing the sound hole size can change that note. Hopefully you can get it a 1/2 note away from any standard note so that peak effectively disappears. This can be either bigger or smaller (assuming you can "tune" your soundhole by starting small and working your way up) or even by adding an internal tube the diameter of the hole so the hole looks something like this [ This works sort of like a tuned port on speakers and if you can't reduce an already cut hole, it might be an option as a retrofit.
 
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thank you

Thanks Dave what a super idea. Definitely worth some experiments. If I can model the hole size I can save my mould as well.
 
I tap tune when I'm building. If the body resonance is to close to a note, I will enlarge the sound hole to avoid the wolf notes.

Brad
 
I'm not sure how tap tuning frequencies differ from the acoustic resonance he's experiencing, but they all play a part. Either way playing with the soundhole size seems to be your best bet at this point unless you want to resize your mold (not likely) or change the depth of the sides on the next one (Hmm...) I would think deeper sides would lower the resonance and shallower would raise it, depending on what way you want the note to move.
 
dave,
is there a formula to calculate how much area to cut out for the shoundhole
so that all the 4 srtings would sound the same (or almost) in loudness?
 
Hi folks, I've just finished building my third soprano uke, having solved some of the building problems with one and two. I'm happy with the intonation and volume but all three share the same complaint. Some background; when I made my mould I increased the overall size marginally ie by a couple of millimetres all round, the consequence of which is that the pitch of the body when blown across the soundhole is a C. Open chords with a C in them sound really loud and the 3rd string really dominates. If I retune the uke up a tone the problem disappears. Presumably the blown pitch shouldn't be a C, I haven't got a standard soprano to hand so can anyone tell me what it ought to be. thanks in anticipation Steve
What thickness is the top back and sides?
 
Interesting! This board is great for learning new things! :shaka:
 
dave,
is there a formula to calculate how much area to cut out for the shoundhole
so that all the 4 srtings would sound the same (or almost) in loudness?

Oh, I wish it was that easy.

There are some books on acoustic theory out there somewhere. A good general overview is Bart Hopkin's "Musical Instrument Design."

I think in general you're looking for a "tap tone" and "body resonance" to each be different notes and neither of them exactly on any playable note on the finished instrument. What those notes are, and how to do it, is an artform in itself. You don't want any sharp resonant peaks, but rather a soft, neutral spread of sounds so the body contributes to all notes equally and not shout out on any one note.

I enjoy reading about building and acoustics, but it'll take someone with more "hands on" experience to give you more details than that.
 
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You do not need to be very far off of whole notes to be effective. An interesting bit of history, Lloyd Loar tap tuned his mandolins to exact whole notes as he built them. At the time they did not sell well. Concert pitch at that time was A=428 hz. When concert pitch was changed to A=440 hz. his mandolins started sounding really good.
Brad
 
I had an old Skylark Uke some years ago that had problems like this and I remember experimenting with a Violin type "Sound post" under the bridge, the idea was to help add more sustain to the quiet/dead notes.
 
You prbably don't want to hear this: 'What's the point?' If I was building a $5000+ instrument I just might be concerned about this but other than that, it's a ukulele for crying out loud :eek: If you have built it cleanly and nice and light with a slight graduation of the top you should be there. Tap tuning? Bit of a wast of time and energy for this type of instrument. With a 'carved' instrument the plates must be tuned for it to work! When it gets to a violin then you really are in critical territory. Now call me reactionary - are you comparing the humble ukulele which is one step away from a 'folk' instrument to a concert violin? I hope not because I just might be constrained to use the word fatuous without prejudice :smileybounce:.
 
You prbably don't want to hear this: 'What's the point?' If I was building a $5000+ instrument I just might be concerned about this but other than that, it's a ukulele for crying out loud :eek: If you have built it cleanly and nice and light with a slight graduation of the top you should be there. Tap tuning? Bit of a wast of time and energy for this type of instrument. With a 'carved' instrument the plates must be tuned for it to work! When it gets to a violin then you really are in critical territory. Now call me reactionary - are you comparing the humble ukulele which is one step away from a 'folk' instrument to a concert violin? I hope not because I just might be constrained to use the word fatuous without prejudice :smileybounce:.
Yup! just play it and sing along and be happy..Thats what it's for :cheers: just entertainment.
 
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