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Post by lavaman on Jun 20, 2015 6:36:26 GMT
Great guitar, well done.
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Post by lavaman on Jun 11, 2015 23:51:01 GMT
Are you sure that you've got enough clamps???
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Post by lavaman on Jun 11, 2015 14:40:23 GMT
I think the square tubes will do fine. As you say there is a risk of making the neck too stiff for the truss rod. I like the fact that you're pushing back the frontiers of guitar design. Long may it continue.
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Post by lavaman on Jun 11, 2015 9:35:08 GMT
Hi Rob
Many, many years ago I was a design engineer working for Rolls-Royce aero engines. I did some work with carbon composites, but much of what I used to know is long forgotten. However, we can apply some basic engineering principles to guide your decisions.
In engineering terms, components have to be both sufficiently strong to withstand the applied loads and sufficiently stiff to control deflections. Guitar strings apply their load parallel to the neck, so the neck is, in engineering terms, a strut subject to bending and buckling loads. Increasing the stiffness of the neck increases its resistance to these bending loads. Stiffness is proportional to the product of EI, where E is the material's Young's Modulus, and I is the 2nd moment of area.
Young's modulus for carbon composite will vary depending on the fibre orientation, and the fibre to resin ratio. So it's very difficult to arrive at a precise figure. Also, there will be a difference in Young's Modulus between your proposed composite tubular section and the Stewmac rectangular neck reinforcement rods due to the unknown differences in material specifications. For your application, I suggest a conservative assumption that Young's Modulus for the rectangular Stewmac composite is, say, four times that of wood and your proposed tubular section is, say, three times that of wood.
I, the 2nd moment of area, is a factor to take account of the geometrical section. The (I) value for your 4 mm by 8 mm double tubular section is about 50% that of the 3 mm x 9 mm rectangular section. (Note, these figures are for the area of the reinforcement bars only and do not include the stiffness provided by the surrounding wooden neck)
So, in summary, my 'back of a fag packet' calculations reveal: - Wood neck E = 1 // I= 1 // Stiffness EI = 1 - Double tube composite reinforcement E = 3 // I = 0.5 // Stiffness EI = 1.5 - Rectangular composite reinforcement E =4 // I = 1 // Stiffness EI = 4
When I consider the overall value of the finished guitar, I think the extra cost of the Stewmac reinforcement bars is worthwhile.
Iain
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Post by lavaman on Jun 6, 2015 18:13:36 GMT
The lop sided approach might work - drink more red wine to find out. I'm no luthier, but the stiffness of a beam (such as a brace) is dependent on the cube (power 3) of its depth so I guess you could cut away a fair amount in places whilst keeping the width so as to maintain its lateral stiffness. Iain
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Post by lavaman on Jun 6, 2015 15:19:28 GMT
Rob
Good luck with the new guitars. Have you thought about reducing the stiffness of the bracing by using larger scallops?
BTW, if you want another douglas fir door I have one in my loft you can have for free
Iain
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Post by lavaman on Jun 5, 2015 15:42:07 GMT
I have a Sigma 000M-18, similar to the 000M-15 but with a spruce top. For the money they are very good value but they don't sound anything like a Martin. Mine's for sale because I can't get on with the narrow neck.
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Post by lavaman on Jun 4, 2015 13:04:36 GMT
I had a Brook Torridge walnut guitar - does that count as mainstream? I was tempted by a walnut Brook because they look so nice, but I stuck with my original choice of a cedar and mahogany Clyst. No regrets. Iain
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Post by lavaman on Jun 3, 2015 16:40:32 GMT
I've completed all of the lab tests now so I'd thought I'd let you know what it was like. For the ABX test, I played just 3 guitars. Again in the dark. I played one guitar (guitar A) for up to two minutes, followed by guitar B. I then wore headphones playing pink noise while the researcher checked the tuning of guitars A and B. He then handed me back one of the guitars and I had to say whether it was A or B. The process was repeated 12 times, using the 3 guitars. I found the easiest way to identify the 'sound' of each guitar was to just play three simple shapes on each test - an A7 chord (x07989) followed by another A7 (x05650) followed by a D7 bass run (200212). I also played hammer-ons on the first string and listened to the ring of the other strings. I found it easier to concentrate and to remember the 'sound' if I just played for 30 seconds rather than the full 2 minutes.
The whole ABX test was repeated on another day using the same 3 guitars. I scored 9 out 12 on the second test which I was pretty pleased with. At the end of the test my 3 guitars were revealed to be walnut, sapele, and Brazilian rosewood.
The final test was to repeat the very first test where you had to rate the quality of woods. The only difference was that this time you could see the guitar and were told what the wood was. Not too many surprises here, the maple back guitar was brighter than the others, the East Indian rosewood was warmer and more complex sounding and the mahogany was somewhere in between. The sapele was similar to the mahogany but to my ears a little brittle. The Brazilian rosewood was similar in tone to the EI rosewood but it was duller, quieter and lifeless. My favourite was the walnut. I can't think of any 'mainstream' guitars that use walnut, perhaps they should.
Sam hopes to publish the results of his research towards the end of the year. If you've got the time and live near Lancaster it's worth having a go.
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Post by lavaman on May 30, 2015 19:29:02 GMT
I got 10 Euros voucher last week for a review on a mic stand. Put it towards a K&K pickup this week.
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Post by lavaman on May 23, 2015 14:14:45 GMT
You've built a lovely looking guitar. Now comes the fun part; playing it all day and every day. I bet the more you play it, the more the guitar will open out. You'll also develop subtle nuances in technique to get the best sound out of it. Enjoy your truly unique guitar. I listened to the sound clips. On the single string scale runs, you can hear the other strings vibrating in sympathy, so the top is definitely moving. I suggest recording again in 3 months and comparing with what you've posted today.
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Post by lavaman on May 20, 2015 17:26:36 GMT
Guitar Wood Tests - Lab tests at Lancaster University
Hi
I did the first lab test today and thought I'd let you know how I got on. They have 6 Fylde Falstaff guitars, all identical apart from the woods used for the back and sides. The neck on each guitar felt huge. I like wide vee profile necks like on the Martin Vintage series but these were a full C section and felt a bit like a cricket bat to me. You play each guitar for a couple of minutes whilst blind folded with welding goggles. (could this become a new fetish?) You keep the goggles on while selecting the computer ratings too. The darkened room glows faintly green. I played extracts from three tunes, all in drop D, on all of the guitars to try to compare the differences between them. I'm a finger picker but I took along a plectrum to test with as well. After playing each guitar you are asked to rate them on a computer screen in a similar way to the online tests. You've still got the guitar on your lap when you do the computer rating so if you're not sure you can play a few notes to remind yourself of that quality.
The lab test asks you to rate a few more qualities than on the online test; about 15 or so. I can't remember them all but they include 'warmth', 'richness', 'tone (string) separation', 'balance', 'brightness' , 'sustain', 'projection', 'loudness' etc. I'm not sure if these terms will mean the same thing to different players, but I guess it will even itself out as more and more people do the lab tests. Another quality was 'playability'; which I felt was a bit odd as all the guitars were the same, had the same strings and were setup the same. I guess they meant 'how much do you enjoy playing this guitar'.
You then repeat the process with the guitars given to you in a different order to the first test to judge the consistency of your ratings.
I rated the Walnut and Sapele guitars as the best. This was an interesting result because during the online test I rated the Walnut as best and the Sapele as the worst! What do I know?
After the rating test you can play all of the guitars without the blind fold. Again, I liked the Walnut and Sapele, but I also liked the Mahogany and EI Rosewood. They're all good guitars, but I guess we all have different preferences to the different guitar sounds. A big surprise was that I didn't like the Brazilian Rosewood guitar at all. It seemed a bit lifeless compared to the others.
They recommend that you do just one test per day as your brain gets tired doing the tests. I know mine did, so I'm going back next week to do the ABX tests and will report back then.
Iain
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Post by lavaman on May 19, 2015 17:20:54 GMT
where are the nails? It looks seriously good, and I love the art deco radiator cover.
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Post by lavaman on May 19, 2015 6:55:33 GMT
It looks wonderful, stunning sound from the pickup. Enjoy.
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Post by lavaman on May 16, 2015 10:12:48 GMT
Hi R the FI think the Zoom H2 route is a great option. Alternatively, if you don't want to spend any money, try connecting your microphone directly into the pc MIC IN socket (pink socket on my pc) and record with Audacity. Or record onto cassette and during playback, connect the cassette unit's stereo line out socket to the pc LINE IN socket (pale blue)and record with Audacity BTW, your guitar does look a bit like Mr Potato Head. Iain
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