Decisions - scratch build 7 string, string spacing, scale length, pole-to-string and lots more..

[dmlinger]

What tools do you currently have or have access to?

 

[pondman]

Just get stuck in.

 

[NickK-UK]

What tools do you currently have or have access to?

Bandsaw - an old Ryobi 3080 - just waiting new tyres for the wheels. I have blades and bought a new one for the cuts.
Router (1200W 1/4") - with the required bits including a set of new bits with bearings) - this includes a 6mm bit for the truss rod
Jigsaw
Circular saw (converted to a makeshift saw table)
Overengineered DIY'd 2x4 based work bench - removable metalwork vice and customisable if required. Able to take an engine block.
Chisels (various exceptionally sharp) + mallets
Manual Planes (a small smoothing and a fore plane)
Power plane
Drills - hand and sds (has non-sds mode)
Floor standing drill press (adjustable speed ratios)
Angle grinder (4" small size)
Tenon Saw
Rip Saw
Claps (various sizes)
Calipers
Squares - numerous
Metalwork files
Wood horses
Spirit levels (although these won't be flat enough)
... and a shop vac

I will need to get (at a bare minimum):
* proper flat edge
* fretboard saw

 

[NickK-UK]

Just get stuck in.

I hear you "come back when you have cut wood and messed something up!" By nature I'll analyse something almost to death. However in parallel the case is coming along and I have basically come up with the dimensions so I think this weekend will end up cutting wood proper.

 

[JimF]

I'd recommend getting a Japanese saw rasp as well.
Linky link

 

[dmlinger]

I hear you "come back when you have cut wood and messed something up!" By nature I'll analyse something almost to death. However in parallel the case is coming along and I have basically come up with the dimensions so I think this weekend will end up cutting wood proper.

It's good to analyze and plan out a build, so don't sweat that. It really is a "school of hard knocks" because all the planning in the world won't prevent you from making mistakes. It's part of the fun.

I've never built a neck through but I can imagine doing so without a power plane would be difficult. Especially when milling the wood to thickness to ensure you've got parallel front and back sides. It will also make your life way easier when getting the multi piece neck down to size.

A jointer and planer were, by far, the best pieces of equipment in my guitar building journey...even more so than CNC. Because without those tools, it's really hard to start from a good place. you need square and parallel blanks for guitars.

 

[NickK-UK]

Just glued the top on the case so that will be ready shortly to take the wood during the build.

I've been looking at jointers specifically rather than thicknesser (although you can get them combined). The cheaper end of the market are really swamped with products that can't adjust they in/outlet tables and don't have flat boards etc. I'm aware that you need the tables to get the flatness and straightness from the jointer but the thicknesses can't correct wood geometry, only thickness. Most seem over £1000 which is a little than my budget.

I think for this build it's just going to be a running board and manually planed.

 

[Asdrael]

The kicker is also that in "cheap" jointer/thicknessers, the snipe is usually terrible, forcing you to either work with longer pieces (ie more expensive) than you'd like, or make each time a sacrificial board.

I would rather encourage a decent jointer and a sanding thicknesser instead.

(I was lucky to have a very friendly pro woodworker next to my place doing the planning and thicknessing on their machine in 5minutes to perfect results... theirs costs like 35k tho)

 

[dmlinger]

I had great results with a Wen 8" bench top jointer ($400 I think), and a 13" DeWalt planer which I paid around $450 for on Black Friday years ago. Not chump change when you start adding up cost, but not crazy expensive compared to the top end stuff. Being able to joint each half of a 2-piece body blank was so helpful.

 

[NickK-UK]

Oh dear.. I think I've just convinced myself to move from a 27" to a 272.72mm or 28 5/8th scale due to the better alignment with the frequencies of the open strings in standard tuning (or even drop A).

 

[Asdrael]

Unless you plan on doing 0-00-0-00 a lot, it would be much more efficient to research pickup placement in relation to scale length. It will have a major effect on tone, whatever fret you play

 

[NickK-UK]

That too has not got past me.

Theory.. is the neck pickup sits under the peak amplitude for maximum output, with fretting those node positions change and so the response changes. Now I hear about the 24th “node” but the string then sits over the top which seems odd.

I may write a python notebook to calculate positions and calculate the FFT across each.

Bridge pick up is all close up on the first lobe of each fret, question is how does “eq” of amplitudes impact the content.

You could move the pickup and see the response curve and harmonics.. string thickness changes that response and so too does the the fretting.. now mutiply that by the humpbucker positions around nodes.. lots of variables

 

[NickK-UK]

Just to add a nice article on pickup response: https://till.com/articles/PickupResponse/

 

[Asdrael]

In case you need a reference: the middle of bridge humbuckers on superstrats are usually positioned 6 to 6.5% of the scale length from the intonation line.

 

[NickK-UK]

In case you need a reference: the middle of bridge humbuckers on superstrats are usually positioned 6 to 6.5% of the scale length from the intonation line.

Just had a think about this - I could model this is octave, a maths language, which could then provide a 'map' across the area of interest for the pickups. Then apply a pickup response to it to give a ball park figure. It's not really horrific maths, just lots of variables. If you think of it as calculating a heat map of response and then aligning the pickup to give the desired best result.

Here's some of the variables:
* geometry - the strings and all the other components aren't at simple 90 degree right angles.. so it's all sines, cosines and tangents.
* scale - per string, with intonation correction
* fretting positions - from nut to 24
* straight weight and thickness (as weight/thickness = mass = energy and width within the pickup field of sensitivity)
* string tension - affects the displacement for the vibration
* string magnet pull as a constant
* sympathetic resonance - as the other strings will vibrate in sympathy.
* pickup field from the magnet and the geometry (position, pole spacing and frequency response)
* bridge/nut wood resonance

Now this is ignoring the plucking characteristic, which essentially causes a split string (and changes the heat map completely at the point the pick is in contact with the string).. so you could add that too based on your own personal geometry of your playing.

I think that's possible. Most can be worked out and then stored so it's then matrix multiplication then simply apply a phase correlation across the map for the pickup response. It will then give a picture where the peaks show the best response position.

 

[JimF]

This is all fascinating, and I'm excited to see the progress when the tools hit the wood!
One thing I'm curious about, is whether the "perfect response position" actually sounds good? If that makes sense.
Bad example, but if you edit a recording so it sounds perfect (timing and note lengths etc), the brain spots this and notices it doesn't feel quite human.
Perfect might not equals "sounds best".

Now I'm fully expecting to be wrong here as you clearly know your stuff, I'm more prodding for further explanations!

 

[NickK-UK]

This is all fascinating, and I'm excited to see the progress when the tools hit the wood!
One thing I'm curious about, is whether the "perfect response position" actually sounds good? If that makes sense.
Bad example, but if you edit a recording so it sounds perfect (timing and note lengths etc), the brain spots this and notices it doesn't feel quite human.
Perfect might not equals "sounds best".

Now I'm fully expecting to be wrong here as you clearly know your stuff, I'm more prodding for further explanations!

Agreed, the same is true with amplifiers and speakers.

The main reason I’m thinking this would be good is ensuring there’s no dead areas where we get cancellation etc.

I should have some proper updates with photos over the next week or two

 

[dmlinger]

Don't know if this helps simplify your math, but in actual practice (not theory) I'm pretty sure waves on a string are always sine waves because the nut and bridge are always at zero amplitude at those positions (because they physically cannot move). I studied this stuff almost 20 years ago so it's fuzzy in my brain and could very well be wrong.

 

[NickK-UK]

Don't know if this helps simplify your math, but in actual practice (not theory) I'm pretty sure waves on a string are always sine waves because the nut and bridge are always at zero amplitude at those positions (because they physically cannot move). I studied this stuff almost 20 years ago so it's fuzzy in my brain and could very well be wrong.

There’s a few optimisations are could make:
* only symmetrical distortion (as end points are tied, which means odd harmonics) but the magnet force results in an asymetric distortion (even harmonics)
* we can say we don’t have any travelling waves on the string.
* we can model the string displacement as a 3D symmetrical so we don’t have any rotating vibrations etc.
* don’t model and impulse that then decays etc.

I will cross reference against a set of designs simply to ensure it makes sense.

 

[NickK-UK]

Managed to have a play of a 27” PRS today, seemed normal size doing scales. Also managed to have a char with the younger member of staff who seemed quite at home talking about longer scale lengths and drop tuning.

So 27 still seemed playable. The poor strat with slinky 9 string droped to D tuning seemed not to be enjoying the experience and jow feeling like a toy.

Spent the weekend prepping in the garage, i bought a cheapy no.4 and block plane that needed lapping to get to flag and true 90 on the sides, built some sticks and almost finished a think pieces e running board. Annoyingly the bandsaw bits haven’t arrived yet.

Week after next should see a flurry of activity. I’ll order the final bits so I’m not waiting - truss rod, nut, strings, jumbo frets, some hide glue for the fretboard and some shellac/nitro. I’ll also order some final tools.