Behind-the-bridge Pickup projects

Talk about modding or building your own guitar from scratch.
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Harrison
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Re: Behind-the-bridge Pickup projects

Post by Harrison » Thu Nov 22, 2012 8:46 pm

dang it now I want one of those so bad.

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Re: Behind-the-bridge Pickup projects

Post by natthu » Thu Nov 22, 2012 10:19 pm

WonderCouncil wrote:....Here is a picture I had mocked up that kind of explains it.
Won't that be defeating the purpose of the BTB pickup?... or are you only concerned with the portion of the strings between the two bars at either end of the Tele bridge plate?
You'd be losing all the potential sympathetic ringing of the strings between the forward bar and the guitar's normal bridge....

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Re: Behind-the-bridge Pickup projects

Post by Sinuata » Fri Nov 23, 2012 1:56 am

WonderCouncil wrote:That is freaking awesome Sinuata! I love to heard some sound clips as well.

I have a couple questions though...I'm getting ready to mount a Tele bridge exactly like you have. I'm curious how far behind the bridge you have the Tele plate set, and how exact you figured out where to place it to get the perfect 4th tuning.
Thanks, and I'll try to find time to whip up some sound clips today if I can.
My setup is incredibly simple compared to your diagram, which confused me at first. So your diagram makes it look like the stings are going under, and held down by, the front rod, but actually you say they're going over? So the purpose of the front rod is just to hold down the intonation screws, so that you can string under the saddles, and presumably get more tuning range while keeping a good break angle both over the front bridge and under the tele saddles? And the full string length between the front bridge & tele saddles is ringing? It's a good idea, but I'm not sure it's necessary...
Mine is just a TOM bridge and the usual tele bridge with no mods, strung up in the usual way (as if the front bridge were the nut). I was worried about whether I'd be able to get enough break angle over both the front bridge & the saddles but somehow it wasn't a problem -- you do need a decent break angle over the tele saddles, so a string-through bridge is better than a top-loader, but either one will do, and mine is actually a top-loader (at the moment). But the front bridge can have almost no break angle, and in fact less angle is probably better since we want ringing BTB -- it only needs enough break that the strings won't slide out of the TOM saddles. Having said that, my guitar has a shallow neck pocket with a big shim, so the bridge is pretty high, which helps.

Image

Yeah, the bridge height, intonation on the front bridge, tele bridge saddle position & height, and of course tuning pegs all affect the tuning in both sections of string, so changing one means retuning all of them until everything's just right, but it's actually not too bad.

So, calculating where to put the back bridge.... It's pretty simple but I'm not sure if I'll be good at explaining it.
Since the string is the same (same gauge and tension) on both sides of the front bridge, the pitch is simply proportional to the string length. Half the string length = double the frequency = same note one octave up; 1/4 the string length = 4x the frequency = same note two octaves up, etc. So, measure your scale length (distance from nut to bridge) if you don't know it. You can measure it anyway, with your bridge properly set up & intonated, for increased accuracy, although I didn't bother.
My scale length is 648mm (25.5", but I'm going to use mm; sorry ). Assume a string tuned to 110Hz, which is A2 (the normal tuning of the "A" string -- but that doesn't matter; the math is the same whatever the frequency; 110Hz just happens to be easy to remember).
Now you can use a frequency-to-note converter like this one to work out what pitch you'll get for different lengths of string. For example, if the BTB length is 100mm, we have:
648mm/100mm = 6.48
110Hz * 6.48 = 712.8Hz
which the frequency-to-note converter tells me is F5+35 -- pretty dissonant against A.
So you can start by positioning the tele bridge & saddles in different positions, measuring the distance the string will stretch between the front bridge & tele bridge saddles, and finding the rough range of pitches that will be available to you. Hopefully there will be well over an octave of range, so you can decide what pitches you want. Then use the math in reverse to figure out where to place the tele bridge here's a note-to-frequency chart for that.
Move the tele saddles to around the middle of their available range before measuring for the final placement to leave some margin for error -- as long as you're in the ballpark, you should be able to tune the BTB strings how you planned . Just remember to measure saddle-to-saddle.

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Re: Behind-the-bridge Pickup projects

Post by Sinuata » Fri Nov 23, 2012 5:06 am

Okay, here are some clips. The pickups are disconnected from the pots right now so I was able to record the isolated sound of both the neck mini-humbucker and the BTB pickup simultaneously, so you can compare them. They're all recorded direct and dry. Don't mind the shitty playing; they're just to demo the sound :blush:


some random strums both in front of and behind the bridge:
both pickups together
neck only
BTB only

and a couple of ditties. All the playing is in the normal in-front-of-bridge position so the BTB stuff is just sympathetic.
sway neck
sway BTB
sway both

cinnamon neck
cinnamon BTB
cinnamon both

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Re: Behind-the-bridge Pickup projects

Post by thegumbootman » Fri Nov 23, 2012 9:45 am

I love that! :w00t:

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Re: Behind-the-bridge Pickup projects

Post by WonderCouncil » Fri Nov 23, 2012 11:15 am

Sinuata wrote:So your diagram makes it look like the stings are going under, and held down by, the front rod, but actually you say they're going over? So the purpose of the front rod is just to hold down the intonation screws, so that you can string under the saddles, and presumably get more tuning range while keeping a good break angle both over the front bridge and under the tele saddles? And the full string length between the front bridge & tele saddles is ringing? It's a good idea, but I'm not sure it's necessary...
First things first, those sound clips are awesome! Very very good work man, better then I could have done hah.

You are exactly right in your thinking of the diagram I made. Looking at it again I did screw it up. You're correct though that the front rod would only be used to hold down longer intonation screws, and not the strings them selves.

The whole purpose or idea was based off the idea that the break angle of the strings over the BTB saddles would not be great enough to really affect tuning. So my thinking was that by running them underneath with longer intonation screws would allow for a greater range of tuning.

I think you solved it tho by have the BTB saddles higher up. But in doing so it lessens the break angle of the strings over the front bridge. If that makes sense....

For example, with the set up you have. If you were to say bring the low E strings saddle out (closer to the BTB pickup) you would lose any kind of break angle between the the BTB saddles and ball end. Either that or you'd have to raise the BTB saddle higher up to clear the BTB pickup.

I suppose a lot of it has to do with how high you have the front bridge set, and/or how far back you have the Tele bridge plate set.

I guess with my idea, I was looking more at keeping a steeper break angle from the front bridge. Which when you think about it, and as you said, would likely diminish any kind of sympathetic ringing BTB. Also with mine you'd have to keep the BTB pickup more or less flush with the bridge plate.

I suppose what it comes down to is the tuning range.

if you were to have your BTB low E string saddle closer to the BTB pickup, will the string still make contact (break) over said saddle? With out having to raise the saddle higher up.

It seems to work beautifully the way you have it set tho. So I applaud you for that. Maybe I'm just over thinking it. Making it more complicated then it needs to be. Wouldn't be the first time that's happened lol.

I'm going to have to read over your calculations a few times I think. Numbers were never my strong suit...doesn't help I just work up either :bored:

You efforts have inspired me none the less tho to plow a head on my sitar project.

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Re: Behind-the-bridge Pickup projects

Post by antisymmetric » Fri Nov 23, 2012 11:34 am

This is great, thanks for the sound clips. this thread has definitely got me wanting to do something where intonation is possible.
This is all I have so far, a Kay pickup crudely mocked up on my Jansen Jazzman. Sounds great, but not tunable of course. I've tried running the BTB pickup through it's own effects (just delays so far). Endless possibilities! 8)
Image
Watching the corners turn corners

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Re: Behind-the-bridge Pickup projects

Post by maximee » Fri Nov 23, 2012 12:12 pm

Great sound clips!
I've always wondered how this would sound. I really like it.
Thanks for posting :)

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Re: Behind-the-bridge Pickup projects

Post by percnon » Fri Nov 23, 2012 12:37 pm

Sinuata wrote:Okay, here are some clips. The pickups are disconnected from the pots right now so I was able to record the isolated sound of both the neck mini-humbucker and the BTB pickup simultaneously, so you can compare them. They're all recorded direct and dry. Don't mind the shitty playing; they're just to demo the sound


some random strums both in front of and behind the bridge:
both pickups together
neck only
BTB only

and a couple of ditties. All the playing is in the normal in-front-of-bridge position so the BTB stuff is just sympathetic.
sway neck
sway BTB
sway both

cinnamon neck
cinnamon BTB
cinnamon both
Really nice! If I were you I'd put a stereo jack in that guitar and wire the BTB p'up to the second channel so you can process it separately. It'd give you a great 'wall of sound' kinda thing.

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Re: Behind-the-bridge Pickup projects

Post by Sinuata » Sat Nov 24, 2012 5:39 am

Thanks for the positive responses; I've been playing with different tunings a bit more; tuning the BTB strings to a proper chord is really nice, and the BTB ringing in conjunction with an open tuning on the main strings works really well, too. Tuning a BTB string to a major third (+ 2 octaves) over the open string makes it ring out like mad. I plan to get some longer screws for the tele saddles and convert to string-thru to increase my tuning range, but first I'm going to work on a pickguard & wiring...

WonderCouncil, like I said, your idea is good and I hope you try it out. Everything you say is correct AFAIK but I do think that you'll find you don't need as much break over the front bridge as you expect, and you might actually end up wanting less break, to increase the ringing BTB when you hit the main strings. I've presently got the BTB saddle for the low E moved forward as far as possible (it can just barely get a perfect 5th) and it's still okay. I was surprised, too. The break angle behind the tele saddles seems to be more important, but I've still got a bit of room to spare there, too.

percnon, stereo output is not a bad idea and I think I'll do that; hopefully with a switch to enable mono output when I want it.

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Re: Behind-the-bridge Pickup projects

Post by WonderCouncil » Sat Nov 24, 2012 12:25 pm

Sinuata wrote:WonderCouncil, like I said, your idea is good and I hope you try it out. Everything you say is correct AFAIK but I do think that you'll find you don't need as much break over the front bridge as you expect, and you might actually end up wanting less break, to increase the ringing BTB when you hit the main strings. I've presently got the BTB saddle for the low E moved forward as far as possible (it can just barely get a perfect 5th) and it's still okay. I was surprised, too. The break angle behind the tele saddles seems to be more important, but I've still got a bit of room to spare there, too.
I'm just happy you could actually decipher what I was trying to convey hah. I agree with though and from the pictures it appears like your way of doing it works. That was my only concern...that you may get to the point where bringing the BTB saddle more forward, you lose contact with the string it self. Thus defeating the purpose of the saddle. I was thinking that you'd have to raise the BTB saddle so high that it'd end up being even with the front bridge. If that makes sense...but your pictures prove me wrong...which I'm more then happy about lol.

I may give my way a go for the hell of it but I can see where you're coming from with the break angle over the front bridge. If it's too steep it'll cut off potential overtones.

Either way this set up should be pretty interesting in sitar form. I'm curious, maybe I'll look around the web but how long is a guitar string? Like new out of the pack. The reason I ask, I'd like to place the Tele bridge as far back as possible. It's a string thru as well...and I'm concerned the strings may not be long enough to be strung thru and still get 3-4 wraps on the tuner post.

Of course I have no spare strings laying around hah. I'll have to dig through my drawer and see if I can find one or find the length online.

Once again, freaking awesome work man...and same goes for the math/measurements for the BTB tuning. Once I can figure out how to measure the scale length with this buzz bridge I'll be in business.

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Re: Behind-the-bridge Pickup projects

Post by michaeldwatson » Sat Nov 24, 2012 2:02 pm

Hey natthu any word on the faux stop plate? I'm looking forward to that haha

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Re: Behind-the-bridge Pickup projects

Post by natthu » Sat Nov 24, 2012 4:01 pm

michaeldwatson wrote:Hey natthu any word on the faux stop plate? I'm looking forward to that haha
I've received the pickup this week, so I just need to do some measuring and submit my specifications to Mr Rhoney for his next round of plate making (which he hinted might be soon) :)

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Re: Behind-the-bridge Pickup projects

Post by michaeldwatson » Sat Nov 24, 2012 4:53 pm

natthu wrote:
michaeldwatson wrote:Hey natthu any word on the faux stop plate? I'm looking forward to that haha
I've received the pickup this week, so I just need to do some measuring and submit my specifications to Mr Rhoney for his next round of plate making (which he hinted might be soon)
Oh cool! Well I can't wait to see it finished :)

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Re: Behind-the-bridge Pickup projects

Post by Telliot » Thu Dec 06, 2012 8:30 am

This is such a cool idea, I'm watching this thread very carefully! :ph34r:
The cool thing about fretless is you can hit a note...and then renegotiate.

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