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"Testing" a box for bridge placement

I've been searching through the articles on this site for information on selecting the position where the bridge should be. Obviously on an unfretted instrument you can move the bridge and experiment, but on a fretted guitar, once the frets are on and the neck is fixed that's it. You have committed yourself.

So is there any way to know on a box for box basis (not using formulas because I'm pretty sure that they are worthless unless you always use identical boxes) where the bridge should be to get the best results?

Now I've already done some test, but I don't know if they are the work of a visionary (don't laugh) or a pointless waste of time (odds on the latter). I was thinking that as far as the box is concerned it gets most of the string vibration through the bridge. If you want to simulate vibrations coming from the bridge can you use something else that will transmit vibrations and see (or rather hear) how they sound and make a choice based on that. I found a tuning fork and tried it at various places on three boxes that I intend to use soon.

The results from the three were quite different. Not surprisingly all gave the warmest and clearest sound in the centre of the box. The top one gave quite progressive results getting better quite gradually towards the centre. The left hand one was very even across it's width until right near the edge. The right hand one was a surprise as it sounded best right in the middle, tone falling off and getting soft of nasal even an inch away from the motif. Shame as I don't really want to put a bridge right on the motif but my tuning fork test suggests that it may be the best place.

So, finally, to the question. Has anyone done any tests - similar or otherwise - that give a good indication of where to put a bridge and that do not rely on ratios or formulas, but take into account the different characteristics of each box?

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Replies to This Discussion

Permalink Reply by MichaelS Country Boy Guitars on September 19, 2011 at 9:33am

LOL, a long time I think. I said the cbg's sound good, lets not talk about the builder ok. : )

Permalink Reply by Roadkill a.k.a. John Maw on September 19, 2011 at 9:37am

But Michael. We only have your word for it. Not that I don't respect your opinion, but it would be nice to have the evidence. You know you want to really.

Permalink Reply by MichaelS Country Boy Guitars on September 19, 2011 at 10:27am

Try this link John, it has 1 sound clip and a video, let me know if the sound is good. I have tried to video myself but have not yet been happy with the results, must be the equipment. Please don't make me stop reading this thread, its too much fun. By the way, the Padrons are done.

http://squierdesign.com/country_boy_guitars.html

Roadkill a.k.a. John Maw said:

But Michael. We only have your word for it. Not that I don't respect your opinion, but it would be nice to have the evidence. You know you want to really.

Permalink Reply by Mark Bliss on September 19, 2011 at 10:50am

Links dead Michael

Its cruel for John to taunt us after setting the post so high...........

Permalink Reply by Roadkill a.k.a. John Maw on September 19, 2011 at 11:36am

The link worked for me (possibly updated since Mark made his comment).

That's great Michael. In fact I'm sure I have seen it before, but good to be reminded of it and have another look and listen. I hope it has proved to be good exposure for you. Still, now you have the Padrons are finished maybe you have time for a bit of a practice.

Mark. I don't think I was setting the standard high so much as giving people something to laugh at and in the case of the double necker maybe it was more the novelty value. Who knows. Now. Where's that tuning fork?

Permalink Reply by MichaelS Country Boy Guitars on September 19, 2011 at 12:27pm

OK, been practicing on one of the new Padrons, got to break in the strings you know, now if only someone were there with a video camera!

But seriously, I toyed with the idea of the box test stick once but never made it, good idea for testing the box and the placement.

Another thing, has anyone noticed that if you pluck the strings at the 12 fret it sounds like a door bell like chime? Close to the bridge it sounds like a banjo some were in between nice like a guitar. Makes me wonder if middle of box is best or not?

Permalink Reply by Mark Bliss on September 20, 2011 at 12:28am

Link works here, I was on a wonky network, that may be all it was.

Michael, the sound bite sounds good but is heavily processed. Some more would be interesting. Just a suggestion!

If you are talking about where the string is picked, yes this is common and normal. Many players will effect the tone of their playing by moving up the neck or toward the bridge. It seems to be more dramatic with some instruments, but very noticeable, especially picking near a strings "node" (theres that word again) such as the distinct harmonic at the 12th fret area.

The bridge placement discussion and experimenting is interesting, but in all seriousness its just not going to be as simple as one perfect answer. One location may be perfect for one frequency and volume but a comprimise for all others for instance. I know I originally supposed middle of the box, but middle of the box might be very loud at some frequencys and diminished at others. Then theres other things to consider, box size, material and construction of course, but also next in line is likely to be the neck, mass, stiffness and attachment method.

I have a bunch of ultra geeky scientific method papers directly or indirectly related to the subject, But heres one typical view of the changes in dynamics at different frequencys. (It may have been presented already, I forget......)

http://www.kettering.edu/physics/drussell/guitars/hummingbird.html

Anyway, what is of interest here to me is that it shows not only the dramatic changes in the location of the top activity in relation to bridge location but that the whole instument flexes, twists and moves in different directions. And all of this changes with different materials, sizes and construction techniques. In the end the idea is to get a well rounded comprimise I suppose.

Theres also some (Perhaps less directly) related thoughts here:

http://www.toone-townsend.com/townsend/2009/12/neck-design-theory.html

Permalink Reply by Roadkill a.k.a. John Maw on September 20, 2011 at 1:59am

Funny that the issue of where the string is plucked should come into the conversation right now. I got a new amp the other day (new to me that is) and it is much more sensitive to where I play compared to when using the MicroCube, and this applies when playing three different instruments. In fact I found that I am having to shift where I play and also be more accurate in response to the sounds that I am getting from this amp.

Just one little bit of information about how much the neck can affect (or not) the sound of the instrument. Someone commented on the video that I put up playing the double neck Alibow, saying that he was sure the aluminium necks would contribute to the sound. I had a go at strumming it with my left hand not touching the neck at all and then with my hand clasped round it to damp it as much as possible. I will try it again with someone else here (preferably someone who is a musician), but I could hear no noticeable difference between the damped and undamped playing.

P.S. Mark. Those links are interesting. I certainly don't want an instrument that moves like the one in the Mode #1 illustration. That's what happens when you make your guitar out of damp cardboard. The bass in the second link looks really nice. Makes me feel like taking up the bass (well, almost).

Permalink Reply by MichaelS Country Boy Guitars on September 20, 2011 at 2:58am

Mark, glad you could get it to work. I have to ask Michael what he played it thru but I don't think it is heavily processed, it sounded like that when I had it thru my micro cube, he just plays it much better than me. As for the video, I'm not even sure if you can hear the cbg in that one. I sent one out friday that I should get a few videos from by a more souther style player, should be interesting and I will try to post a few of myself, if your ears can take it.lol

Necks, The material definatly makes a difference, holding or not holding I'm not so sure. I use black walnut and its great, my brother used some spanish ceder, at the advise of his lumber yard, and it was a bit dead compared to the walnut. John is the aluminum you used tempered? That would (might) change it some too. Or we could just put a stick in a box and have fun. lol again

Permalink Reply by Mark Bliss on September 20, 2011 at 5:23am

By processed I meant the effects, sounds like some reverb/echo combination.

No doubt they sound good Michael, I am not questioning that and wouldnt hesitate to buy one if that was what I was looking for.

It would be good to hear more of a range of sounds as samples though.

Do anything but the three stringers?

Permalink Reply by Ron "Oily" Sprague on September 20, 2011 at 7:32am

Mark Bliss said:

Link works here, I was on a wonky network, that may be all it was.

Michael, the sound bite sounds good but is heavily processed. Some more would be interesting. Just a suggestion!

If you are talking about where the string is picked, yes this is common and normal. Many players will effect the tone of their playing by moving up the neck or toward the bridge. It seems to be more dramatic with some instruments, but very noticeable, especially picking near a strings "node" (theres that word again) such as the distinct harmonic at the 12th fret area.

The bridge placement discussion and experimenting is interesting, but in all seriousness its just not going to be as simple as one perfect answer. One location may be perfect for one frequency and volume but a comprimise for all others for instance. I know I originally supposed middle of the box, but middle of the box might be very loud at some frequencys and diminished at others. Then theres other things to consider, box size, material and construction of course, but also next in line is likely to be the neck, mass, stiffness and attachment method.

I have a bunch of ultra geeky scientific method papers directly or indirectly related to the subject, But heres one typical view of the changes in dynamics at different frequencys. (It may have been presented already, I forget......)

http://www.kettering.edu/physics/drussell/guitars/hummingbird.html

Anyway, what is of interest here to me is that it shows not only the dramatic changes in the location of the top activity in relation to bridge location but that the whole instument flexes, twists and moves in different directions. And all of this changes with different materials, sizes and construction techniques. In the end the idea is to get a well rounded comprimise I suppose.

Theres also some (Perhaps less directly) related thoughts here:

http://www.toone-townsend.com/townsend/2009/12/neck-design-theory.html

</
If you think all this is kewl (I know I do, and thanks for the links, Mark!), y'all are gonna absolutely love the discussion about papier mache' guitar building over at Homemade Resonator Boxes 101, v.2 . Ask Michael, he's been participating. The Dubman tester showed up over there, too.

Permalink Reply by Roadkill a.k.a. John Maw on September 20, 2011 at 10:21am

Mark.

Thanks. Your mention of nodes has just helped me realise something. I was wondering why sometimes my harmonics didn't sound good and at other times the did. If you try to pluck a harmonic at a node it won't work because that is part of the string that is trying to stay still, and therefor allow the harmonic to ring at the right pitch. If you pluck where there is no node (such as half way between nodes) then the harmonic rings loud and clear. Either I have just made a useful discovery (a personal discovery because I didn't know it - not for anyone else) or I am deluding myself, but it seems to work so far.