Hi everyone. I just finished my first guitar. I wanted to use stuff I just had lying around, so instead of a cigar box, I used a wood box from a gun cleaning kit. Its dimensions are similar to a cigar box, and it's thin wood as well (not sure what kind)--as thin or thinner than most cigar boxes. I wired up a volume pot and put a piezo inside (tried putting it both on the underside of the lid and on the bottom of the box) and it just doesn't get much sound. I have a little 15 watt practice amp, and to get any volume out of it, I get to the feedback stage, and the piezo picks up ever little touch/scrape of the box much more than it picks up the guitar sound. The lid doesn't fit perfectly all the way around--the edges are warped in a couple of spots so there are some gaps when it's closed (the top is not warped though). Would this cause the problem, or is the wood just not resonating enough?
Thanks,
zombieCat
Replies
Hi.
There are two ways of putting a piezo in the bridge (well, at least two). You can simply embed one or more disk piezos between two pieces of wood and then put a metal rod on the top. Michael has a photo of the ones he does here. I did something similar with a metal bridge plate where I fixed the piezos to the metal plate and put very thin wood on the back, between the metal plate/piezos and the box. There are stage by stage photos accessible through my page. Skeesix puts cork between the wood and the box to insulate more from body knocks. I will try that.
The piezos can either be wired in series or parallel. I wired mine in parallel because they are supposed to sound a bit more mellow and also if one fails it won't stop the other/s working.
The other option that I have tried is to use a rod type piezo. I used it on my first one. I made an ebony bridge with quite a deep slot and a hole going through to the box lid for the cable. The rod sits at the bottom of the slot and a brass rod sits on top. This benefits from decent pressure to get the piezo working well. At first it wasn't very loud but then for other reasons I raised the bridge and the volume increased noticeably. Mine came with only a passive amp, with now power source. You can get them with little battery powered preamps which are probably better, although the preamp is a big of a lump.
My feeling is that the disk piezos are less dependant on bridge pressure and are more sensitive. They don't seem to need any preamp so that is probably the direction I would go in the future. On my third (latest) instrument I combined two piezos in the bridge with a magnetic pickup (rail humbucker) and use two volume controls to balance the two to achieve the tone I want. All I can say is that I am very happy with this arrangement.
Good luck. Keep us informed.
I would like to know how you get on with the copper reso cone. Copper is one of the most resonant metals so I think it might be ideal. If you are spinning your own my guess is that it would need to be kept well lubricated to avoid grabbing, but shouldn't be worse in that respect than aluminium. I look forward to seeing what you do with that.
All the best.
John
John, thanks for the link to the fret calculator, that will come in handy.
Michael, thanks for the info. I now have the bridge within about a couple inches of the tail piece, and I used a solid hardwood dowel sanded flat on the bottom as a bridge. It's pretty high--the strings are a good half inch off the body/neck. I'm getting a bit better sound, but not appreciable. I'm thinking I may be running into a bad box now. I have a quick question--looking through your pics (which are fantastic, by the way), I see you mention a piezo bridge. Are you embedding a piezo in the bridge, underneath the rod? I did a forum search for piezo bridge and waded through a few pages but didn't find any good info.
And I'm having a lot of fun with this. I have all sorts of ideas coming up now, including trying to figure out how to make a copper resonator cone :)
Thanks.
There are lots of places to get the scale length dimensions. If you go under the forums menu at the top and then put a search in for scale length. I have used the free online calculator from the http://www.stewmac.com/ site. You set the length and number of frets (doesn't hurt to put in more than you need) and the units. Probably best to do it in millimetres because it is easier to measure out accurately.
All the best.
Thanks John. I have a few things in mind, I'm going to experiment. On the question of scale length, I'm sure I'll end up with a non-standard one. Is there a formula for fretboard layout, or do people generally just grab a tuner, find the note and mark it? I suppose a forum search would yield an answer.
As for learning, I figured I'd jump right in so I'd know what questions to ask :)
Off to search the forum.
Hi. Depends on the design of the tailpiece of course, but in most cases that won't help because the line from where the tailpiece in fixed to the bridge remains the same and so the break angle also remains the same. The objective is to change the string angle, not to move the string ends nearer the bridge. I have seen people fix a bar across the strings part way between the bridge and the tail, fixed to the box, in order to bring the strings down. I suppose you could think of it as doing the same thing as a string tree, only at the other end. Of course you might not like the look (I don't think I would be keen), in which case through body stringing is probably going to be the best way to go.
A fretboard would allow you to raise the bridge and, as you say, change the scale length in order to move the bridge. Both of those things sound like a good idea.
If the strings are high now they may not seem so high when you have a fretboard. Just as a test to see if all this is likely to help, why not make a really high bridge (really stupidly high). I know it will be hard to play but it will tell you if this is what is causing the problem. Better to do this now rather than find that it wasn't the cause after you have been to a lot of trouble.
Your comment about not taking things into consideration. That's just called learning. Many of us are still doing lots of that. Just check the forums ;-)
Thanks for all the replies everyone. This was a quick and dirty job, so now I see where I would do things differently. I'll try to either find a different tail piece that moves things closer to the bridge or try to do a through-the-body string setup. I may also try to throw a fretboard on it, primarily so I can move the bridge further back and make new fret markers. Its current position is due to the fact that I marked the frets from another guitar before putting everything together. That, and I didn't take into account the full length of the scale before starting.
I have cut the bolt down to size and it doesn't make much difference. I also need to use a bridge and nut that aren't so tall. Right now, the strings are extraordinarily high.
Thanks again for all the responses. Having just jumped into this, there are many things I didn't take into consideration before starting. That's one reason I just used stuff I had lying around--not a lot of time or money spent on screwing things up while figuring this stuff out :)
Maybe cut the bolt so it is shorter, as in a little bigger than the width of the strings. it might be sucking up some sound
You could add a fret board and this would give you more room for a higher bridge, and you could even flatten the bolt on the bottom so it contacts the wood better. SA fret board would allow you to move the bridge back on the body or to try and find the optimal spot.
I don't know if anyone picked up on this, but one thing I noticed and can relate to is the distance between your tail piece and the bridge. I've done one build like that and compared to my other builds seems to lack in volume. But who I built it for loves and cherishes it so it' all good. Keep at it man, you'll get it!!
Ah yes, I see now that John and Dan are on the same page, what they said Zombiecat....
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