Bridge size and sound quality (duh huh moment)

So, I don't usually make large bridges as you can see below. I make them so that they don't interfere with the other design elements or overpower the lid. However on a later build of mine, I did make one larger than shown. Under the one below I have two piezos in parallel glued on the lid. On the one with the larger bridge, I only have one.

Before I added the larger bridge (Hall of Shame moment), the volume was ok. Now, it's much greater! Hmmmmmm. So I wonder from those with experience in such, am I seeing that a larger bridge allow for greater sound transfer and thus greater volume or tone? I believe the conclusion is Yes!

Anyone want to confirm this? I'm planning on using my newer design in the future.

Thanks

-WY

Replies

Mungo Park May 17, 2010 at 12:39am

The placement of the bridge on the box will change the sound and volume as well, try moving it a little closer into the center of the box and see what happens, as well as mentioned a flat fit of the bridge will transfer the sound better. It seems a skinny top where the strings touch is better as well.
The banjo bridge maker talk a lot about the grain orientation in the bridge. Basically quatersawn pieces are used.
Cheers Ron.
Chester Winowiecki May 16, 2010 at 2:40pm

Thanks for that link, Mark! A very cool site with great info and very DIY friendly. Looks like there's a lot there, too. I'm just getting into it, but I already a have an idea for drilling some holes into the bridge of the CBG that I just finished yesterday.

Mark Werner said:
I used a "Red Henry" style bridge on my mandola and a couple of other instruments:

http://www.murphymethod.com/redbridge.html

The light, hard material seems to transfer energy well. A higher bridge does use more string pressure, but also requires that the neck be angled appropriately if you want a decent action.
I think a balancing act between bridge and top must go on...Lots of room for experimentation.
Wade May 16, 2010 at 10:33am

Another point to consider about volume and if you compare your builds is the quality fit of the bridge to the vibrating surface. I final sand the bridge on the instrumant to make sure there is good contact.
Outhouse Instruments May 16, 2010 at 6:58am

Having the disc between the bridge and lid takes the box pretty mucj completely out of the pic. This is what I do with D-bows. Nice , nasty, growly sound. Lots of vibe going straight into the disc.
I would suggest doing both to the same cbg and comparing the 2.
I have noticed that in the box .... there is very little diffefence where you put the disc in volume, but place does make a difference in how it sounds .. hi's, low's, bassy, trebbly, etc.

Matt
Bob Harrison May 16, 2010 at 12:21am

I can't add to this,I don't know. But I like your bridge,it's a nice looking design and your photos are very good:)
Cheers
Bob
Mark Werner May 15, 2010 at 10:47pm

I used a "Red Henry" style bridge on my mandola and a couple of other instruments:

http://www.murphymethod.com/redbridge.html

The light, hard material seems to transfer energy well. A higher bridge does use more string pressure, but also requires that the neck be angled appropriately if you want a decent action.
I think a balancing act between bridge and top must go on...Lots of room for experimentation.
MichaelS Country Boy Guitars May 15, 2010 at 12:04am

My bridges are open in the middle like a banjo or violin type. I found that a wider set feet seemed to sound better on one that I changed the bridge on. The height was kept the same, and the feet are about the same size, just spaced further apart. This is an all acoustic cbg.
Chester Winowiecki May 14, 2010 at 8:44pm

Really great discussion, guys...and good information, too. Here's what I recall reading about bridges: A hard saddle is good because it won't dampen the vibration of the string and allow it so sound clearly. A light bridge is good because it won't absorb the vibrations and can transfer them quickly to the soundboard. A taller bridge means more downward string pressure and more vibrations going to the soundboard. This is all for acoustic instruments, electrics are somewhat different... you want a massive bridge and saddle that won't absorb any vibration and let all of the energy stay in the string where it can get picked up by the "pick-up".
Now I'm not sure where bridge size matters but the only thing I can think of is how loud a banjo is with it's tiny bridge compared to a guitars wide flat bridge. I want to say smaller is better if you can get away with it (that is, if you don't need to make it larger due to the huge pull and pressure of the strings being attached to it.) An archtop bridge is much smaller than a normal acoustics's.
Wes "I'm Baaaaack" Yates May 14, 2010 at 4:53pm

By Jove, I think we're on to something!

-WY
Tracy Kennedy May 14, 2010 at 4:29pm

Is it possible that the larger surface area of the bridge allows the otherwise small string vibrations resonate deeper and futher into the soundboard? Say ...like a childs footprint in the mud leaves a small impression (small bridge), likewise a mans footprint would leave a larger impression (large bridge) . Redneck logic

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