Bridge position and impact on tone and volume?

[Douglas McMullin]

The intonation on my Phoenix Standard had been working its way out of shape for a little while, and I had attributed that to humidity changes over the summer months. My tone and volume were still great to my ear, and since it was not out all that much I had left it be for while. Last night I decided to make a quick adjustment, which required moving the bridge aft 1/16" or so, and something interesting happened. Volume and tone each had a very substantial change for the better. At first I thought it must be wishful thinking or my imagination, but the change felt like quite a shift. My wife even yelled down shortly after I started playing post adjustment and asked why I was playing so hard. Then I got the bright idea to pull out my digital recorder that I had been using, and sure enough, with same position/distance and settings I was now maxing out the recording levels frequently when I was well below them an hour before. Unfortunately I did not save any of the earlier recording attempts, so I can't A/B the audio.

I know this must sound a little implausible, but I swear that this bridge adjustment has had a huge impact. I came home tonight, grabbed the mando, and every bit of it was still there.

So the question is what has happened? Did I get the bridge back on some sweet spot over the top or bracing? I am pretty sure that the bridge had the same contact with the top before and after the move, so it does not appear to be a leaning bridge type fix. I am not complaining as the increased volume and bark keep causing my jaw to drop, but I would love an explanation that will support the notion that I am not dreaming.

[Rob Gerety]

My bet - leaning bridge syndrome! It doesn't take much.

[F-2 Dave]

1/16th can make a lot of difference. A while back, I hadn't played my F2 for months, I got it out and played, but it wasn't quite right. I kept messing around with it and finally moved the bridge just a very little bit. Bam. Everything fell into place and it was like a different mandolin.

[Douglas McMullin]

My bet - leaning bridge syndrome! It doesn't take much.

I would think that as well, but I have the bridge a good inspection before I moved it, and it looked well seated on the top. I guess it could still have been up to some degree not readily detectable by the eye.

[Douglas McMullin]

1/16th can make a lot of difference. A while back, I hadn't played my F2 for months, I got it out and played, but it wasn't quite right. I kept messing around with it and finally moved the bridge just a very little bit. Bam. Everything fell into place and it was like a different mandolin.

That is pretty much what I am experiencing; this suddenly felt/sounded like a different instrument. The bark on the D strings is vibrating a filling in one of my molars, and I am quite certain that has never happened before. :)

[Hal Loflin]

Hey Doug...Have you rechecked the intonation at the 12th fret to see how close it is to dead on? I had a similar experience with my Weber Yellowstone and found that the adjustment was part due to the intonation being very close to perfect at the 12th. Which I figured was due to the bridge being perfectly (or close to it) positioned.

[Douglas McMullin]

Hal, it is as close as I can get it. I am using both my ear and my Turbotuner stobe tuner to verify it, and it is not dead on perfect, but I don't think I can move the bridge in small enough increments to improve it beyond where it is now.

[Hal Loflin]

What I had to do to get it almost perfect was have the treble side just a tad closer than the bass side. By tad I mean barely noticeable. I used the old tune the E and G pairs to full pitch, with the A and D pairs slack, until the intonation was on. Then when I tuned the slack pairs up to pitch they were almost perfect. I know it is almost impossible to get all dead on but boy I sure got as close as I ever have and the tone and volume was just like what you are experiencing.

What I learned, and I suspect what you are experiencing, is that when the bridge is perfectly positioned the instrument will perform best.

[Ivan Kelsall]

As long as the bridge is correctly positioned,the intonation should be close to spot on - it never will be 100%, because the frets are only in a very,very close approximation to the ideal position. After that, the bridge needs to be set at a reasonable height to produce a good volume as well as keeping the action comfortably low. Too low an action can result in a loss of volume & a lack of clarity in the intonation. Rob's remark re.a leaning bridge is also spot on,it only takes a degree or so of 'leaning' to bring the action down & to affect the intonation.
I had an enlightening experience several months ago.I took my Weber Fern to my local luthier to have the truss rod adjusted in order to lower the action very slightly,to bring it to the same height as my Lebeda Mandolin. There was at most,a half turn to be had on the truss rod. However,there was an immediate improvement in the intonation on the E strings, especially above the 12th fret (i do play there),but after a couple of days settling down,the volume increased dramatically. I still can't get my head around why such a tiny movement brought the huge changes about,but they did,
Ivan

[Tim2723]

My guess is that Rob nailed it with leaning bridge syndrome. In terms of breaking contact with the soundboard and reducing volume, you may not be able to see it, since it takes only the tiniest fraction of an inch to break the contact. Missing by 0.0001 inches is still a miss.

I wonder just how far a fret can stray from its ideal location before the change in pitch is noticable? I imagine that the tolerance would be pretty small for a mandolin.

[Bertram Henze]

My guess is that Rob nailed it with leaning bridge syndrome. You may not be able to see it, since it takes only the tiniest fraction of an inch to break the contact. Missing by 0.0001 inches is still a miss.

This is my guess as well. You might not even be able to slide a hair under the bridge while it's still tilted enough to make bad contact. It's a very microscopic phenomenon.

[Douglas McMullin]

Bridge lean could have been part of the equation or the whole reason, but again I have to say I suddenly entered territory that I don't think this mandolin has been to during my first 16 months of playing. It sounded really good before; it is blowing me away now. I have made a number of small bridge adjustments in the past and had never stumbled upon this magic spot. I guess now that I know the full potential of this instrument, I need to very aware of changes, and not be hesitant to make adjustments when the sound is not meeting my new expectations.

[Brent Hutto]

Reading this thread just sent me off to look at my mandolin real closely. What I'm reading here seems to say if I can force a piece of paper maybe 1mm-2mm under the back corners of the bridge (both the treble and bass side corners) that's a very bad thing, right?

We've had a noticable change in household humidity the past few days. My guitar sounds stuffed up a bit and the little Redline Traveler seems to be a bit flabby sounding on the G and D strings. I attributed it to 55% instead of 45% humidity but I wonder if the change in humidity could have made my bridge rock forward a mite. I could have sworn those corners were quite flush with the soundboard a week ago...

Is it just a matter of slacking the tension off the strings a little and tweaking it until the paper won't go under those corners?

[Big Joe]

If you want to check bridge for forward lean just grab the saddle firmly at both sides and pull back firmly but only on the saddle. Don't slide the bridge bass. It will either move or it won't. Don't knock the bridge over. It may make a nasty little ding in the top. Humidity changes can affect instruments substantially at times and can cause them to sound different from day to day. This is especially noticeable on banjos with skin heads. They can loosen and tighten quite a bit with changes in humidity. The same applies to wood, but it does not move as much as the skin on a banjo head does.

Most likely the original posters bridge was slighty forward of where it should have been for best intonation. That shortens the scale slightly and does not allow it to play in tune with itself. Once the bridge is back where it belongs the difference can be amazing. Scale length is restored and it will play much better in tune with itself...as much as a tempered instrument will anyway. We see a lot of mandolins come through with the bridge saddles leaning forward and a lot with the bridge out of place.

This movement can happen a lot of ways but I think it most often happens over time as you change strings. When you change them you reduce tension and reapplly tension and it can move slightly in the process if you are not very careful. This is often when the saddle begins to lean forward. As you re apply the tension the strings pull from the top and can make the saddle lean a bit or the entire bridge. If you check two things after changing strings it can save you a lot of frustration. First, just make a visual look. If the bridge appears to lean at all towards the fingerboard, straighten it up. Second, if there is a gap at the bridge bass where it hits the top on the back side, then lean the bridge back if you can. The other thing to do is to check the note in tune open and then again at the 12th fret. If it sound right go on. If not, make the adjustment if you can.

[jim_n_virginia]

Is it just a matter of slacking the tension off the strings a little and tweaking it until the paper won't go under those corners?

Your bridge is probably leaning too. Straighten it up and if you can still slide wood under the feet it the bridge may need to be refitted. But it probably doesn't if it is a Redline.

[Brent Hutto]

yep, piece of cake. I just tuned everything down a whole step and gave it a good bit of finger pressure on both top corners. All is flat and snug now.

[Tim2723]

I've noticed that this sort of problem is more common among those who work to avoid having to adjust their bridge, such as taping it down when changing strings. This is just a good example of why we should not fear making these adjustments. They're easy to do and just part of owning a mandolin.

[Douglas McMullin]

I've noticed that this sort of problem is more common among those who work to avoid having to adjust their bridge, such as taping it down when changing strings. This is just a good example of why we should not fear making these adjustments. They're easy to do and just part of owning a mandolin.

I don't mind making bridge adjustments myself. I just hadn't gotten round to doing this once since the summer humidity caused its changes. Like I said though, past adjustments never got anywhere close to these results.