Tone Quality Reduction?

[John]

Recently, I have experimented with lowering the action on my mandolin. #I have the action pretty low at the moment and am enjoying the ease with which the instrument plays. #However, I think the quality of the tone has somewhat changed. #I've read (and believe it to be true), that the volume may decrease when the strings are lowered, but I've not come across discussion on the sound quality perhaps changing after lowering the strings.

Do any of you have experience with this or am I imagining it?

Thanks.

[Bob DeVellis]

It could well be. Heavier strings may give you more of the old-setup tone with the lower string height. You'll come closer to the old tension but through girth rather than height. I think each mando has a tonally optimal range for its string tension -- the right amount to drive that particular instrument. Go higher or lower and tone can suffer. Height has a substantial effect on tension, but so does gauge. The question then becomes whether you prefer the feel of lighter gauge strings set higher or heavier gauge strings set lower. Many instruments optimized for bluegrass really seem to sound best with pretty heavy strings and pretty high action. My preference is for lighter-built instruments that are intended for less tension, but that's personal and subjective. Also, as your hands get stronger from playing, what used to seem like high action may feel less so. But I still prefer nice, low action.

[arbarnhart]

This has been beat to death in the builder's forum a few times and between the folks who should know best, there is no clear concensus. Here's an eye opening observation for you - on a mandolin with small frets, it is impossible for the break angle over the fret to be more than a few degrees and the corresponding string pressure on the fret itslef cannot be much either (now matter how hard you mash it into the finger board). Yet there is this perception that unless the strings take a deep dive over the bridge tat it won't work right. I did a poor job setting the neck on a flat top I built and to get decent action I had to go to an insanely small break angle. #There may be a slight difference in tone, but I don't notice any.

[John Flynn]

I read an interview with Jethro Burns where he disputed the "lower action, better tone" idea. I read another interview with Norman Blake where he said he likes his actions "dangerously low." I have also read that Chris Thile likes a very low action. I have tried raising the action on two of my mandos and haven't been impressed with any tone improvement. What I have seen is that my adjustable bridges will tend to "bend forward" slightly when they get too high, which can't be good.

[mandogrrl]

Richard Starkey from Martin recently set up my mandolin and raised the action. I thought it sounded much louder. A little bit harder to play though. I'm getting used to it.
http://www.mandolincafe.net/iB_html/non-cgi/emoticons/mandosmiley.gif

[Bob DeVellis]

Let me restate my earlier point in light of others' observations. I think an instrument can be optimized for low, medium, or high action. If it's built like a tank, a low action isn't likely to generate enough downforce to effectively activate the top. On the other hand, if it's lightly built, too much downforce may dampen the top. So, I don't think it's a question of there being a consistent "right height" for all mandolins, but a range of more effective bridge heights for a particular mandolin. It sounds to me like Abarnhart's mandolin was a real success by my standards, one whose costruction didn't compromise tone when the action was nice and low.

Another point that Abarnhart's post emphasizes is that neck angle is important. If the neck angle is steep, you can have a really high bridge but a very low action. The strings are high off the top but the neck is right there, just under them. the same bridge height and string angle would give horrendous action on an instrument with a less steeply set neck. My subjective impression is that, even on instruments originally set up with a pretty high bridge angle, lowering the bridge doesn't necessarily compromise tone or volume. Tone may change, but I wouldn't necessarily say that the change is for the worse. I have a Weber, for example, that improved in tone to my ear when the action was lowered. Tone and volume are sort of a balancing act among multiple variables. The state of any one variable isn't very informative unless you take the others into consideration. Neck angle, string gauge, bridge height, top thickness, bracing, top material, nut material, and others all play some role.

[John]

Good replies folks and I appreciate them. #Bob - I especially like your observations and they make good sense. #I hadn't considered the idea that I was decreasing the tension of the strings by lowering the string height. #Perhaps, I should have added to my original post that I use light gauge strings (J62's). #I have been steadily lowering my bridge height over the course of a few weeks - 1/3 turn or so at a time. #My thinking, was that as long as I didn't hear any buzz, everything was cool. #

This morning I started raising it back up a bit - perhaps a 1/2 turn or so total and to my ears the tone has improved. #At least I think it has...

[arbarnhart]

You don't increase or decrease string tension; it still must be the same for a given diameter metal strand to produce the specific note at the scale length. You might change it temprarily while adjusting, but getting in tune will get it the same (or extremely near the same). What you increase or decrease is the downward pressure on the bridge - how hard it presses on the top. The concern is that if there isn't enough pressure, the vibrations won't transfer to the top. The reality is there really isn't anywhere else for them to go. Obviously if it was so loose that it moved around and buzzed that would be a problem. But with 8 strings all applying pressure, just the tiniest break angle holds a well fitted bridge in place just fine. However, the amount of pressure on a top can affect how well it trasnmits those vibrations .