How cold? If the humidity was high in there, then the bass may have soaked up moisture causing the top to swell and also making it less resonant.
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Double Bass How does humidity affect string height/tension?
- Thread starter Chris Fitzgerald
- Start date
Chris, I have a Shen SB180 hybrid, and a large console humidifier set to the apartment never falls below 40%.
I totally agree the dryer the instrument is (such as by the end of the winter heating season) the better it sound - and the more I have to raise the bridge to maintain my preferred string height.
By the end of the summer season the bass is as saturated as it will get with moisture, and it sounds dead and unresponsive - and I will have to have lower the bridge quite a bit to maintain my preferred string height.
But there are marked variations day to day or week to week. Since I tune up each day with a digital tuner. I can see the effect of rainy or humid weather moving in day by day. As the humidity rises, my bass will be a bit sharper each day - if I don't practice for a few days (rarely happens) during a period of rising humidity - I will find the bass a quarter tone sharp when I finally do tune up.
Obviously when the bass is absorbing moisture and expanding I think it is the carved top plate, expanding across the grain that causes the arching to become more pronounced, pushing up the bridge - this coupled with the bridge itself exanding - pushes the strings upward thereby increasing their tension and making the tuning sharp and the bass feel tight.
When you retune to a constant external reference (A 440 or whatever) you then reduce the tension of the strings. So the bass shouldn't feel tight anymore.
I totally agree the dryer the instrument is (such as by the end of the winter heating season) the better it sound - and the more I have to raise the bridge to maintain my preferred string height.
By the end of the summer season the bass is as saturated as it will get with moisture, and it sounds dead and unresponsive - and I will have to have lower the bridge quite a bit to maintain my preferred string height.
But there are marked variations day to day or week to week. Since I tune up each day with a digital tuner. I can see the effect of rainy or humid weather moving in day by day. As the humidity rises, my bass will be a bit sharper each day - if I don't practice for a few days (rarely happens) during a period of rising humidity - I will find the bass a quarter tone sharp when I finally do tune up.
Obviously when the bass is absorbing moisture and expanding I think it is the carved top plate, expanding across the grain that causes the arching to become more pronounced, pushing up the bridge - this coupled with the bridge itself exanding - pushes the strings upward thereby increasing their tension and making the tuning sharp and the bass feel tight.
When you retune to a constant external reference (A 440 or whatever) you then reduce the tension of the strings. So the bass shouldn't feel tight anymore.
I am writing from Spain. Mediterranean weather means rainy winters and dry summers. Now, it keeps raining day by day and my bass -as a living creature it is- experiments some changes: The action gets higher and the sound gets muddier.
I know almost nothing about wood, but i guess that the wetness make the soundpost to expand pushing the top outwards, which raises the bridge and therefore the action.
Where I live, humidity changes are so big that I had the ribs of my former bass (a flat back, by the way ) glued once every spring.
The sound gets somehow subdued as well. Knock a dry wood timber and you will hear its tone. Submerge that timber in water and I just won`t vibrate at all for some time. I think my bass feels the same.
But it is also true that these instruments react quite quickly to said humidity changes, in such a way that taking the bass upstairs- where it is much drier- for just one night will make the wood shrink again, but that is something I do not recommend as I had to repair seams constantly.
I just let it go. Basses are sometimes under the weather.
I know almost nothing about wood, but i guess that the wetness make the soundpost to expand pushing the top outwards, which raises the bridge and therefore the action.
Where I live, humidity changes are so big that I had the ribs of my former bass (a flat back, by the way ) glued once every spring.
The sound gets somehow subdued as well. Knock a dry wood timber and you will hear its tone. Submerge that timber in water and I just won`t vibrate at all for some time. I think my bass feels the same.
But it is also true that these instruments react quite quickly to said humidity changes, in such a way that taking the bass upstairs- where it is much drier- for just one night will make the wood shrink again, but that is something I do not recommend as I had to repair seams constantly.
I just let it go. Basses are sometimes under the weather.
Jake deVilliers
Commercial User
- May 24, 2006
- 6,349
- 607
- Disclosures
- Owner of The Bass Spa, String Repairman at Long & McQuade Vancouver
The grain orientation of the neck, which is an 8" wide piece of wood, is such that it will expand/contract with changes in humidity altering the string height - higher humidity/higher strings etc. I am not sure what effect humidity has on the top/back plates. Theoretically they will expand, the rib structure will allow this movement to occur. On a hybrid w/a ply back there may be more rigidity which means the top plate may buckle slightly upward. I'm speculating
Jake deVilliers
Commercial User
- May 24, 2006
- 6,349
- 607
- Disclosures
- Owner of The Bass Spa, String Repairman at Long & McQuade Vancouver
The spruce top gets quite a lot wider with additional humidity. The ribs do their best to restrain the top, so it arches upwards to relieve the pressure.
You can see this really dramatically on flat top guitars. The top on my D-18 goes concave at 18% RH and the strings almost touch the frets. Spritz a little moisture in the soundhole, close it in the case and half an hour later its playable again...
You can see this really dramatically on flat top guitars. The top on my D-18 goes concave at 18% RH and the strings almost touch the frets. Spritz a little moisture in the soundhole, close it in the case and half an hour later its playable again...
We just got off 3 weeks of heavy rain here in Memphis and I swear my action on my NS La Scala hybrid, at the lowest position on the adjusters, raised a solid centimeter. It was silly - my left forearm was starting to have some tendinitis pains and I was re-evaluating bass as my “power-axe”. It’s back to normal now, thank goodness, but dang (!) that was a pain! It legit got me wondering if I should cut a “high humidity” bridge.
I can definitely feel the difference when we hit dry season here in WNY (which is upon us). The trigger for me to plug in the humidifier is when I go to practice, and the string height feels notably lower to my right hand.
The inverse holds true in the high humidity summer months here, but I feel like playing gut in the heat negates any worries with increased string tension/height. They get looser the more you bang on them to a point, especially if your outside in the heat.
I used to adjust my bridge to compensate, but now I can't be bothered. Keep my practice room humidity up during winter and I just adjust my playing.
The inverse holds true in the high humidity summer months here, but I feel like playing gut in the heat negates any worries with increased string tension/height. They get looser the more you bang on them to a point, especially if your outside in the heat.
I used to adjust my bridge to compensate, but now I can't be bothered. Keep my practice room humidity up during winter and I just adjust my playing.
My understanding is winter and summer bridges and sound posts are not uncommon in some circles.
Humidity is one thing I don't have to worry about with the Alcoa. But temperature expansion and contraction of the DB and of the strings are both very noticeable. In variable weather tuning between songs can become a constant.
I also have an original aluminum body squareneck Dobro built by hand by Rudy Dopyera in his Mosrite workshop in the late 1960s; all of its paint has chipped off, so its body is completely naked aluminum. In the outdoor summer sun it gets too hot to touch, much less try to play; I have to either play it in the shade or I don't play it until night time. I've been really glad my Alcoa is powder coated, as it doesn't get too hot to touch like that in the summer sun.
Humidity is one thing I don't have to worry about with the Alcoa. But temperature expansion and contraction of the DB and of the strings are both very noticeable. In variable weather tuning between songs can become a constant.
I also have an original aluminum body squareneck Dobro built by hand by Rudy Dopyera in his Mosrite workshop in the late 1960s; all of its paint has chipped off, so its body is completely naked aluminum. In the outdoor summer sun it gets too hot to touch, much less try to play; I have to either play it in the shade or I don't play it until night time. I've been really glad my Alcoa is powder coated, as it doesn't get too hot to touch like that in the summer sun.
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I'm on the West Coast (on the beach, actually), and the humidity is stable enough to not need to humidify or deal with different soundposts. My bass sounds horrendous every time it rains. I have a Juzek that has a patch on the top where the finish has worn through near the left side of the fingerboard, and I always wonder if not having a stable barrier to the raw wood affects it more?
