Winter sound posts

[asovcl]

This is probably a juvenile question to which I should already know the answer, but I just don't.  In the winter when the humidity drops, and everything 'shrinks' (including wood...), shouldn't my SP be adjusted looser to compensate?  

 

When I ask friends, they mostly just say "I live with it", but my sound becomes so harsh, and the instrument so unresponsive, I find it hard to live with.

 

Am I reading too much into this?  Do I just need to 'live with it' to avoid the nuthouse?

 

Thx.

 

[David Burgess]

It's common, in climates with a big indoor humidity swing between winter and summer, to move the soundpost inboard during the winter to relieve tension due to the instrument contracting. Winter and summer soundposts have also been used, but that's not so common these days. More people still use a winter and summer bridge.

 

But if you control the humidity year-round (which isn't very hard these days), you won't need to mess with this stuff, and it's also much easier on the instrument than subjecting it to repeated dimensional changes.

[Violadamore]

But if you control the humidity year-round (which isn't very hard these days)

Maybe not hard for you, but relative humidity here over the last 2 days has swung back and forth between 14% and 97% depending on time of day.  Where I am, this is not unusual.  Every time someone opens a door......... 

[asovcl]

David,

 

Thank you.  I think you're exactly right about just trying harder to control humidity instead of driving my luthier nuts.  We had a rather severe cold snap in recent days that drove the humidity down.  I guess I just need to pay closer attention to my humidifier.  I know we discussed humidifiers in detail, I'll do a search.

 

Thanks again.

[David Burgess]

Maybe not hard for you, but relative humidity here over the last 2 days has swung back and forth between 14% and 97% depending on time of day.  Where I am, this is not unusual.  Every time someone opens a door......... 

Oh come on, I'm sure you can do much better than that if you want to.

 

But if you don't, perhaps you still have a 24-hour average that's decent? It takes some time for instruments to gain and lose much moisture.

 

Oh, maybe you're talking about the outdoor humidity from a weather report, because I don't think I could get the indoor humidity to change that much in a day if I tried!

You could get some large swings though if you're using a fireplace for heat. Relative humidity levels could rise during the night when the temperature drops and the air exchange rate goes down, and then all that moist air goes up the chimney during the day when the fire is going.

 

Anyway, we can figure this out if you want to.

[Peter K-G]

I have studied this phenomenon for years. This is not a minor issue. In modern houses where regulated ventilations is installed humidity can go down to almost 0%. Violins can become harsh and almost unplayable, bow slips not gripping the strings and you don't like to play the violin. The worst of all is that one time in this condition a violin may never go back to it's original state due to creap. It is like you heat treating the wood.

And they can crack too.

Finnish study in the matter:

http://www.maestronet.com/forum/index.php?/topic/328430-peter-kgs-bench/?view=findpost&p=612883

[David Burgess]

Peter, right now the temperature where I am is the same as in Helsinki, and the outside air is dryer. My shop is at 40%. If it was 30 degrees colder, my shop would still be at 40%.

 

Are humidifiers illegal in Finland or something? Or is the required air exchange rate so high that they don't make much of a difference?

[Peter K-G]

Humidifiers are installed all the time nowadays. First our houses was regulated some 15 years ago to use expensive ventilation systems to save energy. The study i posted (Finnish language) showed that we haven't saved energy, because when humidity drops we want to turn up the temperature. Increase in astma and other health problems is a side effect. The study shows that in our modern houses humidity can go almost to 0%, 10 % is quite common in Jan - feb. In my workshop I have some control (basement), it is 28 % now.

Nowadays we are installing humidifiers for healthy reasons. The next would be to go back 100 years and make houses that works in our climate, like they use to. Helsinki is 500 km south from where I live

[Peter K-G]

And I have two cracked tops, one from last winter and one the winter before. Another maker had three a couple of years ago.

[David Burgess]

Humidifiers are installed all the time nowadays. First our houses was regulated some 15 years ago to use expensive ventilation systems to save energy.

That's probably what we call an "energy recovery ventilator". They recover some of the heat from the exhaust air, but none of the moisture. If the air exchange rate is high enough, it might be pretty hard to keep the moisture level up.

 

Off the top of my head, I think the minimum for newly constructed commercial occupied buildings here (like a school or office) is around three air exchanges per hour. What is it for homes over there?

[Peter K-G]

One time per two hours, it is almost impossible to keep the humidity level up. Add to that floor heating and 30 cm thick isolated walls, with plastic film all around, as the first layer from the inside.

[David Burgess]

For those who don't know what we're talking about:

 

As they started making homes tighter and tighter for energy efficiency, a new problem developed. Indoor air pollution (including carbon dioxide, off-gassing from building materials etc. And sometimes interior moisture levels could get too high. So they started requiring that certain amounts of stale air be exhausted, with air brought in from the outside to replace it. In a cold climate, this cold air needs to be heated to the inside temperature, which requires more energy. So in some ways, they just went in a big circle.

 

Air exchange rate: This is based on the amount of outside air that would need to be brought in to replace all the air in the house. So if a house is 2000 square feet, and has 8 foot ceilings, achieving an air exchange rate of 1 per hour would require that you exhaust 16 thousand cubic feet of air per hour, and bring in and heat the same amount from the outside. Probably a little healthier, but pretty horrible from an energy conservation standpoint. And like Peter says, it's a pretty ambitious job to humidify 8000 cubic feet of air per hour (his rate is 1 exchange per two hours) when this outside air winds up around 5 percent humidity after it's heated to inside temperature.

 

However, my air exchange rate is about the same, and my shop still never goes below 40%.

[Christopher Jacoby]

Houseplants houseplants houseplants!

[Jerry Pasewicz]

Houseplants houseplants houseplants!

How about an indoor waterfall that leads gently and peacefully into a koi pond? Kumbaya...

[Rue]

...aquariums also work well...not controlled...but they definitely provide humidity...and they look nice...(well, if you look after them that is)...

[David Burgess]

Houseplants houseplants houseplants!

But then I'd need to move into a much bigger house, to have enough room for all the plants it would take. Then it would cost more to heat.

[Jerry Pasewicz]

But then I'd need to move into a much bigger house, to have enough room for all the plants it would take. Then it would cost more to heat.

Or you could work at the gym..

[Rue]

That's the solution!  And think of the manly quality that invasive 'eau du locker room' fragrance would give the instruments!

[Addie]

I usually need to do a couple of post adjustments as winter sets in. Like the OP I can't stand the sound. I also freak out when the RH dips below 40.

[David Burgess]

Or you could work at the gym..

Why didn't I think of that? Or I could just run a long hose between my house and the sauna. Might even be able to yodel through it.

[DarylG]

Hi David, what do you keep your workshop humidity at during the summer?

[Addie]

Why didn't I think of that? Or I could just run a long hose between my house and the sauna. Might even be able to yodel through it.

Nah, workbench next to your Olympic sized indoor pool should be fine. And friends don't let friends yodel.

[David Burgess]

Hi David, what do you keep your workshop humidity at during the summer?

Maximum of 60%.

[David Burgess]

Nah, workbench next to your Olympic sized indoor pool should be fine. And friends don't let friends yodel.

Even when we're wearing cute leather hot-pants? ;) ;)

 

[Addie]

The "hot pants" you posted are not leather, they're fake costume hot pants. But they're probably better suited to the sauna and pool.