Ukulele Nuisance Noise
Keeping your Ukulele Practice Quiet
By Mango Chutney
We all know that musical instrument practice can annoy other people so how do we keep it quiet.
My son wanted to practice guitar in a tin shed/garage in suburbia and he asked me for advice which was put into practice and he did not get any complaints.
One day tho, a new neighbour stuck his head in and did not say much but was amazed at the low level of noise outside, he heard it but it was too quiet so he investigated.
Our new neighbour was in fact the professor of stringed instruments at the Con and played harp and owned some expensive harps. As it turned out our new neighbour knew nothing of substance when it came to controlling musical nuisance noise.
He had a garage sized wooden structure built in his yard with a high pitched roof and we called it the Harp House. When he was practising for an overseas engagement he did it when I was asleep but before he left to catch a plane. The tonality was amazing and I used to wake up thinking I was in heaven with the harps playing.
Yes he spent a lot of money to control his harp noise but he failed. And yes he is an expert musician of the highest standard and probably one of the best known harpists in the world. (I can’t remember his name, I would have to ask my wife)
So what do we have to know about nuisance noise so that we know enough to control it.
Let there be LIGHT
If we swap noise for light it is easier to understand
Noise is an energy and so is light, they are the same thing but different frequencies, there are similarities with heat and temperature too. A match has a high temperature but will not heat a room but all these things are ENERGIES.
For light we have mirrors that reflect and black surfaces that do not reflect and for noise we have hard surfaces that reflect and soft surfaces that absorb energy and do not reflect it. (bending fibres uses noise energy)
Now the Nitty Gritty
The instrument that measures noise levels (decibels) is a pressure gauge - it measures air pressure changes above normal air pressure caused by the noise source. Our ears do the same thing and our brain converts it to good noise or bad noise with some kind of meaning.
There are two ways of reducing nuisance noise impact,
1. Reflecting noise towards a distant receiver (the light mirror)
2. Using the noise energy by bending fibres. (the light black surface)
Decibels shown as dB (A)
The (A) is a fudge factor used to help the reading be more like our ears perception, We measure the air pressure and add the fudge factor and end up with dB(A).
DB (A) does not add and subtract like normal numbers for example.
1. One machine produces 70 dB(A) in a free field (with no reflectors around it)
2. Add another similar machine and the resultant dB(A) will be about 75
3. Add two more machines and the dB(A) will be about 80
Rule of thumb
Every time you double the amount of noise the dB(A) only goes up by about 5 dB(A).
But that works in reverse too,
If you use up half the noise energy by bending fibres then you only drop the dB(A) by about 5 dB(A),
Sound boxes on stringed instruments
The only energy that is available is the energy emanating from vibration of the strings.
All the sound box can do is collect the noise that did not go forward towards the audience and redirect it to the audience via the hole.
If the sound box did this perfectly for the audience it would be the summation of 2 equal noise sources, one from the strings and one from the hole.
And as we already know that two equal noise sources equals the noise from 1 plus 5dB(A). Say the strings produce 60 dB(A) and the Hole produces another 60dB(A) the resultant noise towards the audience is 65dB(A).
In the non perfect noise box situation, the hole will produce less noise and therefore it will be maybe 3dB(A) louder than no noise box. But that noise level is on the audience side not the musicians side. The noise that would have gone back towards the musician has been redirected forward to the audience via the noise box hole.
Putting a sock in it.
If we put a sock in the hole it will mean very little noise change to the musician and about 2 or 3 d(BA) less for the audience.
Will 2 or 3 dB(A) make a difference,
We have learned to hear the difference between background noise level and the noise source, not the whole noise. So we speak at 5 -8 dB(A) above background, but machines make the same noise level and do not consider the background.
Losing noise with distance
Roughly, if we double the distance the noise level reduces by 5dB(A)
So it works out fine to have a noise box it reduces the noise for the musician who is very close to the noise source and increases it for the audience. So 60 dB(A) at 3 metres is 55 dB(A) at 6 metres and 50dB(A) at 12 metres.
The noise box
Using light the explanation goes like this.
The strings are a fluorescent light tube and the front face of the instrument is a one way mirror that lets light into the box. The light reflects around inside until it finds the hole and then shines out through the hole.
Negative noise
Negative noise is used in car mufflers etc which is of course similar to but opposite to a noise box. Reflected air pressure (noise) in the box can meet itself going the other way thereby neutralizing itself. But if we want pure sound we do not want time delays when it comes out the hole and joins the noise direct from the strings.
My guess is that the front face is a one way mirror and the back is the main reflector and the shape of the sides is to make negative noise for more pure sound. (less stray out of synch noise)
Noise power
Gets more complicated but if a uke was a match then a double base would be a gas ring.
Ideal Practice room
The ideal practice room has free hanging fabric walls and no openings and the fibres are bent so the noise energy does not leave the room, It makes no noise level difference to the musician.
Household background noise levels usually are 45 to 55 DB(A) and anything that is 5dB(A) above background becomes intrusive.
Have fun.
The end
© 2014 C.J.Griffin
PS If you take a few readings with a cheap noise level meter you can work out what is reasonable.
Keeping your Ukulele Practice Quiet
By Mango Chutney
We all know that musical instrument practice can annoy other people so how do we keep it quiet.
My son wanted to practice guitar in a tin shed/garage in suburbia and he asked me for advice which was put into practice and he did not get any complaints.
One day tho, a new neighbour stuck his head in and did not say much but was amazed at the low level of noise outside, he heard it but it was too quiet so he investigated.
Our new neighbour was in fact the professor of stringed instruments at the Con and played harp and owned some expensive harps. As it turned out our new neighbour knew nothing of substance when it came to controlling musical nuisance noise.
He had a garage sized wooden structure built in his yard with a high pitched roof and we called it the Harp House. When he was practising for an overseas engagement he did it when I was asleep but before he left to catch a plane. The tonality was amazing and I used to wake up thinking I was in heaven with the harps playing.
Yes he spent a lot of money to control his harp noise but he failed. And yes he is an expert musician of the highest standard and probably one of the best known harpists in the world. (I can’t remember his name, I would have to ask my wife)
So what do we have to know about nuisance noise so that we know enough to control it.
Let there be LIGHT
If we swap noise for light it is easier to understand
Noise is an energy and so is light, they are the same thing but different frequencies, there are similarities with heat and temperature too. A match has a high temperature but will not heat a room but all these things are ENERGIES.
For light we have mirrors that reflect and black surfaces that do not reflect and for noise we have hard surfaces that reflect and soft surfaces that absorb energy and do not reflect it. (bending fibres uses noise energy)
Now the Nitty Gritty
The instrument that measures noise levels (decibels) is a pressure gauge - it measures air pressure changes above normal air pressure caused by the noise source. Our ears do the same thing and our brain converts it to good noise or bad noise with some kind of meaning.
There are two ways of reducing nuisance noise impact,
1. Reflecting noise towards a distant receiver (the light mirror)
2. Using the noise energy by bending fibres. (the light black surface)
Decibels shown as dB (A)
The (A) is a fudge factor used to help the reading be more like our ears perception, We measure the air pressure and add the fudge factor and end up with dB(A).
DB (A) does not add and subtract like normal numbers for example.
1. One machine produces 70 dB(A) in a free field (with no reflectors around it)
2. Add another similar machine and the resultant dB(A) will be about 75
3. Add two more machines and the dB(A) will be about 80
Rule of thumb
Every time you double the amount of noise the dB(A) only goes up by about 5 dB(A).
But that works in reverse too,
If you use up half the noise energy by bending fibres then you only drop the dB(A) by about 5 dB(A),
Sound boxes on stringed instruments
The only energy that is available is the energy emanating from vibration of the strings.
All the sound box can do is collect the noise that did not go forward towards the audience and redirect it to the audience via the hole.
If the sound box did this perfectly for the audience it would be the summation of 2 equal noise sources, one from the strings and one from the hole.
And as we already know that two equal noise sources equals the noise from 1 plus 5dB(A). Say the strings produce 60 dB(A) and the Hole produces another 60dB(A) the resultant noise towards the audience is 65dB(A).
In the non perfect noise box situation, the hole will produce less noise and therefore it will be maybe 3dB(A) louder than no noise box. But that noise level is on the audience side not the musicians side. The noise that would have gone back towards the musician has been redirected forward to the audience via the noise box hole.
Putting a sock in it.
If we put a sock in the hole it will mean very little noise change to the musician and about 2 or 3 d(BA) less for the audience.
Will 2 or 3 dB(A) make a difference,
We have learned to hear the difference between background noise level and the noise source, not the whole noise. So we speak at 5 -8 dB(A) above background, but machines make the same noise level and do not consider the background.
Losing noise with distance
Roughly, if we double the distance the noise level reduces by 5dB(A)
So it works out fine to have a noise box it reduces the noise for the musician who is very close to the noise source and increases it for the audience. So 60 dB(A) at 3 metres is 55 dB(A) at 6 metres and 50dB(A) at 12 metres.
The noise box
Using light the explanation goes like this.
The strings are a fluorescent light tube and the front face of the instrument is a one way mirror that lets light into the box. The light reflects around inside until it finds the hole and then shines out through the hole.
Negative noise
Negative noise is used in car mufflers etc which is of course similar to but opposite to a noise box. Reflected air pressure (noise) in the box can meet itself going the other way thereby neutralizing itself. But if we want pure sound we do not want time delays when it comes out the hole and joins the noise direct from the strings.
My guess is that the front face is a one way mirror and the back is the main reflector and the shape of the sides is to make negative noise for more pure sound. (less stray out of synch noise)
Noise power
Gets more complicated but if a uke was a match then a double base would be a gas ring.
Ideal Practice room
The ideal practice room has free hanging fabric walls and no openings and the fibres are bent so the noise energy does not leave the room, It makes no noise level difference to the musician.
Household background noise levels usually are 45 to 55 DB(A) and anything that is 5dB(A) above background becomes intrusive.
Have fun.
The end
© 2014 C.J.Griffin
PS If you take a few readings with a cheap noise level meter you can work out what is reasonable.
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