Focusing sound waves

  • Thread starter ayushmorx
  • Start date
9
0
Can we focus parallel sound waves using convex and concave lenses since they essentially follow the same laws of refraction as light?
If not, is there any way to focus parallel beams of sound to converge at a point?
 
1,948
200
Yes. Either by reflection (sound mirrors) or by refraction (sound lenses). Note that concave lenses will actually be divergent because sound speeds is higher in solid objects than in air. Convex lenses would be convergent. Also note that Parabolic mirrors will probably work better because a large fraction of the sound is reflected as oposed to being refracted.
 

Drakkith

Staff Emeritus
Science Advisor
2018 Award
20,620
4,352
In Shreveport Louisiana they have the "Sci-Port" science center. One of the displays they have involves to large parabolic dishes about 6 feet in diameter placed about 20 feet apart. If you and a friend stand in front of each dish, you can speak in a normal voice and clearly hear the other person even across the room thanks to the dishes focusing the sound waves.
 
9
0
Hey everyone thanks for your quick response!!!
I basically wanted to converge the sound waves onto a diaphragm, while keeping them in phase so as to maximize efficiency of sound energy transfer to the diaphragm(constructive interference). Will the reflection of the mirrors or reflectors cause any phase change? if so, how can I eliminate it?
 
1,948
200
Don't worry. The phases will be the same.
 
1,948
200
Don't worry. The phases will be the same.
 

sophiecentaur

Science Advisor
Gold Member
23,570
3,964
Don't worry. The phases will be the same.
The reason for the focussing is, in fact, that the phases (path lengths) are the same for all paths. It's jet another way of looking at the process.
 
9
0
THANK YOU, people!!! :D
 

sophiecentaur

Science Advisor
Gold Member
23,570
3,964
In Shreveport Louisiana they have the "Sci-Port" science center. One of the displays they have involves to large parabolic dishes about 6 feet in diameter placed about 20 feet apart. If you and a friend stand in front of each dish, you can speak in a normal voice and clearly hear the other person even across the room thanks to the dishes focusing the sound waves.
I had two 1.2m dishes on opposite walls of my School lab for a few years. Good for sound / ultrasound and microwave experiments. Also very unnerving to walk through some random point in the room and hear some kids voice, loud and right in my ear - they don't only work on - axis.
 

Drakkith

Staff Emeritus
Science Advisor
2018 Award
20,620
4,352
I had two 1.2m dishes on opposite walls of my School lab for a few years. Good for sound / ultrasound and microwave experiments. Also very unnerving to walk through some random point in the room and hear some kids voice, loud and right in my ear - they don't only work on - axis.
Yep.
 

Related Threads for: Focusing sound waves

  • Posted
Replies
7
Views
2K
  • Posted
Replies
4
Views
2K
  • Posted
Replies
10
Views
2K
  • Posted
2
Replies
48
Views
8K
  • Posted
Replies
1
Views
11K
Replies
14
Views
2K
  • Posted
Replies
2
Views
6K
  • Posted
Replies
4
Views
3K

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving

Hot Threads

Top