Foro Flamenco
Posts Since Last Visit | Advanced Search | Home | Register | Login

Today's Posts | Inbox | Profile | Our Rules | Contact Admin | Log Out



Welcome to one of the most active flamenco sites on the Internet. Guests can read most posts but if you want to participate click here to register.
This site is dedicated to the memory of Paco de Lucía, Ron Mitchell, Guy Williams, Linda Elvir, Philip John Lee and Craig Eros who went ahead of us too soon.
We receive 12,200 visitors a month from 200 countries and 1.7 million page impressions a year. To advertise on this site please contact us.





Interested in science? please read, its important (to me)   You are logged in as Guest
Users viewing this topic: none
  Printable Version
All Forums >>Discussions >>Off Topic >> Page: [1]
Login
Message<< Newer Topic  Older Topic >>
 
XXX

Posts: 4400
Joined: Apr. 14 2005
 

Interested in science? please read, ... 

One question is bugging me since years.

By definition, the energy of a wave is proportional to its frequency, the higher the frequency, the higher quantum of energy the wave is transporting, right?

BUT, if your neighbor is listening to music for example, it is always the low frequencies you will hear, ie the basses that permeate the wall. So, why do walls absorb high frequencies better than low ones, although latter ones transport less energy?

_____________________________

Фламенко
  REPORT THIS POST AS INAPPROPRIATE |  Date Mar. 6 2011 16:06:29
 
NormanKliman

Posts: 1143
Joined: Sep. 1 2007
 

RE: Interested in science? please re... (in reply to XXX

Not sure but maybe you'll find information here.

_____________________________

Be here now.
  REPORT THIS POST AS INAPPROPRIATE |  Date Mar. 6 2011 17:40:46
 
XXX

Posts: 4400
Joined: Apr. 14 2005
 

RE: Interested in science? please re... (in reply to NormanKliman

Thx i didnt expect an answer so soon! :)

quote:

Figure 6: The higher frequencies (top) are absorbed well because their velocity peaks fall within the material thickness. The lower frequency at the bottom does not achieve as much velocity so it's absorbed less.


This seems to be the answer! I still have to read everything in detail but i have a feeling this is it.

_____________________________

Фламенко
  REPORT THIS POST AS INAPPROPRIATE |  Date Mar. 6 2011 19:15:08
 
elgreco

Posts: 247
Joined: Nov. 24 2010
From: San Francisco CA

RE: Interested in science? please re... (in reply to XXX

Hi Deniz,

I think it is the same reason that you get a better signal from FM than AM. The bigger the wave the easier it is to get through matter. It can find more free space and large parts of it penetrate. Higher frequency means shorter wavelength, hence if it hits an obstacle it gets stuck.

D.

_____________________________

Captain Esteban: Caballeros! I believe you all know each other?
Don Diego from San Fernando.
Don Francisco from San Jose.
Don Fernando from San Diego.
Don Jose from San Bernardino.
Luis Obispo from Bakersfield.
  REPORT THIS POST AS INAPPROPRIATE |  Date Mar. 6 2011 21:40:38
 
hamia

 

Posts: 378
Joined: Jun. 25 2004
 

RE: Interested in science? please re... (in reply to elgreco

quote:

ORIGINAL: elgreco

Hi Deniz,

I think it is the same reason that you get a better signal from FM than AM. The bigger the wave the easier it is to get through matter. It can find more free space and large parts of it penetrate. Higher frequency means shorter wavelength, hence if it hits an obstacle it gets stuck.

D.



FM=frequency modulation, AM=amplitude modulation. So in AM the amplitude of the signal is being varied (in order to carry the signal information) whereas in FM the frequency is varied. This is why AM is not so good as FM.

Penetration of an acoustic wave through a medium depends on various things. The proportion of energy transmitted/reflected at a boundary is dependent on the acoustic impedance change between one type of material and another (also the angle of incidence). At an interface with a high AI change most of the energy will be reflected and not much will pass through. Eg a sound going from water to air will be almost 100% reflected back due to the high AI contrast between water and air. Same for air to concrete. Materials with similar AI will allow more energy to propagate from one material to the other.

Energy loss (which is separate from the loss due to reflection) depends on the number of cycles / unit distance. So for example, 100 cycles per 100m will lose much more energy than 1 cycle per unit energy. This energy is lost as heat.
  REPORT THIS POST AS INAPPROPRIATE |  Date Mar. 7 2011 10:00:20
 
elgreco

Posts: 247
Joined: Nov. 24 2010
From: San Francisco CA

RE: Interested in science? please re... (in reply to hamia

Thanx Hamia,

You brought back physics flashbacks from my undergrad years of so looong ago...!

:)
Dinos

_____________________________

Captain Esteban: Caballeros! I believe you all know each other?
Don Diego from San Fernando.
Don Francisco from San Jose.
Don Fernando from San Diego.
Don Jose from San Bernardino.
Luis Obispo from Bakersfield.
  REPORT THIS POST AS INAPPROPRIATE |  Date Mar. 7 2011 16:59:55
Page:   [1]
All Forums >>Discussions >>Off Topic >> Page: [1]
Jump to:

New Messages No New Messages
Hot Topic w/ New Messages Hot Topic w/o New Messages
Locked w/ New Messages Locked w/o New Messages
 Post New Thread
 Reply to Message
 Post New Poll
 Submit Vote
 Delete My Own Post
 Delete My Own Thread
 Rate Posts


Forum Software powered by ASP Playground Advanced Edition 2.0.5
Copyright © 2000 - 2003 ASPPlayground.NET

0.046875 secs.