frequency response of air - diyAudio
Go Back   Home > Forums > General Interest > Everything Else

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 29th February 2004, 09:52 AM   #1
mikelm is offline mikelm  England
diyAudio Member
 
Join Date: May 2003
Location: England
Send a message via Yahoo to mikelm
Default frequency response of air

Does anyone know the frequency response of air and formulas that describe it ?

I was thinking about how much attenuation at different frequencies and different distances from a sound source

mike
  Reply With Quote
Old 29th February 2004, 10:12 AM   #2
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Farfield nearly all sound sources will follow the inverse square law,
this dominates any attenuation or frequency dependent losses.

sreten.
  Reply With Quote
Old 29th February 2004, 10:54 AM   #3
mikelm is offline mikelm  England
diyAudio Member
 
Join Date: May 2003
Location: England
Send a message via Yahoo to mikelm
OK sure, but I wondered within this, wether some frequecies that are attenuated more that others due to the charactoristics of the air.

By way of example, I get the feeling that square wave leading and perhaps trailing edges will be softened with distance.

mike
  Reply With Quote
Old 29th February 2004, 01:52 PM   #4
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Its the different speed of sound through air at different densities
that effectively kills high frequencies through phase interference
and frequency spreading.

A sharp lightening transient will be spread by the different
speeds of sound in the various atmospheric layers, as it
spreads its frequency components wil continually lower,
giving only the rumble effect at long distances.

sreten.
  Reply With Quote
Old 29th February 2004, 01:55 PM   #5
diyAudio Member
 
Join Date: Sep 2002
Location: Sweden
I also think the humidity of the air matters, or at least I get the
impression that higher frequencies are more attenauted when
it is very humid.
  Reply With Quote
Old 29th February 2004, 06:15 PM   #6
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
I think he wants to know about ultrasonics. Like, are they attenuated any more than otherwise?

Speaking of which, something I've always wondered is just how high a frequency can be transmitted acoustically - I know over 100kHz exists!

Tim
__________________
Seven Transistor Labs
Projects and Resources
  Reply With Quote
Old 29th February 2004, 06:19 PM   #7
diyAudio Member
 
Join Date: Sep 2002
Location: Sweden
Quote:
Originally posted by Sch3mat1c

Speaking of which, something I've always wondered is just how high a frequency can be transmitted acoustically - I know over 100kHz exists!
Unless I misremember the figures 300kHz obviously works well
John Iversons ultrasonic speakers?
  Reply With Quote
Old 29th February 2004, 07:04 PM   #8
mikelm is offline mikelm  England
diyAudio Member
 
Join Date: May 2003
Location: England
Send a message via Yahoo to mikelm
Quote:
Originally posted by Sch3mat1c
I think he wants to know about ultrasonics. Like, are they attenuated any more than otherwise?
Not exclusively,

Ideally I would like to see frequency response graphs

10hz - 100khz

at 1 meter, 2m, 3m, 4m, 5m.

what happens to a square wave leading edge would also be interesting.
  Reply With Quote
Old 29th February 2004, 07:17 PM   #9
diyAudio Member
 
Bill Fitzpatrick's Avatar
 
Join Date: Jun 2001
Location: Eugene, OR
Quote:
Originally posted by mikelm


what happens to a square wave leading edge would also be interesting.
Finding the transducer for this would be quite a challenge!
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Frequency response 2litre Analog Line Level 5 31st May 2006 07:00 PM
frequency response pmarcouxx Digital Source 2 20th July 2005 07:43 PM
opt frequency response nkg Tubes / Valves 3 29th August 2004 06:31 AM
Is my frequency response bad? SimontY Multi-Way 21 2nd July 2004 08:44 AM
Doubts on Phase Response and Frequency Response dumrum Multi-Way 11 5th April 2004 10:39 AM


New To Site? Need Help?

All times are GMT. The time now is 11:20 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2