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26th March 2009, 08:09 AM  #1 
diyAudio Member
Join Date: Jan 2006
Location: Tucson, AZ

Cone Excursion
I'm looking for a way to model or plot a speaker's cone excursion versus frequency for a given input power. I realize the cone excursion will depend upon T/S params, enclosure size and type, etc. but I am having a hard time finding an equation that includes all this. I have found PLENTY of references to the loudspeaker design cookbook and the PAR equation but I think it is only valid at the Fc of the system. I need an equation that is valid over all frequencies. Basically, I'm looking for the mathematics behind WinISD's cone excursion plots...Any help would be much appreciated!

29th March 2009, 04:19 PM  #2 
diyAudio Member
Join Date: Jan 2006
Location: Tucson, AZ

Hmmm, 100 views and no replies, this may be more difficult than I thought. I know the cone excursion plot of a sealed enclosure looks like a lowpass filter with the rolloff beginning above the fc of the box. But I'm not exactly sure what the rolloff rate will be or what the excursion will be before the rolloff depending on the input power.

29th March 2009, 05:51 PM  #3 
diyAudio Member
Join Date: Jun 2004
Location: Toronto

I can't answer your question directly, but there is an excellent resource available here:
Linkwitz Labs Electroacoustic models I know that this sight is best known for it's dipole speakers and theory crafting but don't let that throw you off there is plenty of good information to be had here. Near the top of the page at the end of section A1 is a link to a spreadsheet that calculates the one way air displacement required at any frequency. Just at the end of that line there is a link to a GIF file which might provide equations that will eventually give you what you are looking for. This link: Linkwitz Labs Room Acoustics has some good equations for calculating power required to reach a desired output level in a given room. Check Section C5 
5th April 2009, 10:56 AM  #4 
diyAudio Member
Join Date: Feb 2008
Location: Sheffield

WinISD alpha will plot the excursion to frequency graphs for a driver.
Does other things aswell, but you do need to know a lot about your driver...
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5th April 2009, 07:18 PM  #5 
diyAudio Member
Join Date: Sep 2008

Have you checked unibox?
You might be able to figure out the math that drives it. Everything should be there. Not sure how accurate they are, long time since I checked it. 
8th April 2009, 11:47 PM  #6  
diyAudio Member
Join Date: Jun 2002
Location: USA, MN

Quote:
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9th April 2009, 11:08 PM  #7 
diyAudio Member
Join Date: Jun 2002
Location: USA, MN

http://www.diysubwoofers.org/prt/ported3.htm
Note that the Pmax formula calculates power needed to reach excursion (Xmax+15%) Fairly easy to figure out Excursion for a given power from that...
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Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. Carl Sagan Armaments, universal debt, and planned obsolescencethose are the three pillars of Western prosperity. —Aldous Huxley 
10th April 2009, 02:45 AM  #8 
diyAudio Member
Join Date: Jan 2008


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