Cone Excursion

johnc124 · 26th March 2009, 08:09 AM

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!

johnc124 · 29th March 2009, 04:19 PM

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 low-pass filter with the roll-off beginning above the fc of the box. But I'm not exactly sure what the roll-off rate will be or what the excursion will be before the roll-off depending on the input power.

trans192 · 29th March 2009, 05:51 PM

I can't answer your question directly, but there is an excellent resource available here:

Linkwitz Labs Electro-acoustic 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

chris661 · 5th April 2009, 10:56 AM

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...

David_Web · 5th April 2009, 07:18 PM

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.

Ron E · 8th April 2009, 11:47 PM

Quote:

Originally posted by johnc124
Hmmm, 100 views and no replies, this may be more difficult than I thought.

For the most part, if you are smart enough to need the formula, you ought to be smart enough to figure it out or figure out where to get it. It's kind of a PITA to post complex formulas, and most people aren't gonna spend a half hour of their day posting something that you may or may not be able to use.

Ron E · 9th April 2009, 11:08 PM

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...

HK26147 · 10th April 2009, 02:45 AM

The Linkwitz site also has this:

http://http://www.linkwitzlab.com/im...edge-micro.gif

26th March 2009, 08:09 AM	#1
johnc124 diyAudio Member Join Date: Jan 2006 Location: virginia	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!

5th April 2009, 10:56 AM	#4
chris661 diyAudio Member Join Date: Feb 2008 Location: Lancashire Blog Entries: 7	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... __________________ "Throwing parts at a failure is like throwing sponges at a rainstorm." - Enzo My setup: http://www.diyaudio.com/forums/multi...tang-band.html

9th April 2009, 11:08 PM	#7
Ron E 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... __________________ Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan Science is a way of thinking much more than it is a body of knowledge. --Carl Sagan

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29th March 2009, 04:19 PM	#2
johnc124 diyAudio Member Join Date: Jan 2006 Location: virginia	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 low-pass filter with the roll-off beginning above the fc of the box. But I'm not exactly sure what the roll-off rate will be or what the excursion will be before the roll-off depending on the input power.

29th March 2009, 05:51 PM	#3
trans192 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 Electro-acoustic 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, 07:18 PM	#5
David_Web 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.

10th April 2009, 02:45 AM	#8
HK26147 diyAudio Member Join Date: Jan 2008	The Linkwitz site also has this: http://http://www.linkwitzlab.com/im...edge-micro.gif

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