adding mass to cone

Endless Lasers · 25th October 2008, 12:20 PM

It is possible to determine the T/S parameters by adding mass to the cone. Is it ever done to add mass permanently. What are the pro's and cons?

gedlee · 25th October 2008, 05:31 PM

Added mass is probably the most common technique. Just make sure that you keep the added mass close to the voice coil connection to the cone. I have used clay but I prefer solder pieces (heavy lead) with a little dry adhesive as it makes a tighter fit to the cone - added mass must be firmly attached to work right.

I have added mass to a speaker in subwoofer apps for example. I just glue on pieces of solder. Balance it as well as possible.

mitchyz250f · 25th October 2008, 10:04 PM

Is there method for calculating the new specs?

speakerdoctor · 25th October 2008, 10:49 PM

Quote:

Originally posted by mitchyz250f
Is there method for calculating the new specs?

I dont' think so. You'll need to run a test with a dedicated woofer tester instrument. They are for sale at PE.
The classic Snell Model A used add mass on the RCF 12 inch woofer. They poured a resin around the porous dust cap to about 1/2 inch depth. It lowers the Fs and efficiency is sacrificed as the trade-off.

gedlee · 25th October 2008, 11:22 PM

Quote:

Originally posted by mitchyz250f
Is there method for calculating the new specs?

If you look up the basic equations for TS parameters its easy to see what added mass will do. It lowers Fs and raises both Qes and Qms.

MJL21193 · 26th October 2008, 12:04 AM

Quote:

Originally posted by speakerdoctor

I dont' think so. You'll need to run a test with a dedicated woofer tester instrument. They are for sale at PE.

There are other options.
For next to nothing with Speaker Workshop and a handful of parts.

Dr.EM · 26th October 2008, 05:17 PM

WinISD Pro can simulate a box and allow you to add mass to the driver to see the effect it will have on the driver in that box. Ideal if your doing a ported or sealed box

HK26147 · 26th October 2008, 05:33 PM

For purposes of testing "poster caulk" ( sold at office supply stores ) works ( see audioXpress November 2008 p 35 ).
Usually 200 grams or less is used.
For permanent application - lead ( as in solder recommended above ).
Also lead foil is sold in golf pro shops

mitchyz250f · 27th October 2008, 12:18 AM

I have the free version of WinISD. How do i make the changes to simulate additional weight?

Moondog55 · 27th October 2008, 01:40 AM

This is just a thought as I've not tried it, but would epoxy with a suitable filler like barium oxide or powdered nickel be any good for adding mass permanently??.
I ask as I still have a litre of West Systems epoxy and powdered aluminium and stainlees stell left over from a heatsink experiment.
Regards
Ted

25th October 2008, 12:20 PM	#1
Endless Lasers diyAudio Member Join Date: Oct 2008	adding mass to cone It is possible to determine the T/S parameters by adding mass to the cone. Is it ever done to add mass permanently. What are the pro's and cons?

25th October 2008, 05:31 PM	#2
gedlee diyAudio Member Join Date: Dec 2004 Location: Novi, Michigan	Added mass is probably the most common technique. Just make sure that you keep the added mass close to the voice coil connection to the cone. I have used clay but I prefer solder pieces (heavy lead) with a little dry adhesive as it makes a tighter fit to the cone - added mass must be firmly attached to work right. I have added mass to a speaker in subwoofer apps for example. I just glue on pieces of solder. Balance it as well as possible. __________________ Earl Geddes Gedlee Website Read about the highly acclaimed Geddes loudspeakers

27th October 2008, 01:40 AM	#10
Moondog55 diyAudio Member Join Date: Jun 2007 Location: Norlane; Geelong: Victoria: Australia	This is just a thought as I've not tried it, but would epoxy with a suitable filler like barium oxide or powdered nickel be any good for adding mass permanently??. I ask as I still have a litre of West Systems epoxy and powdered aluminium and stainlees stell left over from a heatsink experiment. Regards Ted __________________ QUOTE" The more I know, the more I know, I know (insert maniacal laugh >here<) NOTHING"

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Adding cone mass	fdeck	Multi-Way	12	17th June 2009 06:06 PM
Low Qts drivers : Adding mass	316a	Multi-Way	20	4th May 2006 02:27 PM
Can somebody explain the pros/cons of adding cone mass?	GuyPanico	Subwoofers	25	16th April 2005 03:50 AM
Adding mass to PR....	hofffam	Subwoofers	1	7th January 2005 12:01 AM


	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

25th October 2008, 10:04 PM	#3
mitchyz250f diyAudio Member Join Date: Nov 2004 Location: ga	Is there method for calculating the new specs?

26th October 2008, 05:17 PM	#7
Dr.EM diyAudio Member Join Date: Oct 2006 Location: Swindon	WinISD Pro can simulate a box and allow you to add mass to the driver to see the effect it will have on the driver in that box. Ideal if your doing a ported or sealed box

26th October 2008, 05:33 PM	#8
HK26147 diyAudio Member Join Date: Jan 2008	For purposes of testing "poster caulk" ( sold at office supply stores ) works ( see audioXpress November 2008 p 35 ). Usually 200 grams or less is used. For permanent application - lead ( as in solder recommended above ). Also lead foil is sold in golf pro shops

27th October 2008, 12:18 AM	#9
mitchyz250f diyAudio Member Join Date: Nov 2004 Location: ga	I have the free version of WinISD. How do i make the changes to simulate additional weight?

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read