Increase cone mass to rid cone resonance; worth it? - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

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
Thread Tools Search this Thread
Old 30th July 2010, 03:25 AM   #1
diyAudio Member
Join Date: Jan 2009
Location: Decatur, Al
Default Increase cone mass to rid cone resonance; worth it?

Due to cone resonance of a driver (scan 18w/4), I'm considering ways of adding mass to the cone itself.
I've tried raising/lowering qts via series resistors and AP mat tuning, but the problem always rears it's head with lower bass guitar and I've narrowed it down to ~71hz notes. I'm considering adding mass to the cone and hopefully bring the resonance to a point outside the passband (60hz).
I am aware that adding mass will raise qts (a benefit in my install) and decreases sensitivity (not a problem; plenty of power on tap and actively processed).

Driver is pretty much a 'throw away' and I figure it's a good chance to experiment with adding mass to the cone to see if it breaks up the resonance.
I've seen mention of using epoxy/resin combos, lead weights with glue, etc. Not sure of the effect on various types of glue on a paper cone, though.

I've got viscoelastic material (sound deadener) laying around. Was even considering cutting 4 very small pieces of equal size and attaching that to the back of the cone, symmetrically.

I typically try crap anyway and learn as I go, but in this case, I'm open to suggestions. So, any 'hey, DON'T do this:' suggestions?
  Reply With Quote
Old 30th July 2010, 03:40 AM   #2
sreten is offline sreten  United Kingdom
diyAudio Member RIP
Join Date: Nov 2003
Location: Brighton UK

71Hz is an issue ? Far more likely a room issue than a driver issue.
Room mode analysis and then optimum placement are better bets.

Most drivers are optimised for purpose, mods only change the purpose.

  Reply With Quote
Old 30th July 2010, 03:50 AM   #3
diyAudio Member
Join Date: Jan 2009
Location: Decatur, Al
it's a cone resonance issue; no doubt. After nearly a year of trying to figure it out I'm 100% sure that's the issue.

You can hear it pull straight to the floor and can feel the floor resonate. Not an enclosure issue. Nothing in the floor is causing the resonance (ie: no rattles).

FWIW, this is a car audio install.
I understand changing the mms means changing the FR. This driver's puprose is for midbass and is playing 60-250. As I said, it's pretty much a throw away driver at this point (beat up and won't sell anyway) so it's an option I want to explore.

I understand trying to get to the root of the problem, but I've gotten to it. Short of buying new drivers to fit the bill (no $$$) this is kind of my last option.


Last edited by bikinpunk; 30th July 2010 at 03:54 AM.
  Reply With Quote
Old 30th July 2010, 07:10 AM   #4
rabbitz is offline rabbitz  Australia
diyAudio Member
rabbitz's Avatar
Join Date: Jul 2003
Location: Newcastle, Australia
I know Legend Acoustics in Australia used strips of balsa on the back of the the older 18W8545 drivers.
Attached Images
File Type: jpg legend_note.jpg (66.2 KB, 95 views)
No longer DIY active
  Reply With Quote
Old 30th July 2010, 09:50 AM   #5
diyAudio Member
Join Date: Sep 2008
"You can hear it pull straight to the floor and can feel the floor resonate."

Then you hit the floors resonant frequency. You can't really blame the driver for that.

If you have a mass coupling between the enclosure ant cone that the easiest to change is the enclosure. Add a big weight on top of it and check what happens.

Any measurements would be useful, can't really tell what's going on from your description. And guessing isn't the way to solve a problem like this.
  Reply With Quote
Old 30th July 2010, 11:43 AM   #6
AndrewT is offline AndrewT  Scotland
diyAudio Member
Join Date: Jul 2004
Location: Scottish Borders
cone resonance due to breakup modes is more likely up in the low kHz region.
A low frequency resonance cannot be due to cone breakup modes.

Altering the moving mass of the driver will alter the way it is tuned.
Listen to what they are telling you.
regards Andrew T.
Sent from my desktop computer using a keyboard
  Reply With Quote
Old 30th July 2010, 05:08 PM   #7
diyAudio Member
Join Date: Jan 2009
Location: Decatur, Al
the floors are COVERED in clay+lead shot as well as multiple layers of viscoelastic material. COVERED. I'm talking 8 lbs to each side. The enclosure's baffle has about 2lbs on it. The problem didn't go away with that.

Thanks. I'll consider other options.
  Reply With Quote


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
adding mass to cone Endless Lasers Multi-Way 17 4th October 2012 08:39 PM
Question--Cone mass Parasonic Full Range 4 15th April 2010 12:43 AM
Adding cone mass fdeck Multi-Way 12 17th June 2009 06:06 PM
Dampen metal cone resonance: How much is enough? gary f Multi-Way 33 14th February 2009 04:53 PM
Can somebody explain the pros/cons of adding cone mass? GuyPanico Subwoofers 25 16th April 2005 03:50 AM

New To Site? Need Help?

All times are GMT. The time now is 03:10 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2