Having one of my stupid thoughts

cradeldorf · 25th June 2011, 01:01 AM

An 18' sub woofer but the coil isn't moving the inside of the cone, The inside of the cone is mounted to the frame. The coil and magnet are on the big diameter of the frame.....somehow......You would get a lot more cone movement that way thus moving more air. Maybe getting it to go at a lower freq. See I told you it was stupid.

60ndown · 25th June 2011, 04:23 AM

my guess is cone movement would be about the same, cones are stiff, you move the middle forward 6mm and the outer edge moves forward 6mm.

i think?

m R g S r · 25th June 2011, 04:34 AM

Some are. Some aren't. Ever see a cone when DC voltage is applied to it? The offset movement is very obvious. This kills drivers pretty quickly however.

chris661 · 25th June 2011, 07:59 AM

Quote:

Originally Posted by cradeldorf

An 18' sub woofer but the coil isn't moving the inside of the cone, The inside of the cone is mounted to the frame. The coil and magnet are on the big diameter of the frame.....somehow......You would get a lot more cone movement that way thus moving more air. Maybe getting it to go at a lower freq. See I told you it was stupid.

Yeah, that could work, buuuut...

If you've gone to the trouble of using such a large coil, why not make the cone even bigger?

DrDyna · 25th June 2011, 02:59 PM

Didn't Morel do something like this?

Conrad Hoffman · 25th June 2011, 03:17 PM

The object is to drive the cone in a manner least apt to cause flex and breakup. That usually means driving it somewhere between the ID and OD. Here's another thought- if you want to drive the OD, it might be easier and cheaper to run an electromagnet around the OD, rather than permanent magnets. It could even have some cool looking fins to keep the windings cool. I've always been surprised that, other than some ancient radios, nobody uses active magnets. There might even be some tricks to drive the magnet from another differential power channel, controlling the current to control the damping of the system. It might be possible to get lower response in a smaller box without gobs of power.

cradeldorf · 26th June 2011, 01:23 AM

What drove me to this is crazy thought was that Damn Thigpen and his Rotary woofer... I Just wonder if theres another way to get down as low as his but with out the complexity of his, and I think the only reason it can get that low is because it's moving way more air..., Just seems like theres should be a different way to achieve those lows without paying 20,000 dollars. .

Wavebourn · 26th June 2011, 02:23 AM

What about an array of motors mounted in circles under flat stiff diaphragm, like some metal foam? Such a huge open baffle, all moving... Like a gong in Buddhist temple...

Richard Ellis · 26th June 2011, 03:45 AM

Kinda like this??

__________________________________________________ _____Rick........

cradeldorf · 26th June 2011, 06:36 AM

Quote:

Originally Posted by Richard Ellis

Kinda like this??

__________________________________________________ _____Rick........

Yep just like that!!!!

25th June 2011, 01:01 AM	#1
cradeldorf diyAudio Member Join Date: Nov 2010	Having one of my stupid thoughts An 18' sub woofer but the coil isn't moving the inside of the cone, The inside of the cone is mounted to the frame. The coil and magnet are on the big diameter of the frame.....somehow......You would get a lot more cone movement that way thus moving more air. Maybe getting it to go at a lower freq. See I told you it was stupid.

25th June 2011, 03:17 PM	#6
Conrad Hoffman diyAudio Member Join Date: Mar 2007 Location: Canandaigua, NY USA	The object is to drive the cone in a manner least apt to cause flex and breakup. That usually means driving it somewhere between the ID and OD. Here's another thought- if you want to drive the OD, it might be easier and cheaper to run an electromagnet around the OD, rather than permanent magnets. It could even have some cool looking fins to keep the windings cool. I've always been surprised that, other than some ancient radios, nobody uses active magnets. There might even be some tricks to drive the magnet from another differential power channel, controlling the current to control the damping of the system. It might be possible to get lower response in a smaller box without gobs of power. __________________ I used to be an audiophool like you but then I took an arrow to the knee.

26th June 2011, 02:23 AM	#8
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	What about an array of motors mounted in circles under flat stiff diaphragm, like some metal foam? Such a huge open baffle, all moving... Like a gong in Buddhist temple... __________________ The devil is not so terrible as his mathematical model! Wavebourn: We Create Creativity!

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
Well I must be stupid then !	nigelwright7557	The Lounge	2	25th July 2010 03:09 AM
New and stupid.	gbeard	Introductions	2	28th December 2007 02:50 AM
This might be stupid but...	CJ900RR	Multi-Way	3	28th April 2006 12:53 AM
This may be stupid but..	skyraider	Digital Source	1	17th December 2004 10:39 AM
....and now for something very stupid.....	bob4	Everything Else	2	23rd December 2002 04:00 PM


	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 June 2011, 04:23 AM	#2
60ndown diyAudio Member Join Date: Apr 2011	my guess is cone movement would be about the same, cones are stiff, you move the middle forward 6mm and the outer edge moves forward 6mm. i think?

25th June 2011, 04:34 AM	#3
m R g S r diyAudio Member Join Date: Jan 2011	Some are. Some aren't. Ever see a cone when DC voltage is applied to it? The offset movement is very obvious. This kills drivers pretty quickly however.

25th June 2011, 02:59 PM	#5
DrDyna diyAudio Member Join Date: May 2007 Blog Entries: 3	Didn't Morel do something like this?

26th June 2011, 01:23 AM	#7
cradeldorf diyAudio Member Join Date: Nov 2010	What drove me to this is crazy thought was that Damn Thigpen and his Rotary woofer... I Just wonder if theres another way to get down as low as his but with out the complexity of his, and I think the only reason it can get that low is because it's moving way more air..., Just seems like theres should be a different way to achieve those lows without paying 20,000 dollars. .

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