Summer Project - Replication of MBL loudspeaker 101mkII - Page 5 - diyAudio
Go Back   Home > Forums > Loudspeakers > Planars & Exotics

Planars & Exotics ESL's, planars, and alternative technologies

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
Reply
 
Thread Tools Search this Thread
Old 7th August 2012, 09:20 PM   #41
diyAudio Member
 
Magnasanti's Avatar
 
Join Date: May 2012
Location: Georgia
Send a message via Skype™ to Magnasanti
Quote:
Originally Posted by bear View Post
I would have thought that a spider is mandatory for this driver, no?

How else will it not rock and become un-centered in the gap, and rub??
Usually dome mid-ranges do not utilize a spider. I would guess because the voice coil and dome are one piece, the dome's surround acts on part of the spider. Anyone correct me if i am wrong.
  Reply With Quote
Old 7th August 2012, 09:22 PM   #42
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
not the stock dome midrange unit, the MBL unit, it requires a spider, or are you going to just glue to the dome or dome edge??
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 7th August 2012, 09:46 PM   #43
diyAudio Member
 
Magnasanti's Avatar
 
Join Date: May 2012
Location: Georgia
Send a message via Skype™ to Magnasanti
Quote:
Originally Posted by bear View Post
not the stock dome midrange unit, the MBL unit, it requires a spider, or are you going to just glue to the dome or dome edge??
Sorry i thought you meant the Dayton. Well the plan is to dismantle the Dayton. This would require taking out both the dome/surround and the voice-coil. I will install a new coil and glue my carbon fiber lamellas to the coil. I think i know what you are thinking, but i believe the support rods are there to essentially suspend the sphere in the gap. The lamella group/coil isn’t dropped into the gap. Also mbl uses ferro-fluid in the gap and if used correctly can be used to center the voice-coil.

Last edited by Magnasanti; 7th August 2012 at 09:53 PM.
  Reply With Quote
Old 7th August 2012, 10:14 PM   #44
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
Yes the dayton - but the MBL clone is a different matter.

I do not think that the support rods will play any role in placing the VC in the gap keeping it parallel and centered, unless the construction is very precise.

I'd personally prefer to use a spider to maintain the centering.

If you can manage to produce a melon that is very stable and symmetrical, then perhaps a VC only construction will work, but I find that to be really problematic, and very difficult to do.

Also why use the dayton? I'd want the max flux in the gap, which would require a lot more magnet and motor... although for just proof of concept that doesn't matter.

_-_-bear
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 7th August 2012, 10:23 PM   #45
diyAudio Member
 
Magnasanti's Avatar
 
Join Date: May 2012
Location: Georgia
Send a message via Skype™ to Magnasanti
Quote:
Originally Posted by bear View Post
Yes the dayton - but the MBL clone is a different matter.

I do not think that the support rods will play any role in placing the VC in the gap keeping it parallel and centered, unless the construction is very precise.

I'd personally prefer to use a spider to maintain the centering.

If you can manage to produce a melon that is very stable and symmetrical, then perhaps a VC only construction will work, but I find that to be really problematic, and very difficult to do.

Also why use the dayton? I'd want the max flux in the gap, which would require a lot more magnet and motor... although for just proof of concept that doesn't matter.

_-_-bear
Right this is merely a proof of concept as well as testing different variables,as discussed previously. What i meant to say was that the rods suspend the group in the gap and also might help with centering. I believe the whole assembled unit has to be pretty precise. Also I believe mbl uses the centering force of the ferro-fluid to further help. Producing a "melon that is very stable and symmetrical" is part of the reason, to practice for the real thing.

Last edited by Magnasanti; 7th August 2012 at 10:27 PM.
  Reply With Quote
Old 7th August 2012, 10:42 PM   #46
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
make ur life easy, use a spider?

think about how to keep the walls of the VC parallel to the inner pole piece?

very little is needed to move the vc out of parallel or out of center...

_-_-bear
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 7th August 2012, 10:44 PM   #47
diyAudio Member
 
Magnasanti's Avatar
 
Join Date: May 2012
Location: Georgia
Send a message via Skype™ to Magnasanti
Quote:
Originally Posted by bear View Post
make ur life easy, use a spider?

think about how to keep the walls of the VC parallel to the inner pole piece?

very little is needed to move the vc out of parallel or out of center...

_-_-bear
I will definitely experiment with one.
  Reply With Quote
Old 7th August 2012, 11:44 PM   #48
AVWERK is offline AVWERK  United States
diyAudio Member
 
Join Date: Jan 2004
Location: OC,Calif.
Because of the total weight of the petals and the low frequency filter I don,t see how it will work without a spider.
Those domes aren,t made to function at 80hz or 100hz with any kind of serious travel probably needed to "flex" these big petals. Ferrofluid isn't going to keep it from rubbing at a low frequency
I don,t know what frequency MBL uses but looking at the dual port bandpass design, it can,t be very high.
Do you know what frequency MBL uses and the order? 2nd ,3rd ? for its midrange?

What do think is the reason MBL did not use carbon fiber for this specific driver? Could it be a combination of poor sensitivity and the need for cooling the aluminum petals would provide because of it? It would seem carbon fiber would be a natural here... And yet they didn,t go that direction.. Just speculation on my part.
Maybe a disimilar material connection will be a bad idea resulting in a smoked coil?
Your low frequency and slope will be extremely important if the petals are not capable of disipating any kind of heat.
  Reply With Quote
Old 8th August 2012, 01:23 AM   #49
diyAudio Member
 
Magnasanti's Avatar
 
Join Date: May 2012
Location: Georgia
Send a message via Skype™ to Magnasanti
Quote:
Originally Posted by AVWERK View Post
Because of the total weight of the petals and the low frequency filter I don,t see how it will work without a spider.
Those domes aren,t made to function at 80hz or 100hz with any kind of serious travel probably needed to "flex" these big petals. Ferrofluid isn't going to keep it from rubbing at a low frequency
I don,t know what frequency MBL uses but looking at the dual port bandpass design, it can,t be very high.
Do you know what frequency MBL uses and the order? 2nd ,3rd ? for its midrange?

What do think is the reason MBL did not use carbon fiber for this specific driver? Could it be a combination of poor sensitivity and the need for cooling the aluminum petals would provide because of it? It would seem carbon fiber would be a natural here... And yet they didn,t go that direction.. Just speculation on my part.
Maybe a disimilar material connection will be a bad idea resulting in a smoked coil?
Your low frequency and slope will be extremely important if the petals are not capable of disipating any kind of heat.
I think you have it all wrong. I am not trying to experiment with the "Melon". The big aluminum group. I am using the Dayton for the upper-mid range. This mid-range group operates at 600hz to 3.5khz. All the specifications can be found on post #1.
specifications:

Crossover frequencies: 105Hz, 600Hz, 3.5kHz (Linkwitz-Riley, fourth-order). Acoustic center: 45" (1140mm) from floor. Frequency range: 24Hz–40kHz. Sensitivity: 81dB/2.83V/m. Nominal impedance: 4 ohms. Power handling: 320–500W continuous, 2.2kW peak
  Reply With Quote
Old 8th August 2012, 07:53 AM   #50
el`Ol is offline el`Ol  Germany
diyAudio Member
 
Join Date: May 2005
Location: Bavarian Forest
Quote:
Originally Posted by bear View Post
I would have thought that a spider is mandatory for this driver, no?

How else will it not rock and become un-centered in the gap, and rub??
The DC gold drivers are designed to rub, teflon on teflon is like ice on ice.
  Reply With Quote

Reply


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
Project for next summer. Help needed. osssyvan Full Range 5 25th February 2011 09:22 PM
Possible Summer Project bose301s Multi-Way 8 17th June 2009 11:25 PM
Possible Summer Project bose301s Multi-Way 8 29th May 2009 07:49 PM
Crazy summer project ! guitvinny Everything Else 10 22nd April 2007 08:19 PM
Summer Project edjosh23 Multi-Way 19 9th June 2005 01:37 AM


New To Site? Need Help?

All times are GMT. The time now is 03:50 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2