Upgrading Mordaunt Short MS15 Bookshelves - Page 2 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

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
Reply
 
Thread Tools Search this Thread
Old 21st October 2012, 03:51 PM   #11
xjr100 is offline xjr100  Europe
diyAudio Member
 
Join Date: Sep 2012
Quote:
Originally Posted by system7 View Post
... Been modelling a second order crossover ...
Is it with real drivers measurements?
__________________
Auricap XO, Mundorf, Jantzen capacitors, coils, MSolder, terminals, DH-Labs interconnect & speaker cables, internal wiring for DIY & upgrades are here: www.audiohobby.eu
  Reply With Quote
Old 21st October 2012, 04:21 PM   #12
system7 is offline system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
Quote:
Originally Posted by xjr100 View Post
Is it with real drivers measurements?
Nope. Just trying to sim a paper woofer with similar electrical characteristics and align it for the acoustic centre which you can measure from front of baffle to pole gap.

Bit rough and ready, but hey, what else an you do? Listening tests will show if phase is right, because imaging gets good when it is.

In fact, I'm revising my ideas on this, because the tweeter is not really much like the plastic dome Visaton DT94. I think I'll need more rolloff on the bass. Bass filters are quite predictable, IMO, as long as you account for woofer voicecoil inductance.
__________________
Good Night, and Good Luck. Best regards from Steve in Portsmouth, UK.
  Reply With Quote
Old 21st October 2012, 05:46 PM   #13
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Don't assume the Z plane distance is to VC gap, its usually less than that, closer to 4/5 the cone's depth. That pole gap rough estimation comes from HF drivers and horns pro stuff quick set up practices where the scale and assembly are much different.
  Reply With Quote
Old 21st October 2012, 07:01 PM   #14
system7 is offline system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
Like I say, Salas, it's all a bit rough and ready. Bass filter is going to be 1mH series, 8uF and 2 ohms shunt by the look of it. Had to resolder a broken wire on one tweeter. Teach me to take it apart.

The aerosol carpet glue was more fun than a box of frogs. Most of it went on me! But job done with the rubbery and cork stuff, I think. Waiting for glue to dry.
Attached Images
File Type: jpg Underlay_Artistic_Shot.jpg (100.7 KB, 132 views)
File Type: jpg Floor_Underlay_Loudspeaker.jpg (96.2 KB, 129 views)
__________________
Good Night, and Good Luck. Best regards from Steve in Portsmouth, UK.
  Reply With Quote
Old 21st October 2012, 07:05 PM   #15
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Lets hope that the solvents evaporation won't stone the flowers at least.
  Reply With Quote
Old 21st October 2012, 07:46 PM   #16
diyAudio Member
 
mondogenerator's Avatar
 
Join Date: Sep 2009
Location: City Of Villans
Blog Entries: 1
haha loving the gourmet pasta sauce! Id not considered tomato as an audiophile tool.
__________________
Every new piece of knowledge pushes something else out of my brain - Homer.....................Simpson
  Reply With Quote
Old 21st October 2012, 07:57 PM   #17
diyAudio Member
 
mondogenerator's Avatar
 
Join Date: Sep 2009
Location: City Of Villans
Blog Entries: 1
Quote:
Originally Posted by system7 View Post
Interesting remarks on the tweeter. It looks like it has sharp natural rolloff at 3kHz and at 0.03mH vc inductance and flat won't need a Zobel.
yes the FR looks fairly good. I couldnt find or recall the details at the time, but my comments about the obvious resonance if crossed too low or shallow are still relevant, in my mind at least. I have no idea what causes the effect i perceived. All i know is that i didnt like their low end reproduction. Whilst theyre a classic high value tweeter, they were cheap, so hardly flawless.

To me the most interesting thing about these is the large 'surround'. I often wondered how much contribution it made to the total output. Almost like a 20mm mylar cone tweeter, with all but the center dome covered up.
__________________
Every new piece of knowledge pushes something else out of my brain - Homer.....................Simpson

Last edited by mondogenerator; 21st October 2012 at 08:02 PM.
  Reply With Quote
Old 21st October 2012, 09:35 PM   #18
system7 is offline system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
Got them back together with the cabinet changes.

4.5mm rubber and cork panel damping underlay on the top, bottom and sides. A single sheet of BAF wadding on the back. The BBC idea is you add damping to the smaller, more rigid panels. The front and back panels will flex more with added mass, so don't damp them.

Bass is LOVELY and smooth and deep, 4cm from the back wall as recommended. Midrange seems to have more detail. The side panels are a lot more inert. This is really what you'd do with bass reflex on accepted ideas, but this is closed box.

The top end is still letting things down a bit. Sibilant. Might be dried-up ferrofluid, or the cheap tweeter itself because the treble crossover is OK. More work to do. Enjoying this.
Attached Images
File Type: jpg Mordaunt_Short_MS15_Wadding_and_Damping.jpg (88.2 KB, 115 views)
__________________
Good Night, and Good Luck. Best regards from Steve in Portsmouth, UK.
  Reply With Quote
Old 29th October 2012, 03:24 PM   #19
system7 is offline system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
After extended listening, I have put all the the wadding back in the (closed box) cabinets. It's one of those tradeoffs that seem abound in audio, and a bit frustrating TBH.

The speakers were just TOO LIVELY without it, and fatiguing in the midrange to listen to. Maybe it's the paper bass and the lack of rolloff in the cone-breakup region due to the simple single coil bass crossover.

Maybe what I have done is balance the relatively lively paper bass with heavy damping from the wadding. It might work better with less wadding on a plastic cone. This is a shame though, because the bass is just not as clear with all the wadding.

Ah well. They are decent little speakers anyway, but I don't think I want to fiddle with them any more. Other fish to fry.
__________________
Good Night, and Good Luck. Best regards from Steve in Portsmouth, UK.
  Reply With Quote
Old 29th October 2012, 03:28 PM   #20
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
Quote:
Originally Posted by system7 View Post

Maybe what I have done is balance the relatively lively paper bass with heavy damping from the wadding. It might work better with less wadding on a plastic cone. This is a shame though, because the bass is just not as clear with all the wadding.
Then measure them and find out. If this is the case then the crossover is not adequate and needs modification. Get the xover right and then you can go with the optimum amount of damping material for the cabinet alignment.
__________________
What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz!
  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
Audioson Kirksaeter or Mordaunt Short digits Multi-Way 1 30th May 2011 05:25 AM
Mordaunt Short question mochame Full Range 4 3rd February 2010 07:05 PM
MORDAUNT-SHORT 302 AVANT bookshelves - are these any good? MikeHunt79 Multi-Way 2 8th May 2008 05:09 PM
Mordaunt Short tweeter busoni Multi-Way 7 9th January 2008 03:23 PM
Mordaunt Short brainteaser... REDSKIN Multi-Way 7 10th February 2005 12:09 AM


New To Site? Need Help?

All times are GMT. The time now is 10:49 PM.


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