Hello, and upgrading Mission 71i speakers - 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 14th August 2004, 08:09 PM   #1
diyAudio Member
 
Join Date: Jun 2004
Location: North West
Default Hello from the UK

Hi everyone!

I am a total newbie to all this DIY/modding stuff and glad I bumped into this site. It certainly seems very active regarding this field and from what I've read you guys are very knowledgeable. It certainly gives me alot to think about and opens a new door into the world of diy audio as opposed to buying ready made stuff off the shelf.

Ok on to my question:

I was wondering if you guys would be kind enough to point me in the right direction regarding the upgrading of components on the second order crossovers on my Mission M71i speakers. I realise it's a basic question and they are not so great speakers and it's not entirely DIY but it is my first project and I would like to see what kind of improvements can be gained from adding better quality parts (would like to limit spending to about 30-40 for the pair). So does anybody know if there are any sites out there that can help a total novice to understand and upgrade the crossovers components and what parts would be best to use (not overkill considering the quality of drivers used). I've read some of the threads in the loudspeaker section but the posts seem to be more for people with some knowledge.

Thanks!

BTW most of the parts are unbranded except the caps (C2+C3 are elytone 10uF (10%) 63V NP, R1 is 5W 2.7ohms JB, R2 is 5W 2.2ohms JF, C1 is 5.6K 100V). Don't laugh but this stuff doesn't mean a thing to me.
  Reply With Quote
Old 15th August 2004, 07:40 AM   #2
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
Hi Mate , and welcome to diyAudio

I have moved your post to the loudspeakers section, and retitled it, as your questions will be better answered there.

For a first suggestion for your upgrade question, you might want to open the speakers up and have a look at the size/type of components in there, as most of the upgrade components are significantly larger than stock items. Draw a circuit diagram if you can trace all the connections, that will make things easier for others to help you, and also help your understanding of what is going on.
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 15th August 2004, 04:15 PM   #3
diyAudio Member
 
leadbelly's Avatar
 
Join Date: Dec 2002
Location: Calgary, Alberta
Hope you don't consider this threadjacking, but since I have 6 M70 speakers and have considered posting such a question, I thought I would throw it in:

Click the image to open in full size.

Click the image to open in full size.

Looks like a basic cheapo xover; what's best bang-for-buck upgrade?
__________________
Aerodynamics are for people who can't build engines. Enzo Ferrari
  Reply With Quote
Old 15th August 2004, 04:36 PM   #4
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
Well it looks as if you have a nice air core inductor on the bass driver which doesnt need replacing.

It looks like a first order slope on the tweeter and looks to have a cap thats better then a nasty non polarised electrolytic, the black cylinder on its side at the top of the xover board. Unless its a continuation of the terminal cup.

In anycase I would guess the blue non polar electrolytics you can see are either zobels or shunt capacitors and you wont really get much benafit from replacing them because they are not directly in the signal path.

The resistors are good too.

I would say your best bet is replace any capacitors that are in the signal path with a good quality ones.
__________________
What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz!
  Reply With Quote
Old 15th August 2004, 05:42 PM   #5
diyAudio Member
 
leadbelly's Avatar
 
Join Date: Dec 2002
Location: Calgary, Alberta
No, the black thing is the inductor on the woofer. I've sketched it out to make it clearer:

Click the image to open in full size.
__________________
Aerodynamics are for people who can't build engines. Enzo Ferrari
  Reply With Quote
Old 15th August 2004, 06:19 PM   #6
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
Ah well that helps a lot, show you guess work isnt always correct!

OK well its a second order on the woofer with a bit of extra damping (the 1R resistor)

And again second order on the tweeter 2r2 providing a small amount of padding.

OK well with that in mind, leave the inductors where they are, cored inductors are not bad by any means, the only major problem they suffer is saturation before an air core would. But these speakers can probably only handle a small amount of power anyway, so coil saturation is unlikely going to happen.

The resistors, as stated before are fine and dont need to be touched.

The capacitors are less then ideal, replace the one in the signal path to the tweeter with a polyprop from say wilmslow audio.

Capacitors in shunt areas dont affect the sound anywhere near as much as caps in the signal path, you could alter the ones in the shunt section of the woofers xover if you wanted to, but due to the quality of the woofer its probably not worth it.

So like before just change the cap in the tweeter signal path to something better.

The final step would be to actually measure the drivers for both impedance and frequency in the mission boxes and first simulate what the xovers mission has built does, and then either leave the xover alone, because mission have done a good job. Or make a new xover yourself.

Chances are mission have been stingey on bafflestep to increase quoted sensativity, so a redesign could give you a more pleasing tonal balance, if you dont like what you already have.

A complete redesign seems a little overkill for such a cheap pair of speakers because it would likely cost half the price of the speakers anyway to redo the xover with quality parts.
__________________
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
Mission 737 speakers Skorpio Multi-Way 6 29th June 2007 07:41 AM
Mission speakers repair. edhardie Multi-Way 5 3rd January 2006 10:09 PM
Upgrading my set with some DIY speakers? Dinobe Multi-Way 8 25th August 2004 08:59 AM
Mission 702 speakers on Aleph 5 vossie Pass Labs 5 13th January 2003 12:06 PM
open mission speakers fezz Multi-Way 2 25th March 2002 01:32 PM


New To Site? Need Help?

All times are GMT. The time now is 04:03 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