Help An Absolute Beginner With A Unique Project? - 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 29th November 2014, 11:25 PM   #1
diyAudio Member
 
Join Date: Apr 2013
Default Help An Absolute Beginner With A Unique Project?

OK...here goes: I've had an interest, in trying my hand at some builds; as I love the hobby, the idea of experimenting with various raw drivers...and my brother has some woodworking knowledge.

Problem is...I'm an amateur, and haven't honed my box-making skills just yet; plus...I'm sure there's more to making a decent-sounding speaker, than just a good box...and slapping random drivers into it.

Obviously, I know nothing of volume, acoustics, damping, cross-over design, etc. All that being said...I had a unique opportunity, that I could not pass on. My buddy and I own, and love PMC FACTs (I, 3s...and he 8s, soon to be 12s); and we found a pair of authentic cabinets, for sale...sans drivers, cross-over, and speaker terminals/back-plate.

Click the image to open in full size.

So...for this build, luckily...we don't need to worry about cabinet volume, and damping; that's been done for us!! I actually thought, picking the drivers would be pretty easy too.

Being PMC fans, I know they design their drivers...to be manufactured by SEAS. To look at them...I thought these would be most closely suited https://www.madisoundspeakerstore.co...r-cone-woofer/ ; but a) these speakers were pre-drilled for 4 mount-screws, and these SEAS drivers have 6 (not that an issue like that couldn't be overcome), and b) these drivers have a surround that measures 146mm; whereas the specs, put the "actual" drivers at 140mm (and I've measured the cut-outs, as best I could...albeit crudely; and it seems to be 5.5" on the nose).

On the bright side...it does look like, any number of SEAS Prestige tweeter will fit https://www.madisoundspeakerstore.co...tweeters-seas/ ; and my buddy and I, are giving thought...to using the Madisound cross-over service https://www.madisoundspeakerstore.co...-by-madisound/ (for the record...The Sound Org, offered to sell us "authentic" cross-over, and/or back-plates with terminals. $3800 for a pair of cross-over, and a cool $5 big-ones even, for the cross-over and back-plate )

So what do you say guys; give me a hand with this? Many people warned me, maybe I should seek out...a forum, that was perhaps a bit more tolerant of a complete newbie. But I figured if I came hat in hand, admitted I don't know $h!t; prepared you for the fact that I will ask a ton of stupid questions, in order to understand why...and at least have some input, into my own build (rather than just follow advice blindly). I thought you might be up for the challenge?

So...where to even start; what's the first step??
  Reply With Quote
Old 30th November 2014, 12:21 AM   #2
DUG is offline DUG  Canada
diyAudio Member
 
Join Date: Jan 2003
Location: mississauga ontario canada
The first step (IMHO) would have been to pick your drivers and then calculate the enclosure size.

You will now have to pick some drivers and calculate the enclosures needed for them and see which ones match.

I have done that for a replacement woofer for a friend...had to go to sealed but sounds OK.
__________________
Doug We are all learning...we can all help
"You can't stop the signal, Mal. Everything goes somewhere..."
  Reply With Quote
Old 30th November 2014, 12:28 AM   #3
diyAudio Member
 
Join Date: Apr 2013
OK Doug, thanks; but with the understanding of why, in this particular case, I had to work "backwards" so to speak. What would be my first step?
  Reply With Quote
Old 30th November 2014, 12:54 AM   #4
diyAudio Member
 
Join Date: Nov 2012
Location: Brasil
My advice it's to pick some of my drivers and save money, projects with them you will find a lot, try troels gravensen site.
  Reply With Quote
Old 30th November 2014, 02:13 AM   #5
system7 is offline system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
Location: Portsmouth UK
What is the tweeter cutout? 98mm or 104mm? Has the look of a SEAS 22TAF/G.
H1283-06 22TAF/G

Those woofers look more like ScanSpeak W15/8434G-00 or Vifa PL14WJ on 149mm cutout:
https://www.madisoundspeakerstore.co....25-midwoofer/

Conceivably SB Acoustics:
SB Acoustics :: 5" SB15NRXC30-8

Plenty of kit ideas about:
Vifa PL14WJ-
SB Acoustics :: Elok

Should be a doddle really!
__________________
Best Regards from Steve in Portsmouth, UK.
  Reply With Quote
Old 30th November 2014, 02:36 AM   #6
diyAudio Member
 
Join Date: Apr 2013
Quote:
Originally Posted by system7 View Post
What is the tweeter cutout? 98mm or 104mm? Has the look of a SEAS 22TAF/G.
H1283-06 22TAF/G

Those woofers look more like ScanSpeak W15/8434G-00 or Vifa PL14WJ on 149mm cutout:
https://www.madisoundspeakerstore.co....25-midwoofer/

Conceivably SB Acoustics:
SB Acoustics :: 5" SB15NRXC30-8

Plenty of kit ideas about:
Vifa PL14WJ-
SB Acoustics :: Elok

Should be a doddle really!
Thanks for weighing-in! The tweeter, is definitely just under 4"; so must be ~98mm. So yes...I'll have my eye on this? https://www.madisoundspeakerstore.co...22tff-tweeter/

I looked at the SB Acoustics drivers; and ScanSpeak (because you're right...they have the look, and 4 mounting-screws)...but they're surrounds are ~150mm.

Last edited by CDLehner; 30th November 2014 at 02:45 AM.
  Reply With Quote
Old 30th November 2014, 12:56 PM   #7
system7 is offline system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
Location: Portsmouth UK
AW, mate! This is a flippin' nightmare!

You need drivers with a 140mm round chassis, and they really don't make 'em any more, since the famous Vifa P13WH polycone was discontinued.

You've got no margin to make the holes bigger either. The only current good drivers I could find were the Audax HM130Z0 Aerogel 13cm 5.25" woofer or the SPH-135/AD with a bit of carpentry, but that won't look very nice.

I don't think this looks very good at all, unless PMC will help you out. Where did the cabinets come from anyway? It's a current model, and I can't see PMC dumping them.
__________________
Best Regards from Steve in Portsmouth, UK.
  Reply With Quote
Old 30th November 2014, 01:18 PM   #8
ODougbo is offline ODougbo  United States
diyAudio Member
 
Join Date: Aug 2011
Location: Maryland USA
The cross-over service mentioned in most cases is a starting point only.
From there you would need mic & measure and make further xo adjustments.

What model PMC are they? Did you mention that, maybe you can find a deal on the web i.e. old sun-burnt cabs with good drivers.
  Reply With Quote
Old 30th November 2014, 03:28 PM   #9
system7 is offline system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
Location: Portsmouth UK
Crossovers depend on the skill of the concept, IMO. There are good and bad sounding circuits which measure much the same. Some drivers play nicely together too, others don't.

But anyway, all is not lost. I have found a couple of midbasses that just about fit. AND some designs for them by VERY talented people. Which gives a point of departure.

138mm.
https://www.madisoundspeakerstore.co...ne-mid/woofer/

This is by Michael Chua: "SWIFT" (ZAPH ZA14 + VIFA XT25) Monitors by AmpsLab

142mm.
https://www.madisoundspeakerstore.co...1/2-wool-cone/

This by Paul Carmody: https://sites.google.com/site/undefi...-orientexpress
__________________
Best Regards from Steve in Portsmouth, UK.
  Reply With Quote
Old 1st December 2014, 01:29 AM   #10
diyAudio Member
 
Join Date: Apr 2013
Quote:
Originally Posted by ODougbo View Post
The cross-over service mentioned in most cases is a starting point only.
From there you would need mic & measure and make further xo adjustments.

What model PMC are they? Did you mention that, maybe you can find a deal on the web i.e. old sun-burnt cabs with good drivers.
FACT 3s

Quote:
Originally Posted by system7 View Post
Crossovers depend on the skill of the concept, IMO. There are good and bad sounding circuits which measure much the same. Some drivers play nicely together too, others don't.

But anyway, all is not lost. I have found a couple of midbasses that just about fit. AND some designs for them by VERY talented people. Which gives a point of departure.

138mm.
https://www.madisoundspeakerstore.co...ne-mid/woofer/

This is by Michael Chua: "SWIFT" (ZAPH ZA14 + VIFA XT25) Monitors by AmpsLab

142mm.
https://www.madisoundspeakerstore.co...1/2-wool-cone/

This by Paul Carmody: https://sites.google.com/site/undefi...-orientexpress
Thanks; I saw the Zaph drivers, and noticed their 139mm diameter as well. Of course, I didn't want to pick drivers...just based on size.

I guess one of the questions, I was looking to have answered here; was...just how big a deal, is say ~6mm? (The SEAS drivers measure 146mm)
  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
Absolute Beginner to SPICE klewis Solid State 19 12th April 2009 07:01 PM
Absolute beginner- advice please H Fiddlefinger Introductions 1 9th June 2008 02:40 PM
Absolute beginner vs Andromeda speakers.. Marcopacio Multi-Way 16 3rd August 2007 05:46 AM
Cutting, drilling, mounting etc. for the absolute beginner unhinged Everything Else 608 2nd July 2006 11:50 PM


New To Site? Need Help?

All times are GMT. The time now is 08:59 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2