Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

Dunlavy SC IV schematics ?
Dunlavy SC IV schematics ?
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 15th July 2018, 11:36 AM   #1
Old'n'Cranky is offline Old'n'Cranky  Australia
diyAudio Member
 
Join Date: Aug 2009
Default Dunlavy SC IV schematics ?

A friend has just bought a pair of Dunlavy SC-IV's.
The earlier versions, not the later 'A's.
But I believe these have been updated with Morel tweeters.

I'm hoping someone has the schematic they can share.

All I've found so far are photos of what looks like potentially two minor variations.
  Reply With Quote
Old 15th July 2018, 11:48 AM   #2
mickiboi007 is offline mickiboi007  Australia
diyAudio Member
 
Join Date: May 2017
Location: Earth
If they were my speakers I would forget all about the passive crossovers and go fully active.
  Reply With Quote
Old 15th July 2018, 06:34 PM   #3
digitalthor is offline digitalthor  Denmark
diyAudio Member
 
Join Date: Jan 2018
Quote:
Originally Posted by mickiboi007 View Post
If they were my speakers I would forget all about the passive crossovers and go fully active.
+1
  Reply With Quote
Old 23rd December 2018, 11:41 PM   #4
Old'n'Cranky is offline Old'n'Cranky  Australia
diyAudio Member
 
Join Date: Aug 2009
Update.
Friend asked me to babysit these speakers.
And after getting his blessings I removed one crossover and took many pics.
I have also now drawn up the crossover.

Due to technological advances, there is much room for improvement.
If he decides to go that way that is.....
Attached Images
File Type: jpg sc iv.jpg (735.4 KB, 863 views)
File Type: jpg Dunlavy SC IV.jpg (81.3 KB, 891 views)
  Reply With Quote
Old 24th December 2018, 12:29 AM   #5
Cask05 is offline Cask05  United States
diyAudio Member
 
Cask05's Avatar
 
Join Date: Nov 2007
Location: Arlington, TX
Quote:
Originally Posted by mickiboi007 View Post
If they were my speakers I would forget all about the passive crossovers and go fully active.
I would tend to agree. Here is a quote from this site:

Quote:
...the pair of SC-VIs that I purchased for personal use spent about THIRTY HOURS in the anechoic chamber. Every single pair of speakers he built went into the chamber, one speaker at a time and unlike most other speaker companies, each crossover was hand built for that specific speaker and set of drivers and unless John personally examined the chamber results, the speaker would not ship...
This isn't what I'd call "design for six sigma" (DFSS), if you catch my drift...

Chris
  Reply With Quote
Old 24th December 2018, 03:27 AM   #6
Patrick Bateman is offline Patrick Bateman  United States
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
Quote:
Originally Posted by Old'n'Cranky View Post
Update.
Friend asked me to babysit these speakers.
And after getting his blessings I removed one crossover and took many pics.
I have also now drawn up the crossover.

Due to technological advances, there is much room for improvement.
If he decides to go that way that is.....
Click the image to open in full size.

Click the image to open in full size.

Thank you! That is one heck of an inductor!
  Reply With Quote
Old 24th December 2018, 04:30 AM   #7
Old'n'Cranky is offline Old'n'Cranky  Australia
diyAudio Member
 
Join Date: Aug 2009
Welcome.

Bass inductor is a reasonable size.
8.2mH 0.8ohm 14awg.
But I'd still use something with lower dcr.
As I say, room for improvements.

But it's the owners call if he wants to go that way.
  Reply With Quote
Old 24th December 2018, 09:07 AM   #8
wesayso is online now wesayso  Netherlands
diyAudio Member
 
wesayso's Avatar
 
Join Date: Jul 2007
Is the balance off? Dunlavy sure new what he was doing, I wouldn't claim to be able to do better. The changed out tweeter might have upset things though.
This is pretty much a unique speaker with a clear vision, it would be a shame to mess it up. Just read the post from Cask05 above.


Please read the paper by John Dunlavy to get what he was going for. I'll send you a link trough PM. There's also lots of info including interviews on Stereophile.
Dunlavy Audio Laboratories SC-IV loudspeaker | Stereophile.com

Dunlavy Audio Labs Signature SC-VI loudspeaker | Stereophile.com

Must read interview with John Dunlavy
__________________
Use Science to design your speakers and they will sound like a piece of Art...
  Reply With Quote
Old 24th December 2018, 10:44 AM   #9
Cask05 is offline Cask05  United States
diyAudio Member
 
Cask05's Avatar
 
Join Date: Nov 2007
Location: Arlington, TX
A quote from Mr. Dunlavy from that last linked Stereophile article:

Quote:
You could have a speaker that makes ±1dB, for example. And you say, "Gosh, how can you better that?" But what if it's +1dB over an octave and a half, say from 1-2.5kHz? And then it suddenly jumps down to -1dB, for a total change of 2dB, for the next octave? You're going to hear a spectral imbalance. The specs might look great—golly, here's a speaker that measures ±1dB—but it's not going to sound nearly as good as a speaker that is up and down 1dB every third of an octave. In the real world we're used to hearing that—reflections from the walls of the room cause similar variations—and we tune that out.

It may come as a surprise—this is giving away a trade secret—but when I design a loudspeaker, I first design it by looking at the step response. I find that by playing around with the crossover network while observing the step response in real time, any change I make is immediately available. When I get the step response right, everything else goes along. It's implicit. It goes along for the ride.
I'd convert to a good quality DSP active crossover (which leaves behind Behringer, the bottom-end dbx Driverack, and the miniDSP 2x4) and spend an afternoon with REW or similar measurement application taking upsweeps, paying particular attention to the step response after you manually zero the time offset for each sweep (i.e., down to less than a microsecond). REW's EQ facility will significantly reduce the time needed to dial it in.

Dunlavy really didn't have access to these tools by the time they came into widespread use and were economically viable. By the early 2000s, he was reportedly beginning to suffer the effects of Alzheimer's disorder, even though he was reportedly working on a DSP-crossed loudspeaker follow-on to the SC-VI.

Chris
  Reply With Quote
Old 24th December 2018, 12:00 PM   #10
Old'n'Cranky is offline Old'n'Cranky  Australia
diyAudio Member
 
Join Date: Aug 2009
Quote:
Originally Posted by wesayso View Post
Is the balance off? Dunlavy sure new what he was doing, I wouldn't claim to be able to do better. The changed out tweeter might have upset things though.
This is pretty much a unique speaker with a clear vision, it would be a shame to mess it up. Just read the post from Cask05 above.


Please read the paper by John Dunlavy to get what he was going for. I'll send you a link trough PM. There's also lots of info including interviews on Stereophile.
Dunlavy Audio Laboratories SC-IV loudspeaker | Stereophile.com

Dunlavy Audio Labs Signature SC-VI loudspeaker | Stereophile.com

Must read interview with John Dunlavy

I was originally led to believe by the (new) owner that the tweeter had been changed.
Now I have them here, I can say they have not been changed.
These speakers are factory original.

Thanks for the links, I have read a fair bit on these already, but will read your links.

PM replied to


Quote:
Originally Posted by Cask05 View Post
A quote from Mr. Dunlavy from that last linked Stereophile article:

I'd convert to a good quality DSP active crossover (which leaves behind Behringer, the bottom-end dbx Driverack, and the miniDSP 2x4) and spend an afternoon with REW or similar measurement application taking upsweeps, paying particular attention to the step response after you manually zero the time offset for each sweep (i.e., down to less than a microsecond). REW's EQ facility will significantly reduce the time needed to dial it in.

Dunlavy really didn't have access to these tools by the time they came into widespread use and were economically viable. By the early 2000s, he was reportedly beginning to suffer the effects of Alzheimer's disorder, even though he was reportedly working on a DSP-crossed loudspeaker follow-on to the SC-VI.

Chris
The owner is not tech savy (not in this area anyway). And the expense of going active would be a huge no from him.

These speakers really do a lot very right.
Far more than almost any other speaker I've heard.

I have zero plans on changing any component values.
Just updating the solen (shudders) parts for more modern, better manufactured items.

And yes I know some out there are reading my posts groaning and yelling at the screen

Thats ok. I do the same with some of the posts I read from others

I didn't know John (RIP) suffered Alzheimer's.
My next door neighbour had extremely rapid onset Alzheimer's so I know just terrible this is.
  Reply With Quote

Reply


Dunlavy SC IV schematics ?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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Dunlavy IV Question maxpou Multi-Way 0 9th July 2010 08:11 PM
Help with dunlavy SM1 crossover ebenai Multi-Way 12 27th December 2008 12:21 AM
Crossover Schematics Dunlavy SC-V dazzdax Multi-Way 0 29th October 2006 01:00 AM
dunlavy sc-1 maxpou Multi-Way 4 2nd May 2006 11:23 PM
Dunlavy out of business? eLarson Everything Else 0 10th November 2002 01:16 PM


New To Site? Need Help?

All times are GMT. The time now is 03:18 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki