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

KEF Q500 new crossover
KEF Q500 new crossover
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 5th April 2019, 01:18 AM   #1
wtnsmk is offline wtnsmk  United Kingdom
diyAudio Member
 
Join Date: Apr 2019
Location: London
Default KEF Q500 new crossover

I've recently upgraded my Cambridge Audio CP1 phono with new caps and op-amps, and I'm so happy with the results, so nothing can stop me now haha...



So I own a pair of KEF Q500 with Cambridge CXA60. Really killer combo IMO.

As I was planning to change the caps to better ones, so I checked online, and everyone is saying that crossover is terrible design.

I tried to find all the content on the internet, but I only find two specifically with Q500.

What I'm planning to do:
  • Change the resistors to Mils
  • Upgrade the film cap to Mundorf MKP or Silver/Oil (this one is crazy expensive, so I'm not sure I will pick this one)
  • Upgrade the big 1000uF cap to Mundorf Ecap or Mlytic? Which one should I chose? Same price
  • Changing the inductors. And this is the part where I'm stuck. What gauge should I use? And what wire? I was checking the Jentzen air cores.

Also Bruce W. mentioned in a comment under a the absolute sound Q500 test the Zobel network. I have no idea how to implement this hahaha

Here is a picture with the two sides of the crossover:
q500 crossover - Album on Imgur

Could anyone help me with this? Is there anyone who already did something similar?
  Reply With Quote
Old 5th April 2019, 02:26 AM   #2
Sonce is offline Sonce  Macedonia
diyAudio Member
 
Join Date: Jan 2014
Location: Macedonia
Quote:
Originally Posted by wtnsmk View Post
everyone is saying that crossover is terrible design.

What I'm planning to do:
  • Change the resistors to Mils
  • Upgrade the film cap to Mundorf MKP or Silver/Oil (this one is crazy expensive, so I'm not sure I will pick this one)
  • Upgrade the big 1000uF cap to Mundorf Ecap or Mlytic? Which one should I chose? Same price
  • Changing the inductors.
If the crossover is terrible design, than do not "upgrade" it with crazy expensive components (with the same values). You will end up with crazy expensive terrible crossover.

Are you sure the crossover is terrible in design? Any measurements?
  Reply With Quote
Old 5th April 2019, 02:51 AM   #3
eriksquires is offline eriksquires  United States
diyAudio Member
 
eriksquires's Avatar
 
Join Date: May 2013
When replacing inductors you should take care to match the DCR of the originals. Don't go willy-nilly lowering them.



For shunt caps, some crossovers can be extra sensitive. Measure ESR and compensate by altering any series resistors.



But yes, the best approach is to analyze the crossover itself first. Make sure you want to replace those parts to begin with, or whether you find opportunities for improvement.
__________________
All of my successes and failures can be explained by my attempts at getting a girlfriend. All of them.
  Reply With Quote
Old 5th April 2019, 04:23 AM   #4
DickHertz is offline DickHertz  United States
diyAudio Member
 
Join Date: Feb 2006
Don't change inductors. Caps and resistors are OK, although you might not hear any difference at all. And if you do hear a difference, is it better than the stock crossover?
  Reply With Quote
Old 5th April 2019, 08:34 AM   #5
maty tinman is offline maty tinman  Spain
diyAudio Member
 
maty tinman's Avatar
 
Join Date: Apr 2012
Location: Tarragona (Spain)
Your picture:

Click the image to open in full size.


But KEF Q500 Crossover upgrade

Click the image to open in full size.
__________________
"Comment is free, but facts are sacred" - C. P. Scott *** 40 years of the Spanish Constitution, My musical celebration
  Reply With Quote
Old 5th April 2019, 08:35 AM   #6
maty tinman is offline maty tinman  Spain
diyAudio Member
 
maty tinman's Avatar
 
Join Date: Apr 2012
Location: Tarragona (Spain)
KEF Q900 crossover

Click the image to open in full size.
__________________
"Comment is free, but facts are sacred" - C. P. Scott *** 40 years of the Spanish Constitution, My musical celebration
  Reply With Quote
Old 5th April 2019, 10:31 AM   #7
wtnsmk is offline wtnsmk  United Kingdom
diyAudio Member
 
Join Date: Apr 2019
Location: London
I made a diagram of the stock crossover: Click the image to open in full size.
  Reply With Quote
Old 5th April 2019, 10:33 AM   #8
wtnsmk is offline wtnsmk  United Kingdom
diyAudio Member
 
Join Date: Apr 2019
Location: London
Quote:
Originally Posted by Sonce View Post
If the crossover is terrible design, than do not "upgrade" it with crazy expensive components (with the same values). You will end up with crazy expensive terrible crossover.

Are you sure the crossover is terrible in design? Any measurements?
I'm not sure in the design, this is the first time when I'm actually trying to understand any crossover. As I said, this is what people say. but I got your point.
  Reply With Quote
Old 5th April 2019, 10:54 AM   #9
Zvu is offline Zvu  Serbia
diyAudio Member
 
Zvu's Avatar
 
Join Date: Jan 2009
Location: Belgrade
It's better to leave it as is if you don't know what you are doing. Two way crossover is hard enough to get right, let alone three way - that i'd recommend here. 2.5 way is kinda compromised more than it should since the cone of midwoofer is a waveguide for the tweeter. When used as midwoofer, cone moves +/-2mm at normal listening levels so effectively the waveguide jumps around the tweeter and that's not ideal by any standards.

I'd recommend making it a three way with crossover points arround 150Hz and 2kHz. I have measurements of that concentric driver used in Q500 and a crossover at 2kHz yields very good frequency response and directivity caracteristics. Woofer should be measured for ts. It seems to me that it has rather large Qts so they've used large capacitor in series to controll the bass bump.

I wouldn't do any mods prior to:

1.Measuring raw driver responses in factory cabinets at least 2.2m high in air outdoors 0-90 degrees.
2.Measuring woofer TS parameters.
3.Deriving parameters of passive radiators used so i can model the response.

Then and only then, simulated response will match measured one.

Last edited by Zvu; 5th April 2019 at 10:57 AM.
  Reply With Quote
Old 5th April 2019, 11:30 AM   #10
chris661 is online now chris661  United Kingdom
diyAudio Member
 
chris661's Avatar
 
Join Date: Feb 2008
Location: Sheffield
It doesn't look like the stock crossover is up to much. 1000uF in series with a PR alignment is crazy to me.

If you're near Sheffield, gimme a shout and we can do this properly, starting with some good measurements.

Chris
__________________
My work: www.grimshawaudio.com
  Reply With Quote

Reply


KEF Q500 new crossoverHide 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
Pulseaudio Crossover Rack - multi-way crossover design & implementation with linux Tfive PC Based 267 8th May 2019 05:14 PM
KEF Q500 Crossover upgrade rdsu Multi-Way 14 12th October 2017 03:39 PM
Do i need analog active Crossover or Digital Crossover for DIY home theatre speakers? dipankar862 Multi-Way 43 16th March 2017 05:55 AM
Can you use a digital active crossover to design a passive analog crossover ? RickDangerous Digital Line Level 27 1st April 2013 05:59 AM
Can you hear the crossover point of a speaker with a well-designed crossover? 454Casull Multi-Way 11 2nd April 2004 05:48 AM


New To Site? Need Help?

All times are GMT. The time now is 01:00 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki