Is making an XO on a PCB a bad thing? - 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 17th November 2004, 11:42 AM   #1
diyAudio Member
 
Join Date: Mar 2004
Location: At the output stage
Send a message via Yahoo to mr_push_pull
Default Is making an XO on a PCB a bad thing?

I had the idea of making the XO on a PCB and I read that some recommend against that. I also left big areas of copper (I etched only a few millimeters around the traces because I had little etchant left and I was too lazy to go buy some) and I'm wondering if the capacitance made from the big copper areas will hurt the sound. Should I bother to redo the XO's?
__________________
we all love a good ol' stereotype until it's against us
  Reply With Quote
Old 17th November 2004, 12:47 PM   #2
Did it Himself
diyAudio Member
 
richie00boy's Avatar
 
Join Date: Nov 2003
Location: Gloucestershire, England, UK
I'm a big fan of PCBs for everything. The capacitances from your board will be absolutely negligible in a speaker level crossover.
  Reply With Quote
Old 17th November 2004, 12:49 PM   #3
Colin is offline Colin  United Kingdom
diyAudio Member
 
Join Date: Aug 2003
There's a feeling that PCBs are an unnecessary complication and may even make things worse - by hard wiring you can wire the components directly together (reducing the solder connections and intervening pcb tracks), it's easier to fix them to the board ina more robust fashion and you can space the components farther apart to reduce interactions. I remember Russ Andrews telling me of some experiments he did when working as a consultant - they took the x-over components off the pcb, spaced them farther apart and reconnected them - then fell about laughing at the size of improvement it made.

Colin
  Reply With Quote
Old 17th November 2004, 12:51 PM   #4
diyAudio Member
 
Join Date: Mar 2004
Location: At the output stage
Send a message via Yahoo to mr_push_pull
Quote:
Originally posted by richie00boy
I'm a big fan of PCBs for everything. The capacitances from your board will be absolutely negligible in a speaker level crossover.
My question is kinda stupid and worrying about this is probably overkill, but it will help me sleep better tonight
__________________
we all love a good ol' stereotype until it's against us
  Reply With Quote
Old 17th November 2004, 01:40 PM   #5
diyAudio Member
 
john k...'s Avatar
 
Join Date: Aug 2004
Location: US
The major thing that affects crossover perfromance is inductor spacing and orentation. I f you want to use a small PCB then mout the inductors off the board and run reasonable sized lead to them.
__________________
John k.... Music and Design NaO Dipole Loudspeakers.
  Reply With Quote
Old 17th November 2004, 01:44 PM   #6
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
If the inductors are pretty near each other you have to orient them 90 degrees twisted otherwise you will get inductive coupling and mutual inductance.
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy. Still time for signing up.
  Reply With Quote
Old 17th November 2004, 02:17 PM   #7
diyAudio Member
 
Join Date: Mar 2004
Location: At the output stage
Send a message via Yahoo to mr_push_pull
Quote:
Originally posted by peranders
If the inductors are pretty near each other you have to orient them 90 degrees twisted otherwise you will get inductive coupling and mutual inductance.
I have a 1mH coil of approx 5.5cm diameter and a 0.22mH one of approx 3cm diameter. They are placed maybe 3 cm away from each other. I gues this isn't enough?
__________________
we all love a good ol' stereotype until it's against us
  Reply With Quote
Old 17th November 2004, 03:44 PM   #8
diyAudio Member
 
Join Date: Sep 2004
Location: Central California
A pc board will work just fine. Just make sure your trace width can handle the expected current. Close spacing if inductors is fine if they are in the same branch. Even if they are in different branches, unless you expect large currents, they dont need to be placed very far apart. If you have a scope, look at the output of the mid or high section while feeding a low frequency signal to the bass section. How much energy do you see?
  Reply With Quote
Old 18th November 2004, 07:43 AM   #9
diyAudio Member
 
Join Date: Mar 2004
Location: At the output stage
Send a message via Yahoo to mr_push_pull
Quote:
Originally posted by Hornlover
A pc board will work just fine. Just make sure your trace width can handle the expected current. Close spacing if inductors is fine if they are in the same branch. Even if they are in different branches, unless you expect large currents, they dont need to be placed very far apart. If you have a scope, look at the output of the mid or high section while feeding a low frequency signal to the bass section. How much energy do you see?
The traces are about 4-5 mm wide and I covered them with solder alloy. I think I'll hardly get into the region where current is a concern.
__________________
we all love a good ol' stereotype until it's against us
  Reply With Quote
Old 18th November 2004, 08:20 PM   #10
MarkMcK is offline MarkMcK  United States
diyAudio Member
 
Join Date: Aug 2003
Location: Ohio
Besides capacitance, you can worry about eddy currents. Dahlquist tried beautifully made pc boards on the DQ10 in the late 80s and had to recall them because of too many complaints of "distorted" sound. And yes, it could be measured as well as heard. Big wide traces, with lots of conductor surface area, make nice eddy current pickups.

Like everything, it is not a case of pc boards or not pc boards, but how a particular project is designed and constructed.

With all of the free fft based spectrum analyzers available it is easy to measure component interaction when prototyping board layout.


Best of luck to you,

Mark
  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
The Second best thing phn Music 11 12th November 2006 10:59 AM
The next big thing? pinkmouse Everything Else 7 15th August 2006 03:24 AM
pre-out vs rec-out ...same thing or not? roger2 Solid State 7 27th July 2006 09:57 PM
next best thing kartsmart Digital Source 5 9th November 2005 10:38 PM
The best thing... Nickolas K. Pass Labs 7 9th July 2003 09:01 PM


New To Site? Need Help?

All times are GMT. The time now is 10:42 AM.


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