passive crossovers.... - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

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 20th August 2007, 05:05 PM   #1
stuman is offline stuman  United Kingdom
diyAudio Member
 
Join Date: Nov 2004
Location: Fareham
Default passive crossovers....

on payday this month i will be buying a subwoofer for my bedroom audio, the problem is the small speakers that i use are in full range at the moment and when i put the subwoofer in would like to have a bass pass filter on them at about 50hz where they start to drop off naturally so that when pushed to high SPL's i dont get the port chuffing noises, i could always bung the bassport on the back but not sure weather the response curve would be as good as it is with.

so what im basically asking is are there any good designs out there for a passive 50hz bass filter?
  Reply With Quote
Old 20th August 2007, 05:15 PM   #2
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: Near Vancouver
A 50 Hz passive XO will be very expensive. Consider using an active filter. In fact, you can often buy a plate amp with a built in XO for little more than the components needed for a passive 50 Hz.
__________________
Next stop: Margaritaville
Some of Cal's stuff | Cal Weldon Consulting
  Reply With Quote
Old 21st August 2007, 02:10 AM   #3
Banned
 
Join Date: Apr 2005
Location: Stockholm
Hi,
I would just place a capacitor at the input of the poweramp
  Reply With Quote
Old 21st August 2007, 07:51 AM   #4
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally posted by Lumba Ogir
Hi,
I would just place a capacitor at the input of the poweramp
This is the way to go. Here is a web page that will help you figure out how big the cap needs to be (ise the input impedance of your amp as R2 in the 1st order high pass filter.

http://t-linespeakers.org/tech/filters/passiveHLxo.html

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 21st August 2007, 09:25 AM   #5
bastek is offline bastek  United States
diyAudio Member
 
Join Date: Dec 2005
Location: NY
I use a 150microF electrolytic in series with the woofer input on the speaker. If your speaker only has 2 posts, you can add a 10microF polypropylene cap in parallel. My 2 way bookself has a 5.25" mid-woofer.
  Reply With Quote
Old 21st August 2007, 10:27 AM   #6
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally posted by bastek
I use a 150microF electrolytic in series with the woofer input on the speaker. If your speaker only has 2 posts, you can add a 10microF polypropylene cap in parallel. My 2 way bookself has a 5.25" mid-woofer.
An elco after the amp will not sound anywhere near as good as a poly before the amp... also to get his desired 50 Hz he'd need 400 uF if the speaker was a flat 8 ohms, but a speaker near its cut off is far from flat.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 21st August 2007, 03:00 PM   #7
stuman is offline stuman  United Kingdom
diyAudio Member
 
Join Date: Nov 2004
Location: Fareham
sorry, i should have posted some more info.

the sound is going to be sent to my amp which has a dedicated line out for subwoofer which i am planning on using thats all fine however i would like to filter the the speakers on from the standard binding posts and was wandering about decent crossovers? i can spend about 200 for the pair? any ideas?
  Reply With Quote
Old 21st August 2007, 06:31 PM   #8
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally posted by stuman
the sound is going to be sent to my amp which has a dedicated line out for subwoofer which i am planning on using thats all fine however i would like to filter the the speakers on from the standard binding posts and was wandering about decent crossovers? i can spend about 200 for the pair? any ideas?
What kind of speaker are your satelittes.

A passive XO on any speaker this low and this close to its cutoff is a nightmare and will likely be a waste of effort. You can't get at the power amp separately?

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 22nd August 2007, 11:11 PM   #9
diyAudio Member
 
Join Date: Aug 2007
sorry to take the poster over put i cant post in the main room
  Reply With Quote
Old 22nd August 2007, 11:34 PM   #10
diyAudio Member
 
Join Date: May 2003
Location: Townsville, Australia
Send a message via ICQ to phreeky82
So you just wanna high-pass the satellites using a passive x-over? Wouldn't the amp/system be doing this for you actively? If not (odd), you could just try a cap in series with the satellites but it may not be steep enough depending on the x-over freq.

As stated, a passive x-over at such a low freq is a pain in the a*se (but at least its a high-pass and not a low-pass!!!).
  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
PE Dayton passive crossovers madpoet Multi-Way 1 3rd June 2005 04:02 PM
why do we bother with passive crossovers? paulspencer Multi-Way 70 13th September 2004 08:06 AM
dB loss by using passive crossovers? Active vs Passive and 1st vs 4th order Hybrid fourdoor Multi-Way 3 11th July 2004 10:16 PM
Some basics abt passive crossovers. rakeshln Multi-Way 6 31st May 2004 12:55 PM
Solder for passive crossovers. JoeBob Multi-Way 8 31st December 2001 05:28 PM


New To Site? Need Help?

All times are GMT. The time now is 12:39 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