Sub crossover help - 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 6th January 2007, 03:02 AM   #1
diyAudio Member
 
Join Date: Mar 2006
Location: Canada
Default Sub crossover help

I'm really new to the DIY audio stuff and well about a year ago i got a sub(Just the sub no box or anything) for my birthday. i designed a box for it but i still need to make a crossover so i don't mess it up. I have my audio coming from my computer to my one receiver and from the sub out to my other receiver which already controls my other 12" sub(was pre built with crossover). What i need is for someone to design a crossover for my new sub so i can get it going. Any help would be appreciated. Thanks
  Reply With Quote
Old 7th January 2007, 08:58 PM   #2
mikee55 is offline mikee55  United Kingdom
diyAudio Member
 
mikee55's Avatar
 
Join Date: Dec 2005
Location: West Howe
Default Have a Google!!

Look for Rod Elliott or rather Elliott Sound Products

Perhaps why no one has bothered to reply.Google your question then come here.

Cheers mikee55
__________________
If it don't work, I'll fix it in the mix! Or visit http://lsdp.proboards.com/index.cgi
  Reply With Quote
Old 7th January 2007, 11:48 PM   #3
diyAudio Member
 
Join Date: Mar 2006
Location: Canada
K i found/made the plans for the cross over but now i need to know a good place to order or get capacitors and Inductors. Any ideas??
  Reply With Quote
Old 8th January 2007, 01:54 AM   #4
lndm is offline lndm  Australia
diyAudio Member
 
Join Date: Mar 2006
Location: nsw
Default Re: Sub crossover help

Quote:
Originally posted by Nathan1k9
from the sub out
Does this output put out only the bass? If so, a crossover may not be strictly necessary and might actually be less good.
  Reply With Quote
Old 8th January 2007, 08:14 AM   #5
diyAudio Member
 
Join Date: Mar 2006
Location: Canada
All it really does is lower the highs. cause i have hooked up the sub to it before and you can hear pretty much all the noise, plus some cracks and pops from the higher frequencies.
  Reply With Quote
Old 8th January 2007, 10:17 AM   #6
lndm is offline lndm  Australia
diyAudio Member
 
Join Date: Mar 2006
Location: nsw
It sounds possible that the lowering of the highs means a first order rolloff at some frequency. What you could do is decide on an appropriate frequency and apply one more order of rolloff by way of a crossover on the woofer.

This is typically done with one capacitor, one resistor and one inductor. The resistor and capacitor flatten out the woofers impedance and the inductor does the rolloff.

If you had an impedance plot, that would be most helpful, otherwise any information you can give including your desired frequency. If you're not sure of the frequency to choose, post a bit about your system and setup.
  Reply With Quote
Old 9th January 2007, 12:17 AM   #7
diyAudio Member
 
Join Date: Mar 2006
Location: Canada
Well the Frequency i would like it to start to roll off would be about 90-100 Hz. The Sub is 8 ohms.


Quote:
The resistor and capacitor flatten out the woofers impedance and the inductor does the rolloff.
How come for all the things I have done to try and make a plan for the cross over it's only shown Capacitors and Inductors?? I have read a little about flattening the impedance but it's never really said how.
  Reply With Quote
Old 9th January 2007, 04:30 AM   #8
lndm is offline lndm  Australia
diyAudio Member
 
Join Date: Mar 2006
Location: nsw
Learning about crossovers can become steep if too much is mentioned at once and this might be one possible reason that introductions don't go this far. Basically, filter theory is introduced in it's fundamental form - working into a resistor, but a speaker does not strictly behave like a resistor.

A typical speaker's impedance rises from around 100-200Hz or so and up. This will likely be the main area of interest in your case. An inductor's impedance rises with frequency too, and if the speaker and inductor both are rising, the net effect will be somewhat nullified.

If you try to cross over too low, you'll need to consider the speakers rise in impedance around it's resonance. Better to cross over more than three times the resonance frequency and don't worry about this at this point.

The capacitor is typically between a few uF and several tens of uF depending on the speaker. The resistor should be around 1.25 times the DC resistance of the voice coil measured with a multimeter (probably around an 8 ohm resistor in your case). Your inductor might need to be in the vicinity of 10-15mH.

Take one leg of the capacitor and connect it to one terminal of the speaker. Connect the other leg to one leg of the resistor, and connect the other leg of the resistor to the other terminal of the speaker.

Connect one terminal to ground. Connect the other terminal to one leg of the inductor and the other leg to the positive output of the amp.

Hope this helps.
  Reply With Quote
Old 9th January 2007, 10:32 PM   #9
diyAudio Member
 
Join Date: Mar 2006
Location: Canada
This helps a lot. I think i'l try a couple different crossovers to see what i can come up with. All i need to know now is a good place to buy resistors, capacitors and inductors. Any good online site to order from?? I haven't been able to find many places here yet. Thanks
  Reply With Quote
Old 9th January 2007, 10:53 PM   #10
lndm is offline lndm  Australia
diyAudio Member
 
Join Date: Mar 2006
Location: nsw
I'm not from your half of the world and haven't used them, but I've noticed some Canadians mention this place http://www.partsexpress.com/webpage.cfm?WebPage_ID=31
  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
Crossover for vifa 2 way setup - how can I find out what this crossover is doing? Tino Multi-Way 11 17th May 2009 05:21 AM
Help me with a crossover. raypalmer Multi-Way 4 5th April 2009 02:48 AM
Passive crossover into active crossover hahfran Multi-Way 16 10th February 2008 07:16 PM
Crossover help please :) Tenson Multi-Way 17 15th April 2006 10:34 AM
Can you hear the crossover point of a speaker with a well-designed crossover? 454Casull Multi-Way 11 2nd April 2004 06:48 AM


New To Site? Need Help?

All times are GMT. The time now is 01:37 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