Active filter for subwoofer

Buzzy · 28th November 2008, 03:05 AM

I would like to build an active filter for my vented subwoofer. Would Rod Elliot project 71 be suitable for this purpose ? http://sound.westhost.com/project71.htm

There are many circuits shown on the page. Is figure 4 the circuit i should be building ? I dunno if it is complete or if some stuff is missing.

TheSeekerr · 28th November 2008, 04:22 AM

What do you want the filter to do? The circuit you linked to is typically used to extend bass response below resonance in a sealed box - it would be useful, for example, if you chose to seal the port on your current sub and then wanted to reclaim bass extension.

I don't think that's what you're trying to do. Perhaps you were looking for a rumble filter? http://sound.westhost.com/project99.htm

Or maybe you're after an active crossover? http://sound.westhost.com/project09.htm

Or perhaps you were after a graphic subwoofer equaliser? http://sound.westhost.com/project84.htm

Please elaborate on what you're trying to achieve.

Buzzy · 28th November 2008, 09:39 AM

oops sry. What i want is to cutoff the low frequencies to save my sub from over-excursion.

Btw is it ok to supply opamp with just +12 and -12V dc instead of the +15 -15V ?

AndrewT · 28th November 2008, 10:10 AM

look up sixth order alignment.
It adds a little bit of equalisation and a 12dB/octave high pass filter to a vented enclosure.
However the enclosure/driver needs to be designed in conjunction with the filter.

BWRX · 28th November 2008, 11:41 AM

Quote:

Originally posted by Buzzy
Btw is it ok to supply opamp with just +12 and -12V dc instead of the +15 -15V ?

If you're using TL072 op amps that will be perfectly fine.

Buzzy · 30th November 2008, 03:20 AM

Quote:

Originally posted by AndrewT
look up sixth order alignment.
It adds a little bit of equalisation and a 12dB/octave high pass filter to a vented enclosure.
However the enclosure/driver needs to be designed in conjunction with the filter.

Thanks for all the replies. AndrewT I don't need any equalisation in the active filter as i have a separate EQ. All i want is just to cut off freq below 16Hz so that i do not go over the excursion limit. Should i be looking at project 9 or project 99 on Rod Elliot's page ?

BWRX · 30th November 2008, 03:48 AM

The one you want is Project99 - the rumble filter.

28th November 2008, 03:05 AM	#1
Buzzy diyAudio Member Join Date: Apr 2007	Active filter for subwoofer I would like to build an active filter for my vented subwoofer. Would Rod Elliot project 71 be suitable for this purpose ? http://sound.westhost.com/project71.htm There are many circuits shown on the page. Is figure 4 the circuit i should be building ? I dunno if it is complete or if some stuff is missing.

30th November 2008, 03:48 AM	#7
BWRX diyAudio Moderator Emeritus Join Date: Jan 2005 Location: Pennsylvania	The one you want is Project99 - the rumble filter. __________________ Brian

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
active filter from rod elliot and sub filter questions	wuffer	Parts	0	2nd October 2005 01:12 PM
Active Filter	ChevS-10	Solid State	4	24th June 2005 05:35 PM
my active filter	merlinx76	Chip Amps	34	23rd February 2005 05:12 PM
subwoofer bass extension active filter?	capslock	Subwoofers	8	12th September 2002 05:05 PM
active filter	janey	Solid State	2	7th September 2001 09:30 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	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

28th November 2008, 04:22 AM	#2
TheSeekerr diyAudio Member Join Date: Jan 2008	What do you want the filter to do? The circuit you linked to is typically used to extend bass response below resonance in a sealed box - it would be useful, for example, if you chose to seal the port on your current sub and then wanted to reclaim bass extension. I don't think that's what you're trying to do. Perhaps you were looking for a rumble filter? http://sound.westhost.com/project99.htm Or maybe you're after an active crossover? http://sound.westhost.com/project09.htm Or perhaps you were after a graphic subwoofer equaliser? http://sound.westhost.com/project84.htm Please elaborate on what you're trying to achieve.

28th November 2008, 09:39 AM	#3
Buzzy diyAudio Member Join Date: Apr 2007	oops sry. What i want is to cutoff the low frequencies to save my sub from over-excursion. Btw is it ok to supply opamp with just +12 and -12V dc instead of the +15 -15V ?

28th November 2008, 10:10 AM	#4
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	look up sixth order alignment. It adds a little bit of equalisation and a 12dB/octave high pass filter to a vented enclosure. However the enclosure/driver needs to be designed in conjunction with the filter.