how to calculate resonance freq in H-baffle

bvan · 13th January 2009, 11:00 PM

Can anyone tell me how to work out how deep(front and back of the driver plane) I can make the sides of an H-baffle before I need to start worrying about resonances. I'll likely run the subs as high as 250hz and shelve the 24db/oct above that. Thanks

djk · 14th January 2009, 03:43 AM

http://www.audioasylum.com/forums/hu...13/139455.html

"I was expecting it to take some time to get aquainted with the way that it sounds but I knew within seconds that it was what I wanted. It's cleaner , faster and the kind of bass that usually comes from servo systems. I'm even able to drive the woofers much harder before cone break up.
My actual tuning came out to 33hz. and they sound very linear up to 400hz. Thanks "

bvan · 14th January 2009, 08:49 AM

Looks like a good design, but I'm thinking dipole subs might match better with dipole mains, having similar radiation patterns and all?

I've heard of quarter wavelength resonances, and can work out what this translated to (about a foot), but I'm not sure if it's half, quarter, eighth etc that I should be concerned about.

cheers

Rudolf · 14th January 2009, 02:58 PM

Quote:

Originally posted by bvan
I've heard of quarter wavelength resonances, and can work out what this translated to (about a foot), but I'm not sure if it's half, quarter, eighth etc that I should be concerned about.

It is the quarter wavelenght (distance from driver plane to either opening). The effective wavelenght will be a bit longer than the geometric dimension. If you shelve below that with 24 dB you don´t need to bother about the higher resonances at all.

djk · 14th January 2009, 03:53 PM

"Looks like a good design, but I'm thinking dipole subs might match better with dipole mains, having similar radiation patterns and all?"

By all means, try the dipole. The basic idea may be adapted to sealed, vented, and dipole. Mine have always been 6th oder vented.

The primary limit on HF response is the depth of the plenum, and the cavity formed by same. The back corners of the cavity can be filled with 703 fiberglass if you like. I think if you keep dimensions to a minimum and cross at 24dB that you will have no problems. I have successfully crossed 18s over at 250hz in a couple of my designs.

bvan · 14th January 2009, 10:52 PM

thanks djk

13th January 2009, 11:00 PM	#1
bvan diyAudio Member Join Date: Apr 2006	how to calculate resonance freq in H-baffle Can anyone tell me how to work out how deep(front and back of the driver plane) I can make the sides of an H-baffle before I need to start worrying about resonances. I'll likely run the subs as high as 250hz and shelve the 24db/oct above that. Thanks

14th January 2009, 03:43 AM	#2
djk diyAudio Member Join Date: Feb 2001 Location: USA	http://www.audioasylum.com/forums/hu...13/139455.html "I was expecting it to take some time to get aquainted with the way that it sounds but I knew within seconds that it was what I wanted. It's cleaner , faster and the kind of bass that usually comes from servo systems. I'm even able to drive the woofers much harder before cone break up. My actual tuning came out to 33hz. and they sound very linear up to 400hz. Thanks " __________________ Candidates for the Darwin Award should not read this author.

14th January 2009, 03:53 PM	#5
djk diyAudio Member Join Date: Feb 2001 Location: USA	"Looks like a good design, but I'm thinking dipole subs might match better with dipole mains, having similar radiation patterns and all?" By all means, try the dipole. The basic idea may be adapted to sealed, vented, and dipole. Mine have always been 6th oder vented. The primary limit on HF response is the depth of the plenum, and the cavity formed by same. The back corners of the cavity can be filled with 703 fiberglass if you like. I think if you keep dimensions to a minimum and cross at 24dB that you will have no problems. I have successfully crossed 18s over at 250hz in a couple of my designs. __________________ Candidates for the Darwin Award should not read this author.

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
Tapped Horn and Driver resonance Freq.	Bent	Subwoofers	44	17th April 2009 11:05 AM
Baffle cutoff freq for N baffle	mashaffer	Subwoofers	1	25th June 2007 05:29 PM
how to calculate resonance in dipole H-frame?	thadman	Subwoofers	4	17th April 2007 08:10 PM
How to kill a 100Hz open baffle resonance?	Katapum	Full Range	12	22nd November 2005 03:51 PM
How to calculate baffle step?	henriksommer	Multi-Way	11	7th May 2004 07:16 AM


	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

14th January 2009, 08:49 AM	#3
bvan diyAudio Member Join Date: Apr 2006	Looks like a good design, but I'm thinking dipole subs might match better with dipole mains, having similar radiation patterns and all? I've heard of quarter wavelength resonances, and can work out what this translated to (about a foot), but I'm not sure if it's half, quarter, eighth etc that I should be concerned about. cheers

14th January 2009, 10:52 PM	#6
bvan diyAudio Member Join Date: Apr 2006	thanks djk

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

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