Passive Notch Filter for Eminence Alpha 15As

Horizons · 24th February 2009, 11:12 PM

I am using a pair of these in an OB design and passively crossing around 900 Hz (2nd order BW) to one of Earls 15-inch WGs with compression driver.

I still hear a little coloration in the Alphas. Can anyone point me to a site or calculator as I want to try a passive notch to passively filter a pair of these (4 ohms) around 2 Khz as I think that is where the problem is.

http://www.usspeaker.com/ALPHA15-1.htm

Or should I just go 4th order passive to try to filter the 2 Khz peak?

infinia · 24th February 2009, 11:42 PM

Not sure what you have for BSC and what else you are using for open baffle correction (s/b active?) circuit wise, but painting in broad strokes...

If it were me and I wasn't going active or using a different woofer I'd use a biggish BSC inductor with notch for open baflle and another for the woofer breakup. Note the breakup is highly directional and probably gone at 45-60 deg off axis.

You could look at using an eliptical 3rd order LPF depending on the preceding inductor/filter used for the other corrections.

MisterTwister · 25th February 2009, 05:28 PM

900hz is too high for these woofers.
at this frequency FR needs to be dropped real hard

I'd do 4th+ order and notch.
it would get quite expensive with passive components.
calculators won't work. the can give you general idea what values to look for. but for precise crossover drivers must be measured.

mcmahon48 · 27th February 2009, 04:22 AM

http://www.diyaudioandvideo.com/Calc...ParallelNotch/

24th February 2009, 11:12 PM	#1
Horizons diyAudio Member Join Date: Sep 2004 Location: Nevada	Passive Notch Filter for Eminence Alpha 15As I am using a pair of these in an OB design and passively crossing around 900 Hz (2nd order BW) to one of Earls 15-inch WGs with compression driver. I still hear a little coloration in the Alphas. Can anyone point me to a site or calculator as I want to try a passive notch to passively filter a pair of these (4 ohms) around 2 Khz as I think that is where the problem is. http://www.usspeaker.com/ALPHA15-1.htm Or should I just go 4th order passive to try to filter the 2 Khz peak?

24th February 2009, 11:42 PM	#2
infinia diyAudio Member Join Date: May 2005 Location: Californication	Not sure what you have for BSC and what else you are using for open baffle correction (s/b active?) circuit wise, but painting in broad strokes... If it were me and I wasn't going active or using a different woofer I'd use a biggish BSC inductor with notch for open baflle and another for the woofer breakup. Note the breakup is highly directional and probably gone at 45-60 deg off axis. You could look at using an eliptical 3rd order LPF depending on the preceding inductor/filter used for the other corrections. __________________ like four million tons of hydrogen exploding on the sun like the whisper of the termites building castles in the dust

27th February 2009, 04:22 AM	#4
mcmahon48 diyAudio Member Join Date: Aug 2008	here is a website http://www.diyaudioandvideo.com/Calc...ParallelNotch/

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25th February 2009, 05:28 PM	#3
MisterTwister diyAudio Member Join Date: Feb 2006 Location: usa Blog Entries: 1	900hz is too high for these woofers. at this frequency FR needs to be dropped real hard I'd do 4th+ order and notch. it would get quite expensive with passive components. calculators won't work. the can give you general idea what values to look for. but for precise crossover drivers must be measured.

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