Cutting low frequency

Dobs · 10th May 2010, 08:53 PM

I need help to cut 50Hz frequency and below on my 8ohms fullrange. I want a very simple way.

Thanks

richie00boy · 10th May 2010, 09:07 PM

Back-to-back connected 1000uF electrolytic caps in each positive speaker lead.

Dobs · 10th May 2010, 09:15 PM

I just put a 1000uF capacitor on the + lead on each channel, that right?

Glowbug · 10th May 2010, 09:34 PM

Could do it line-level, as well...

Parts-Express.com:FMOD Crossover Pair 50 Hz High Pass | rca PA ir high pass fmods fmod f mod Crossovers air active crossover

Dobs · 10th May 2010, 09:55 PM

How is this calculated?

Saturnus · 11th May 2010, 06:12 AM

Quote:

Originally Posted by Dobs

How is this calculated?

Like a normal filter. You just use the input impedance instead of the speaker impedance.

It's also called a PLLXO.

planet10 · 11th May 2010, 06:15 AM

Quote:

Originally Posted by Saturnus

PLLXO

Passive Line-Level Crossover

dave

kipman725 · 11th May 2010, 10:31 AM

Quote:

Originally Posted by Dobs

How is this calculated?

by much maths! see attached. The formula at the end is probobly the only bit of interest but I felt like showing why this works. Disadvantage of first order filters are there very slow roll off (-6dB/octave).

higher order filters must be constructed out of inductors and capacitors to be practical or be at line level.

freddi · 11th May 2010, 12:42 PM

a capacitor at speaker level can increase excursion though interaction with impedance peak(s) - - -do it line level

Dobs · 11th May 2010, 02:01 PM

Quote:

Originally Posted by freddi

a capacitor at speaker level can increase excursion though interaction with impedance peak(s) - - -do it line level

I cant go that way, I have to go speaker level.

Can you explain that interaction simply?

10th May 2010, 08:53 PM	#1
Dobs diyAudio Member Join Date: Jul 2008	Cutting low frequency I need help to cut 50Hz frequency and below on my 8ohms fullrange. I want a very simple way. Thanks

10th May 2010, 09:07 PM	#2
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	Back-to-back connected 1000uF electrolytic caps in each positive speaker lead. __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

10th May 2010, 09:34 PM	#4
Glowbug diyAudio Member Join Date: Feb 2006 Location: Hillsborough, NC/McLean, VA	Could do it line-level, as well... Parts-Express.com:FMOD Crossover Pair 50 Hz High Pass \| rca PA ir high pass fmods fmod f mod Crossovers air active crossover __________________ Jim J.

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10th May 2010, 09:15 PM	#3
Dobs diyAudio Member Join Date: Jul 2008	I just put a 1000uF capacitor on the + lead on each channel, that right?

10th May 2010, 09:55 PM	#5
Dobs diyAudio Member Join Date: Jul 2008	How is this calculated?

11th May 2010, 12:42 PM	#9
freddi diyAudio Member Join Date: Aug 2005	a capacitor at speaker level can increase excursion though interaction with impedance peak(s) - - -do it line level

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