1. Home
  2. tech-talk
  3. 198076-2308

High pass filter

My goal is reduce a vertical axial mode at 60Hz produced from my main speakers.  A JL CR1 did the job but produced too much distortion. I have looked at passive and active line-level crossover and filter options, including DEQX. I am interested in an do-it-myself capacitor option like the one on GR Research website but 6db/octave is too shallow. I need a second order at least. Has anyone made a passive high pass filter second order or higher? I believe it is two capacitors in series with the first one ten times the value as the second. My amp is 30Kohm input impedance. I do not if a resistor is necessary. As I type this I have a sense I am going down the wrong rabbit hole. The relatively low cost and ability to alter it is compelling, though. Thanks for any help. 

ohlala
yogiboy's avatar
yogiboy
6,181 posts
 

How about this? I used this years ago with great results!

https://hsuresearch.com/collections/accessories/products/high-pass-filter

knotscott's avatar
knotscott
1,383 posts
 

I know you want a steeper slope, but have you given a first order inline high pass a try?  It's much simpler. I used a silver mica cap, and it works well and sounds wonderful for my application.  

erik_squires
17,537 posts
 

mode at 60Hz

Well the correct answer is a parametric EQ honestly. Even better with bass traps in the right location.  A single cap HP filter is an excellent idea when you are bi-amping but here it's going to just make your system sound too lean.

My suggestion is get an inexpensive miniDSP and try it.  Or if you stream with Roon it has DSP filtering built in. 

If you are just dying to solder something try an LC in series, I think 0.7mH and 100uF could work, I may have done the math wrong, with a variable resistor around 30k-100K pot around the whole thing so you can adjust the dip depth.  You wont get what you really need which is variable filter width but hey, worth playing with. 

deep_333
2,420 posts
 

A approximately 9 ft ceiling would produce a strong 60hz null at the 4.5 ft height.

Do you have a sub?

Put a sub on the floor by the front wall.

Get a 2nd sub, a in-wall sub like this sub from SVS or similar and put it on your ceiling by the back wall.

https://www.crutchfield.com/p_9463KIWDSS/SVS-3000-In-wall-Dual-Subwoofer-System.html

With correct phase adjustment, that null will be gone. You can't peq your way out of nulls. 

You will get rid of heightwise modes, lengthwise modes and widthwise modes in  your room by correctly placing just that one sub on the floor and one sub on the ceiling. 

@ohlala  wrote

My goal is reduce a vertical axial mode at 60Hz produced from my main speakers.  

 

More to discover