weiss

Simple High Pass and Low Pass Filter unit for mastering
« on: February 05, 2019, 02:22:41 PM »
Hey guys,

i was wondering if anyone ever built like a hpf/lpf filter unit (like used in the bax eq for example) without any other filters involved. Preferably with switchable slope, 24/48db 6/12db (no idea if that's possible)?

Is it a complex task to build?

thanks for the input
« Last Edit: February 05, 2019, 06:38:06 PM by weiss »


john12ax7

Re: Simple High Pass and Low Pass Filter unit for mastering
« Reply #1 on: February 05, 2019, 06:13:25 PM »
Is a super high slope that useful? Seems there would be more phase issues.

weiss

Re: Simple High Pass and Low Pass Filter unit for mastering
« Reply #2 on: February 05, 2019, 06:36:29 PM »
Is a super high slope that useful? Seems there would be more phase issues.

you are right, after reading some more, i gotta correct myself. probably 6 or 12 db is enough  ::)
Now i came across the harrison ford filters. seems to be most usable for what i had planned.
other ideas/experiences?

thanks  :)

john12ax7

Re: Simple High Pass and Low Pass Filter unit for mastering
« Reply #3 on: February 05, 2019, 06:48:02 PM »
The harrison would do the job. Although for mastering you probably want stepped switches?  So you could go even simpler, passive RC networks  with a buffer.

weiss

Re: Simple High Pass and Low Pass Filter unit for mastering
« Reply #4 on: February 05, 2019, 06:58:13 PM »
The harrison would do the job. Although for mastering you probably want stepped switches?  So you could go even simpler, passive RC networks  with a buffer.

indeed i need switches only.
you mean something like that? how would i realize different frequencies?

LP


HP

john12ax7

Re: Simple High Pass and Low Pass Filter unit for mastering
« Reply #5 on: February 05, 2019, 08:05:53 PM »
Those are the classic Sallen Key filters that the harrsion and others are based on. If you look at schematics usually the Cs are fixed and R3 and R4 replaced by a dual pot which then varies the frequency. So just use a switch to select appropriate R values instead of a pot.

Have you seen these? Maybe it could be modded for switched operation?
https://groupdiy.com/index.php?topic=68367.0

weiss

Re: Simple High Pass and Low Pass Filter unit for mastering
« Reply #6 on: March 13, 2019, 05:09:21 PM »
Those are the classic Sallen Key filters that the harrsion and others are based on. If you look at schematics usually the Cs are fixed and R3 and R4 replaced by a dual pot which then varies the frequency. So just use a switch to select appropriate R values instead of a pot.

Have you seen these? Maybe it could be modded for switched operation?
https://groupdiy.com/index.php?topic=68367.0

thank you! no, i haven't seen these, looking very nice!

Rocinante

Re: Simple High Pass and Low Pass Filter unit for mastering
« Reply #7 on: Today at 02:20:10 PM »
I did the Harrison's with stepped switches. I never used them so sold them but I don't do nearly as much mastering as others
If there's a harder way to do this, I haven't found it yet.

weiss

Re: Simple High Pass and Low Pass Filter unit for mastering
« Reply #8 on: Today at 06:56:45 PM »
I did the Harrison's with stepped switches. I never used them so sold them but I don't do nearly as much mastering as others

nice. simple lorlins? do you remember the values used?

 

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