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High Pass Filter (HPF) and Low Pass Filter (LPF) Mega Thread

If you are not pushing the extreme low or high frequencies you dont need it, most hp/lp filters act as cab sims more than anything else, i use mine to get a vintage-y tone (basically back in the day lows werent so low and highs werent so high(?lol)) so the hp/lp makes that happen, sometimes i really push the eq and drive and thats also when the hp/lp comes into play, it is not a necessity you can do without one but it sure does come in handy at a venue with bad acoustics etc.
 
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I lost the plot, hit the wrong button, went off half-cocked earlier. This was supposed to go here but ended up in @Correlli's realm, by mistake. One more crack,

Denuded of all the greenery, otherwise a very nice highlight,
I’ve always got a Broughton HPF patched into the effects loop. Picked up that tip off an SWR forum right about the time I was ready to toss the head. Made all the difference.

I’ve got everything below about 60 Hz dialed out now. And it’s a whole new beast with one of those.

Adding a HPF is the fix. With a HPF the amp runs much cooler and the sound gets pristine. Bye-bye fried cabs too.

The turning point in my journey was getting a Tech 21 Q/Strip as my DI, which has HPF/LPF settings. HPF/LPF has been a bit of a revelation for me.
Perhaps there's a filter out there for taking care of all this variegation too ;)
 
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30 Hz ! ? .... yes please...

Be very careful what you wish for.

Trading off extension for power handling and loudness, do you know what that means?

Also, the fundamental of those low notes plays hell indoors.

Low frequencies are very hard to hear, even harder with other loud sounds going on.

The popularity of the HPF is due to these factors. Lots of guys with 60hz capable cabs high passing even higher for better overall sound.

You can get a hell of a lot louder by making 60hz rather than 30hz, without breaking your woofer.

By all means, build the giant box though! I love Frankenrigs as much as anyone. Indeed a 215 would be a much more sensible thing.
 
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Be very careful what you wish for.

Trading off extension for power handling and loudness, do you know what that means?

Also, the fundamental of those low notes plays hell indoors.

Low frequencies are very hard to hear, even harder with other loud sounds going on.

The popularity of the HPF is due to these factors. Lots of guys with 60hz capable cabs high passing even higher for better overall sound.

You can get a hell of a lot louder by making 60hz rather than 30hz, without breaking your woofer.

By all means, build the giant box though! I love Frankenrigs as much as anyone. Indeed a 215 would be a much more sensible thing.


I've been HPF'ing at 35hz (24db per octave)for something like 6 years...lots of guys think that having sub 30hz is going to be awesome but I've learned:

  • The stuff down in the sub-40hz range makes huge messes in the room. Once you get rid of it, sound engineers will like you way better even at loud volume.
  • Clearing up the room in that range helps your band not suck in FOH. You'll be classified as 'easy to mix' in the 'industry'
  • You're doing what most soundmen are doing anyway...HPFing the bass somewhere between 30-40hz. Your rig is way closer to FOH sound.
  • Players.Won't. Notice. I share my fF rig regularly with openers. Not.a.single.time has a player ever thought it didn't go low enough. I've never had ANYONE volunteer they thought there was a HPF running.
  • What many players and civilians take to be 'deep lows' aren't. They're boosted lows in the range above your HPF. Really. Boosting something like 60-80 or so is the big fat low that people think is at 30 or whatever.