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

Our designer picked 3 kHz because that is kind of a midpoint "sweet spot" for that function. The roll off starts at that point and attenuates a 12dB per octave. You can easily raise that point to 6 kHz by using the 18dB mid shift as well as lower the LPF. Don't get hung up on the numbers, just use your ears. Even with a typical guitar speaker, the high's will start to roll of around 5 kHz (like the 810e you referenced) but much higher frequencies are still present but are attenuated.
I think that's a fair reply, Chris. Thx for the info!
 
I got my Broughton always-on HPF and I'm ready to give it a whirl later tonight. The specs on it are that the knob goes from 25 Hz to 190 Hz. My GK Neo cabs are rated to go as low as 45. I think I'll try tuning the filter to about 50 and see what that sounds like. I'm leaning towards putting it the beginning of my pedal chain, just counting on my ears to keep subsequent effects under control. We'll see.
 
I got my Broughton always-on HPF and I'm ready to give it a whirl later tonight. The specs on it are that the knob goes from 25 Hz to 190 Hz. My GK Neo cabs are rated to go as low as 45. I think I'll try tuning the filter to about 50 and see what that sounds like. I'm leaning towards putting it the beginning of my pedal chain, just counting on my ears to keep subsequent effects under control. We'll see.
You may find that the 50-60Hz range for the HPF works very well and actually gives you a clearer, more solid bass tone for reasons not directly related to that cab spec. However, I will admit that keeping a cab in its comfort zone from a design envelope perspective has merits in the areas of tone and longevity.
 
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Just came home for lunch and my broughton l+hpf was on my door step, two days early i might add. Only could give it a try for about 5 mins but it seems like just what i needed. I had it set at 40hz and 1.6k and liked that alot. Will have to do further testing and knob twiddling on both it and my amp to see what i can get out of it. I really like the very clean gain knob, thumbs up
 
I got my Broughton always-on HPF and I'm ready to give it a whirl later tonight. The specs on it are that the knob goes from 25 Hz to 190 Hz. My GK Neo cabs are rated to go as low as 45. I think I'll try tuning the filter to about 50 and see what that sounds like. I'm leaning towards putting it the beginning of my pedal chain, just counting on my ears to keep subsequent effects under control. We'll see.

Just came home for lunch and my broughton l+hpf was on my door step, two days early i might add. Only could give it a try for about 5 mins but it seems like just what i needed. I had it set at 40hz and 1.6k and liked that alot. Will have to do further testing and knob twiddling on both it and my amp to see what i can get out of it. I really like the very clean gain knob, thumbs up

Also try turning the Bro HPF about 10hz higher and tweaking with your amp's bass tone knob. You'll be able to hear some changes, hopefully for the better.
 
Also try turning the Bro HPF about 10hz higher and tweaking with your amp's bass tone knob. You'll be able to hear some changes, hopefully for the better.

I haven't tried a thing yet, but it's already occurred to me that setting the HPF relatively high and then turning up the bass frequencies a bit on the amp might be a nice combo to try.
 
I live in a small apartment, so I don't usually get an opportunity to assemble the big rig outside of a large outdoor stage. Today I did so in the living room of a big house that I'm minding while a friend is away. I set up the HPF, Turned it all the way down (25 Hz) and then brought it up to about a quarter turn, figuring that was about 50 or thereabouts, and let my looper loose. Immediately there was a problem.

Last week I had replaced a blown speaker and had EQd my amp and Warwick bass to sound pretty reasonable. Pretty flat, just a slight cut around 500 Hz. But today it didn't sound right. You'll all probably recognize right away that I'm an idiot, but it took me a good 15 minutes to realize that I had the knob on the HPF wrong. I was cutting the signal at around 120 Hz, not 50. I put one hand on my master volume and the other on the HPF frequency knob...and observed the magic.

Once I had that 1/4 turn dialed in I could hear it. I had a full, deep tone. If I turned it down all the way, however, I had additional mud. Turn it back up to that 1/4, around 50 Hz or so, and no more mud.

This is going to be great. I'll spend the next week or two dialing in this gem and organizing the rest of my board–all with the big rig blasting. I'm going to need more patch cables and velcro before I'm done. More soon.
 
I live in a small apartment, so I don't usually get an opportunity to assemble the big rig outside of a large outdoor stage. Today I did so in the living room of a big house that I'm minding while a friend is away. I set up the HPF, Turned it all the way down (25 Hz) and then brought it up to about a quarter turn, figuring that was about 50 or thereabouts, and let my looper loose. Immediately there was a problem.

Last week I had replaced a blown speaker and had EQd my amp and Warwick bass to sound pretty reasonable. Pretty flat, just a slight cut around 500 Hz. But today it didn't sound right. You'll all probably recognize right away that I'm an idiot, but it took me a good 15 minutes to realize that I had the knob on the HPF wrong. I was cutting the signal at around 120 Hz, not 50. I put one hand on my master volume and the other on the HPF frequency knob...and observed the magic.

Once I had that 1/4 turn dialed in I could hear it. I had a full, deep tone. If I turned it down all the way, however, I had additional mud. Turn it back up to that 1/4, around 50 Hz or so, and no more mud.

This is going to be great. I'll spend the next week or two dialing in this gem and organizing the rest of my board–all with the big rig blasting. I'm going to need more patch cables and velcro before I'm done. More soon.
You are a brave man doing that on a house sit.
 
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Pretty much every amp I have designed over the last 20 years includes at least a fixed HPF.

Depending on the intended application of the amp, it's typically somewhere in the high 20's Hz to low 30's Hz.


Sir, could you please kindly clarify where in an amp is the built-in HPF usually placed? Is it the preamp section or the power section? In other words: does the built-in HPF influence DI? Thank you.
 
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Sir, could you please kindly clarify where in an amp is the built-in HPF usually placed? Is it the preamp section or the power section? In other words: does the built-in HPF influence DI? Thank you.
I can’t speak for all amp designs, but I will use the D-800+ as an example. The block diagram in the manual puts the HPF at the beginning of the EQ section, before the voicing control. With this amp, the DI pre/post selection switch will dictate whether or not the HPF is part of the DI signal.
 
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I can’t speak for all amp designs, but I will use the D-800+ as an example. The block diagram in the manual puts the HPF at the beginning of the EQ section, before the voicing control. With this amp, the DI pre/post selection switch will dictate whether or not the HPF is part of the DI signal.

Thank you. That makes sense...and it is the most flexible solution, IMHO. I wonder whether other manufacturers approach the issues in the same manner.
 
Sir, could you please kindly clarify where in an amp is the HPF usually placed? Is it the preamp section or the power section? In other words: does the built-in HPF influence DI? Thank you.
Plugging your bass directly into an HPF pedal first then the amp (or other effects), as has been stated many times by @agedhorse, to get rid of amplified artifacts (sub-sonic mud) as soon as possible in the signal chain, is its most appropriate use.

It does effect the DI, IMO, in a good way.
 
My personal assumption is that most would have it at the beginning of the eq stage. Still dependant on the pre/post switch.

I checked the Block Circuit Diagram of Genz Benz Shuttle 3.0 (one of my amps) and (without any technical education) it seems to me that the solution is the same as with D-800+ (the HPF is the first step of the preamp allowing it to be by-passed by the "pre" button). If it is the case, I am glad that I have the option of sending the FOH a signal unaffected by the built-in HPF...

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