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

[mesaplayer83]

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.

Agreed 100% on all of the above - ESPECIALLY the part about soundmen... The first time I played the Turning Stone with my new HPF-3 and showed it to the soundman before soundcheck, he told me he had already been high passing me at around 40 since the first time I played there... After the show, he told me he didn't need to any more, as long as I kept doing what I was doing that night...

 

[Passinwind]

Back on topic, has anyone DIY'd op-amp based active filters for bass? I used to work with very low frequency active filters quite a bit. I think it could be fun.

That's crazy talk Bro.

 

[Craig4003]

Or maybe just don't mess with the text colors in your comments and let the site figure out how to display it well?

 

[NKBassman]

Or maybe just don't mess with the text colors in your comments and let the site figure out how to display it well?

That's no fun.

This will be my last off topic post, I promise.

 

[Passinwind]

That's no fun.

Quoted for posteriority.

For a good time call: NoSquint Plus – Add-ons for Firefox . No need to hang with the limited choices TB offers.

 

[BurningSkies]

Agreed 100% on all of the above - ESPECIALLY the part about soundmen... The first time I played the Turning Stone with my new HPF-3 and showed it to the soundman before soundcheck, he told me he had already been high passing me at around 40 since the first time I played there... After the show, he told me he didn't need to any more, as long as I kept doing what I was doing that night...

See, exactly. Most good soundmen are doing this already. They're not telling you, but it's happening. Part of the problem with loud stage volume isn't volume per-se...it's all that crap deep down that the soundman is trying to get rid of in the bass signal, that most bass rigs are terrible at producing anyway (if you did want to go that low, your cab probably sucks at that deep stuff and it doesn't sound clean, clear or coherent anyway).

I did have one guy in VT who's a bit of a know-it-all tell me that he didn't think my HPF was doing what I said...and I swept up the second filter to show him it was indeed doing what I said.

I certainly don't mind redundant HPFs running in that range either. I used my HPF3 along with the DSP HPF on my Peavey power amp for a long time.

That's crazy talk Bro. View attachment 2972687

Of course it is. Which goes without saying why you've done it and re-done it half a dozen times.

 

[BadExample]

Of course it is. Which goes without saying why you've done it and re-done it half a dozen times.

But purple scares me

 

[superheavyfunk]

But purple scares me

Not me! I want one. drool

 

[BadExample]

Not me! I want one. drool

I think it's a one off, and it's very cool... sounds great!

 

[Passinwind]

I think it's a one off, and it's very cool... sounds great!

Yep, that was a demo unit that I had at NAMM 2017 and last Year's Seattle BassCon, used to gather user feedback to help improve the TB open source preamp project. So anyone is welcome to roll their own as they see fit, and eventually even the enclosure graphics will be true open source as well. You happened to be in the right place at the right time for an at-cost sale, which is actually a very rare scenario since I usually tend to recycle older test builds.

Still hoping that someone else will step up in a similar fashion with a DIY variable HPF stomp box.

 

[RoadRanger]

Still hoping that someone else will step up in a similar fashion with a DIY variable HPF stomp box.

Fdeck publishes his schematics and they are pretty easy to build:
Invalid Link Removed
hpftechllc

 

[Passinwind]

Fdeck publishes his schematics and they are pretty easy to build:
Invalid Link Removed

Yep, but that's his older 2nd order (12dB/oct) version, and is maybe optimized more for upright bass than BG, although quite a few BG players have reported good results as well.

 

[RoadRanger]

Yep, but that's his older 2nd order (12dB/oct) version, and is maybe optimized more for upright bass than BG, although quite a few BG players have reported good results as well.

I've used mine with both active and passive EBG no prob - great for getting the most out of smaller tube amps . In that usage I love that I'm not adding any op amps or bipolar transistors to my signal path .

BTW I might still have a fixed frequency 12dB/oct peaking HPF that I built back in the early 80's out in the garage someplace - probably using a quad op amp (LM324?).

 

[Passinwind]

I've used mine with both active and passive EBG no prob - great for getting the most out of smaller tube amps . In that usage I love that I'm not adding any op amps or bipolar transistors to my signal path .

I based my speculation about the older fdeck versions being better for AUB mostly on my experience with the 12 dB/oct HPF in my old Acoustic Image Focus amp, but of course all of this stuff is as subjective as it gets.
If you like FETs, @fdeck is your man, for sure. It's pretty much all sand to me regardless of device type, but I tend to like most of it more often than not for what I do on bass these days.

...............................................

 

[SoulReflection]

I find this HPF topic very interesting. Does anyone know when it was determined to be necessary and how it evolved?

 

[BadExample]

I've used mine with both active and passive EBG no prob - great for getting the most out of smaller tube amps . In that usage I love that I'm not adding any op amps or bipolar transistors to my signal path .

BTW I might still have a fixed frequency 12dB/oct peaking HPF that I built back in the early 80's out in the garage someplace - probably using a quad op amp (LM324?).

What's wrong with op amps?

 

[mesaplayer83]

I find this HPF topic very interesting. Does anyone know when it was determined to be necessary and how it evolved?

Soundmen have been High Passing signals for a very long time - it just took a while for bass players in the know to catch on to the benefits of it...

 

[xk49w]

I find this HPF topic very interesting. Does anyone know when it was determined to be necessary and how it evolved?

All bass amplifiers have HPFs. Some are better than others. Some people tried external HPFs and liked them. That's pretty much it IMO.

 

[GrapeBass]

The benefit of having a specific pedal born HP/LP Filter is that you have the option of using it 'always on' OR as a specific 'effect' for narrowing your tonal bandwidth. It's also nice to have if you're going direct into a board fro recording. Broughton also added the gain essentially enabling you to punch through when needed. Since it's not a filter that will color your tone, it fits in pretty seamlessly if you don't over do it.

 

[SoulReflection]

All bass amplifiers have HPFs. Some are better than others. Some people tried external HPFs and liked them. That's pretty much it IMO.

Interesting. Do the Fender Combo's have HPF's and how are set?