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

[Bassdoggydogg]

I don't know for sure, but it sounds to me like going around the block just to get next door. Why not just turn the presence knob down? Also, what might be really distracting when you're practicing alone might not be noticeable at all in a live mix.

Turning the nob down would decrease the overall grit and totally prevent me from reaching the overdriven sound I need. The shrill clank may or may not appear in the mix, but If I do a bass intro or outro then it would probably stick right out at that point.

I guess I'm just wondering if these filters really cut out the certain frequencies completely or if they just dampen them?

 

[LightForce104]

Turning the nob down would decrease the overall grit and totally prevent me from reaching the overdriven sound I need. The shrill clank may or may not appear in the mix, but If I do a bass intro or outro then it would probably stick right out at that point.

I guess I'm just wondering if these filters really cut out the certain frequencies completely or if they just dampen them?

It’s a slope, so the farther past the shoulder frequency you go, the more attenuation you get.

 

[Bassdoggydogg]

It’s a slope, so the farther past the shoulder frequency you go, the more attenuation you get.

Ok now I get what 12 db per octave means on the Broughton website description. At least I think I do. I feel like this is the answer for keeping tone but not having excess clack? Unless I'm somehow making some wild assumption?

 

[scottfeldstein]

Maybe it's a different thing, but when I slap I just bring down the high mids to get rid of string noise while still maintaining the spicy zing of the top end.

 

[Count Bassie]

Sorry everybody I need to bump-a-ruski this thread for some clarification... I need help dialing out shrill fret noise/clacking that I get from the presence nob on my Sansamp BDDI v2. Will a LPF fully remove the frequencies that make this thing clack too much? Or will it just soften it and still produce some clack?

If you are getting something you like from Presence, the lpf will more likely soften that undesired hi freq. There will still be smacky transients, in part because it's not all hi freqs that the Presence knob is bringing forward.
But, I'd guess that that extra hi freq smack is likely to get partially absorbed by accompanying freqs in your band mix anyway. Try it at your band practice before you get too wrapped up with it, it may be less of an issue than you're thinking.

 

[ecmjazz]

Hello!
What are the options for buying an HPF in Europe? I am wondering about Radial Engineering SB-4, but it uses 48 V phantom power, and that's not very practical for live usage. I am planning to buy Joyo R-12 Band Controller EQ to chase a certain type of sound, and am wondering whether that one could replace the HPF, as the R-12 has 31 Hz and 62 Hz attenuators? I guess that somewhere below 32 Hz still some of the lowest frequencies will still pass, as this is not a true HPF, but each attenuator is rather a notch/bandpass filter?

 

[jb90]

Why you guys need hpf for bass guitar rig? Most of those small cabs are 45-55 or even higher (+/-3db) so why HPF necessary? I'm just curious cause my cab is ported 50-16k cab and I have plenty of bass and I can cranck my amp all the way up and cabinet still hold it without farts or blowing out speakers.

 

[Passinwind]

Why you guys need hpf for bass guitar rig? Most of those small cabs are 45-55 or even higher (+/-3db) so why HPF necessary?

For starters, because anything you throw at the cab below the port tuning frequency makes the cab sound bad above the port tuning as well. The speaker can't reproduce that junk and in many cases it will fail eventually if abused in that way. We're not just making this up, look at some of the Eminence suggested cab configurations and how many are explicitly specified for use with an HPF. It's possible and maybe even likely that in your case your amp already has a built in HPF, as many do.

As far as why I use one in the amps I build, it's mostly for the greater flexibility in tuning the location and shape of the bass control peaking frequency.

 

[Sascha Erni]

Hello!
What are the options for buying an HPF in Europe?

I ordered mine from Josh Broughton, he ships to Europe (and Switzerland). Shipping and dues might look to be out of proportion, but if you bundle your order to include additional pedals, it's not too bad. Also, you might get lucky and find a used / replaced pedal in the forums or on Facebook marketplace.

There's also the Vong kit that's more easily shipped inside Europe. But as said, it's a kit, i.e. you'll need to assemble (or get it assembled) yourself. VONG-Filterung – Schalltechnik_04

Many more or less popular preamp pedals and pretty much all modern amps come with a set-frequency HPF equipped. Some are more tweakable; e.g. the Stanley Clarke signature edition of the EBS Microbass comes with both HPF and LPF and is readily available. (And also, a great preamp.)

 

[jb90]

For starters, because anything you throw at the cab below the port tuning frequency makes the cab sound bad above the port tuning as well. The speaker can't reproduce that junk and in many cases it will fail eventually if abused in that way. We're not just making this up, look at some of the Eminence suggested cab configurations and how many are explicitly specified for use with an HPF. It's possible and maybe even likely that in your case your amp already has a built in HPF, as many do. Look at the pic. It's a freq response chart which have HPF set at 50hz and LSF boosted 16db of 100hz to get 20hz flat. If you need boost your bass (in this example at 100hz) 16db you just don't know what eq works.

As far as why I use one in the amps I build, it's mostly for the greater flexibility in tuning the location and shape of the bass control peaking frequency.

Of course not! You must cranck up bass a lot to make distortion from bass cab. You probably have bad build cab. As I said most cabs have HPF from 45 up to even 70hz so you must put at least 3-6-9db of bass those low end to make it flat. Not mention boost! You just tune cab not amp. If amp have build HPF it's not a real amp. My is flat (+/-1db) on 20-20k. No HPF. HPF is in the cab which is tuned to some freq. Most 45 and up. You don't tune cab with HPF pedal but with building and tuning (ported cabs have 18-24db/oct and sealed 12db/oct).

 

[SoulReflection]

Why you guys need hpf for bass guitar rig? Most of those small cabs are 45-55 or even higher (+/-3db) so why HPF necessary? I'm just curious cause my cab is ported 50-16k cab and I have plenty of bass and I can cranck my amp all the way up and cabinet still hold it without farts or blowing out speakers.

If you think they are pointless, that is your opinion and you are entitled to it.

Those who have read through this thread (as I have) and a few amp manufacturers who have incorporated HPFs, have found instances (proof) and reasons for why they can be helpful.

I, for one, am not going to debate the subject with you. All the best in your bass journey.

 

[jthisdell]

Why you guys need hpf for bass guitar rig? ...

As passinwind said, a high pass filter filters out the lowest frequencies that your cab cannot reproduce, and you cannot hear but do suck up amplifier power and do cause your cab to work too hard trying to reproduce and do result in muddy sound. It is very counter intuitive but you can achieve excellent results by cutting the very lows and also boosting bass frequencies. Good live sound and studio engineers understand this. Almost any halfway decent live sound board will have some sort of hpf, preferably selectable by channel.

 

[SoulReflection]

For starters, because anything you throw at the cab below the port tuning frequency makes the cab sound bad above the port tuning as well. The speaker can't reproduce that junk and in many cases it will fail eventually if abused in that way. We're not just making this up, look at some of the Eminence suggested cab configurations and how many are explicitly specified for use with an HPF. It's possible and maybe even likely that in your case your amp already has a built in HPF, as many do.

As far as why I use one in the amps I build, it's mostly for the greater flexibility in tuning the location and shape of the bass control peaking frequency.

Congrats on your level of patience !

 

[jthisdell]

Those who have read through this thread (as I have) and a few amp manufacturers who have incorporated HPFs, have found instances (proof) and reasons for why they can be helpful...

I think a lot of smaller combos have a built in hpf to minimize damage to their speakers and reduce warranty claims

 

[jb90]

But cabs are not flat from 1hz to 20kHz. Cabs have natural HPF because are tuned. Freq response is (often) +/-3db so below that is a slope which is 12db/oct for sealed and 18-24db/oct slope in ported cabs. So if cab have 50-15k that means 50hz is (+/-3db) and 25hz is -12db to -18/-24db depends on cab build. If you don't boost your bass knob all the way up and don't have cab which is tuned lower than 45-50 you have nothing to do with HPF. It all depends how cab is build and what you do with your eq. It's very hard to blow up cabs these days. You must boost bass A LOT and turn up the volume "at 11" to do that. And still with good cab it's hard to completely damage it. And don't forget that bass have the highest amplitude on 2nd harmonic which still is about 60hz for low B string. Any big distortions are in 20-50hz area so as you can see low B is still above that. Look at that pic below. It;s HPF at 50hz and 100hz 12db/oct shelf boosted 16 DB!!! If you need boost your 100hz bass knob that far you definitely don't know what you do with eq.

 

[SoulReflection]

I think a lot of smaller combos have a built in hpf to minimize damage to their speakers and reduce warranty claims

One normally doesn't add an HPF unless it is needed. Smaller cabs usually display the signs of distress before damage is done. A low powered amp is unlikely to need one if running through a high powered cab, IMHO.

 

[bassically_eli]

Of course not! You must cranck up bass a lot to make distortion from bass cab. You probably have bad build cab. As I said most cabs have HPF from 45 up to even 70hz so you must put at least 3-6-9db of bass those low end to make it flat. Not mention boost! You just tune cab not amp. If amp have build HPF it's not a real amp. My is flat (+/-1db) on 20-20k. No HPF. HPF is in the cab which is tuned to some freq. Most 45 and up. You don't tune cab with HPF pedal but with building and tuning (ported cabs have 18-24db/oct and sealed 12db/oct).

But cabs are not flat from 1hz to 20kHz. Cabs have natural HPF. Freq response is (often) +/-3db so below that is a slope which is 12db/oct for sealed and 18-24db/oct slope in ported cabs. So if cab have 50-15k that means 50hz is (+/-3db) and 25 is 12 too 18-24 depends on cab build.

No offense, but you know just enough to be dangerous. The natural bass roll-off of a cab is not the same as an HPF. If you will damage a speaker by sending it too strong a signal with too much low frequency content. An electronic HPF can reduce the amount of low frequency content in that signal; the cab tuning cannot. So that's benefit #1. Benefit #2 is that your amplifier does not waste its power reproducing undesirable, power-hungry ultra low-frequencies, and benefit #3 is having a tool that can help you tune the low-end the whatever room/space you are playing in.

I see you are in Poland. I apologize if there is a language barrier regarding the term "high pass filter."

 

[bassically_eli]

Another benefit (#4) is that they can be handy in tuning certain pedals, preamps, and FX units. For example, placing an HPF before a compressor or overdrive pedal will change the way it responds.

I mostly play upright bass, and my upright pickup puts out so much low-end content that it is prone to driving many devices into nasty sounding hard clipping. Having an HPF early in my signal chain helps drastically with this.

 

[jthisdell]

I mostly play upright bass, and my upright pickup puts out so much low-end content that it is prone to driving many devices into nasty sounding hard clipping. Having an HPF early in my signal chain helps drastically with this.

Uprights tend to produce a lot of very low rumble noise.

 

[jb90]

No offense, but you know just enough to be dangerous. The natural bass roll-off of a cab is not the same as an HPF. If you will damage a speaker by sending it too strong a signal with too much low frequency content. An electronic HPF can reduce the amount of low frequency content in that signal; the cab tuning cannot. So that's benefit #1. Benefit #2 is that your amplifier does not waste its power reproducing undesirable, power-hungry ultra low-frequencies, and benefit #3 is having a tool that can help you tune the low-end the whatever room/space you are playing in.

I see you are in Poland. I apologize if there is a language barrier regarding the term "high pass filter."

1. Too strong signal? How you can do that from bass guitar? And especially passive one? 2nd harmonic is where amplitude of the note is the highest. Way above subs (even for 5 string bass). It's almost impossible to do that Do you think that bass cab manufacturers don't know that?
2. Amp won't waste power for useless frequencies if you don't crank them up. Simple as that
3. Shroeder freq. Is way above subbass. Mainly 100-300hz so you don't use HPF that high anyway.
Sorry but to blow away your cab you have try realy hard to make it come true. Same with reduce unwanted freq which bass not produce. Not mention amp. If you don't boost you won't add gain to that frequencies. And bass lives in mids + what I write above. Of course you can use HPF - it's up to you and I'm the last person who will forbid anyone to use it, but as I said above, it's 9/10 useless anyway.