High Pass Filters

[Chienmortbb]

59 minutes ago, Stub Mandrel said:

My view (which may be a minority one) is that the troublesome frequencies from handling noise putting your palm on the strings etc. are effectively sub-audible, that is below 20 Hz where we hear them as a 'purr' or thump rather than a musical tone.

 

This is full octave below our E string and well below even a low B at 32 Hz, so a 12 or 18dB/octave filter at 30Hz will stop all the non-musical sounds like a wall with minimal effect on the fundamentals if our equipment is able to reproduce them.

 

Personally, I would only look at a higher frequency (say 50Hz) if I was using a speaker with limited high-end response or a lower power amplifier and I wanted the extra headroom.

Theoretically  yes  but in fact the Low B is not necessary or at least it's fundamental is not. When I did play 5 string I never needed a low B and in fact it usually sounds bad. Duke Le Jeune of AudioKinesis tunes his Thundrchild cabs to -3dB at the second fundamental, usually 62Hz  for the 15" and 82Hz for the 12s. While that may be a bit extreme, @Passinwind of the parish over the pond loves his AK cabinet.

 

Very few current or classic  cabs can reproduce the fundamentals of 4 of 5 strings so it is sensible to HPF at any frequency the cab cannot really reproduce. My minimum would be 35Hz at 12dB/Oct but anything up to 50 makes little difference to the sound.

[itu]

In practise all frequecies between DC and 30 Hz are just power eaters. Considering that most of the cabinets start producing something feasible from 60 - 80 Hz area, means that up to DC - 80 Hz could be cut away. @Downunderwonder 's method of setting the f is simply brilliant: use your ears.

 

I expand his idea to other spaces, too. When you go to a new place, the space (room, pub, venue...) is also a new resonator. If it is different in any dimension than the previous one, it has different standing waves. I have a faint vision that the 100 Hz that was mentioned earlier may have had something to do with the room and its dimensions or construction.

 

I love multi band parametric eqs just because any boomy noise can be tamed with one. I am pretty amazed that their use is so limited. It's a HPF + eq in one single package.

[Downunderwonder]

10 minutes ago, itu said:

When you go to a new place,

I think I probably posted about that earlier in this thread.

 

One room blooms luscious bass so well the HPF has to go right up. Pack down and go to another room and it's insipid until HPF put back.

[Stub Mandrel]

23 minutes ago, Chienmortbb said:

Theoretically  yes  but in fact the Low B is not necessary or at least it's fundamental is not. When I did play 5 string I never needed a low B and in fact it usually sounds bad. Duke Le Jeune of AudioKinesis tunes his Thundrchild cabs to -3dB at the second fundamental, usually 62Hz  for the 15" and 82Hz for the 12s. While that may be a bit extreme, @Passinwind of the parish over the pond loves his AK cabinet.

 

Very few current or classic  cabs can reproduce the fundamentals of 4 of 5 strings so it is sensible to HPF at any frequency the cab cannot really reproduce. My minimum would be 35Hz at 12dB/Oct but anything up to 50 makes little difference to the sound.

 

My cab has a -3dB point at 35Hz. An (utterly different) Ampeg 8x10 SVT is 40Hz or 50Hz for the high power version, so plenty of cab styles do go low(er).

I'm happy with 30Hz, not because it needs to be that low, but because it doesn't need to be any higher, at least with my kit (which has plenty of headroom).

 

11 minutes ago, Downunderwonder said:

One room blooms luscious bass so well the HPF has to go right up. Pack down and go to another room and it's insipid until HPF put back.

 

I find my amps bass control is enough to tame boomy rooms.

[Beer of the Bass]

I encountered my first instance of a boomy room/stage where a variable HPF greatly improved things this week. I have a Schalltechnik Vong HPF + LPF on my pedalboard, my main purpose of which is to make my fuzz sound palatable with the LPF when using a DI. But at this gig we were in a village hall, hollow portable stage, vocal PA only and using my Ampeg PF50T with two 1x12" cabs. I was struggling with boomy low notes while we were setting up, and raising the HPF on the pedal cleaned it up with less thinning of the rest of the sound than with the bass control on the amp.

It's literally the first time I've had this issue in several years of using this setup, but I was glad to have the HPF there.

[mouthmw]

Broughton BBA at the start of my chain (to filter out subsonic and ultrasonic frequencies, say around below 20 Hz and above 20 kHz) and Broughton HPF at the end of my chain, which I usually set at 60 Hz.
This gives me a gorgeous tight low end, and my live rig (GK 2001RB and 410 RBH) now sounds like a cleaned up sealed cab + amp. Perfect for vintage style P + flats tones. Great control for boomy rooms too.

[Stub Mandrel]

After reading recent posts, I have shifted my hpf from first to after the compressor and octaver.

 

Much quieter.

 

The compressor exaggerated the noise when not playing, and the octaver seemed to bring some hf noise into the high audio band. Both ok on their own but with compressor and octaver on and after the hpf it was intrusive when not playing.

[Joe_L]

Yes, get one, if you haven't on the 7 years since the original post! Just to save your amp and speaker if nothing else.

[paul_5]

Do it. I built one after using a 300W head that *STILL* wasn't loud enough - heavy hitter on the drums and a brace of guitarists with 100W Marshalls. I tried it as an experiment before shelling out on an even louder head and it saved me a TON of money.

 

FWIW I used John K's layout and had to buy a pair of 2N4416 transistors (£7 each) but it was well worth it.

[Homatron]

This thread inspired me to give an HPF a go too.

 

I went with the Schalltechnik Vong HPF kit and built it in a lunchtime. Only trialled at home so far but I'm pleased with the outcome. I was worried that it would do bad things when using a -1 octave but it may even sound better*!

 

*biased opinion warning.

[Chienmortbb]

1 hour ago, Homatron said:

This thread inspired me to give an HPF a go too.

 

I went with the Schalltechnik Vong HPF kit and built it in a lunchtime. Only trialled at home so far but I'm pleased with the outcome. I was worried that it would do bad things when using a -1 octave but it may even sound better*!

 

*biased opinion warning.

As you may know, there is a speaker design software called WINisd. IT has the option to add filters before the speaker. If you put an HPF in line even putting the-3dB point at 40Hz it makes almost no difference to the speaker response but does make your speaker headroom much great headroom and cleans up your soggy bottom.

[Homatron]

Thanks @Chienmortbb! I had seen the software mentioned on BC but hadn't thought about using it in that way. Sounds like a good place to nerd out! I'll take a look.