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.

[Obrienp]

Having tried to wade through most of this thread, I have convinced myself that it is worth ordering a HPF/LPF pedal. I’ve gone for a Sine Effect C24 (https://sineeffect.com/C24-High-Low-Pass-filter-pedal-p595346070), which seems reasonable at around £137 with postage and was available immediately. TBH, more than I have paid for a pedal in a long time but none of the usual online sources seem to carry these kinds of pedals and this is UK made. Anybody got any experience of them?

 

I am hoping it will come with some instructions/recommendations for placement in the signal chain, as views are very mixed on this thread. My current thoughts, for what they are worth, are that it depends on what I am using.  I’m thinking that when I use the my Flyrig V 2 into a power amp/desk the C24 should be after the Flyrig. Using the Mark Bass LM111 into either a LFSys Monza, or BF Two10 S: after the tuner pedal but before any other effects pedals I might use (chorus, overdrive, compressor, envelope filter). The quandary comes when considering my Blackstar U700 with the aforementioned cabs. The U700 has a bunch of built in affects, plus preamp and power amp voices. I am thinking the C24 probably needs to go into the effects loop so it is after all the above because they might be adding a whole load of unnecessary frequencies into the signal.

 

Its probably quite clear from the above that I haven’t really got my head round this, so any advice or views would be welcome.

 

Final noob question: will the low pass filter act like an attenuator on the LFSys Monza’s compression driver? It’s great having FRFR but sometimes I also want to dial in a bit more of a vintage feel. Both the U700 and the LM 111 are quite good at providing that old school tone when you want it but I sometimes get some additional harsh/brittle artefacts that  come through the compression driver. It would be nice to be able to prevent that getting through.

[paul_5]

First of all Obrienp- do it. Mine has been an absolute game changer. I was thinking about getting a louder amp before using a HPF, as it was running at full tilt all gig, every gig, now I’ve actually got some headroom to spare.

 

secondly, I’ve placed mine as the last thing in the chain, just before the amp. I tried it at the start, but my envelope filter didn’t quite react the same so I moved it. Try it in different positions and see what works best for your setup.

[Obrienp]

1 hour ago, paul_5 said:

First of all Obrienp- do it. Mine has been an absolute game changer. I was thinking about getting a louder amp before using a HPF, as it was running at full tilt all gig, every gig, now I’ve actually got some headroom to spare.

 

secondly, I’ve placed mine as the last thing in the chain, just before the amp. I tried it at the start, but my envelope filter didn’t quite react the same so I moved it. Try it in different positions and see what works best for your setup.

Actually your first point was very much on my mind. Both my main gigging amps are not really driving my LFSys Monza anywhere near its max of 600 watts into 8 ohms. Now as it happens 300 watts is probably more than enough for any of my gigs but I don’t really like the idea (or the sound) of these amps flat out. I could do with more clean headroom from the amps (no problem with the cab). If the HPF avoids me having to shell out on an amp that can get closer to 600 watts @ 8 ohms, all the better.

 

Its sounds like some experimentation, on placement in the signal chain, is going to have to take place.

[Stub Mandrel]

2 hours ago, Obrienp said:

Final noob question: will the low pass filter act like an attenuator on the LFSys Monza’s compression driver? It’s great having FRFR but sometimes I also want to dial in a bit more of a vintage feel. Both the U700 and the LM 111 are quite good at providing that old school tone when you want it but I sometimes get some additional harsh/brittle artefacts that  come through the compression driver. It would be nice to be able to prevent that getting through.

 

Unlikely, a good HPF won't affect those upper frequencies at all.

[Obrienp]

1 hour ago, Stub Mandrel said:

 

Unlikely, a good HPF won't affect those upper frequencies at all.

I was thinking of the LPF in the C24.

[Obrienp]

I think I may have my answer to my noob question, as the C24 has already arrived, which is amazing: less than 24 hours from placing my order. A nice little unit. Very nicely made. You wouldn’t know these are a small production item. 
 

I have had a brief play with the unit, putting it after a Battalion preamp, before my power amp and then into the LFSys Monza. I tried a P Bass (32” scale) with Tone Rider pickup and then a Guild Starfire 1 (the p pickup one) tuned down a semitone. Setting the HPF just under 40 Hz and the LPF a bit over 1KHz is interesting. It has an apparent reduction in volume, which is cured by the boost control. I’m still not sure whether I like the HPF effect but it does seem to make cabinet response clearer. The LPF is certainly doing something to get rid of the brittle overtones, at the risk of making it all sound a bit muffled. It does get rid of the huge transition I was experiencing on the Guild between the A and D strings. With the LPF engaged, I don’t feel that the top two strings are competing as much with the guitars. How that will affect the bass in the mix I’m not sure.
 

Obviously more experimentation is needed. Also the Monza is known for having a very tight bass response already, so perhaps the HPF is having less effect at the lower end. I am guessing the HPF/LPF combination may do more for the BF Two10 that can sound pretty muddy on occasions. Also I haven’t tried my amps yet, or any effects beyond compression and drive (from the Battalion).

[Downunderwonder]

6 hours ago, Obrienp said:

I think I may have my answer to my noob question, as the C24 has already arrived, which is amazing: less than 24 hours from placing my order. A nice little unit. Very nicely made. You wouldn’t know these are a small production item. 
 

I have had a brief play with the unit, putting it after a Battalion preamp, before my power amp and then into the LFSys Monza. I tried a P Bass (32” scale) with Tone Rider pickup and then a Guild Starfire 1 (the p pickup one) tuned down a semitone. Setting the HPF just under 40 Hz and the LPF a bit over 1KHz is interesting. It has an apparent reduction in volume, which is cured by the boost control. I’m still not sure whether I like the HPF effect but it does seem to make cabinet response clearer. The LPF is certainly doing something to get rid of the brittle overtones, at the risk of making it all sound a bit muffled. It does get rid of the huge transition I was experiencing on the Guild between the A and D strings. With the LPF engaged, I don’t feel that the top two strings are competing as much with the guitars. How that will affect the bass in the mix I’m not sure.
 

Obviously more experimentation is needed. Also the Monza is known for having a very tight bass response already, so perhaps the HPF is having less effect at the lower end. I am guessing the HPF/LPF combination may do more for the BF Two10 that can sound pretty muddy on occasions. Also I haven’t tried my amps yet, or any effects beyond compression and drive (from the Battalion).

Generally you won't hear HPF in action until things get well loud or you overdo the frequency selection.

 

For whatever volume you are playing at you can raise the HPF until it sounds thin and then back it off.

 

Some rooms are overly lush down in the low end. I can wind up at 80hz with a bass cut.

[ossyrocks]

I've just ordered my first HPF.

 

I am very happy with my current setup, an old GK RB series head into a BF 3x10. But I've had a vintage Fender Bassman 50 entirely rebuilt and modified and I want to try it at small gigs.

The issue I have with the Bassman is that with my P bass with flats and the BF cab there's so much low end that I just can't get the amp up to where it needs to be. I can feel and hear the amp wasting its time trying to amplify all the lower frequencies and I think it's using up a great deal of its power doing that. 

It will be an interesting experiment anyway. If I end up with a giggable 50w valve head, that will be nice.

I've gone for the Rafferty clone of the Fdeck HPF. There's a few weeks to wait whilst he builds it though. I'll report back when I have tried it out.

Rob

[Obrienp]

I used my C24 HPF/LPF at a NYE gig. I was using a Barefaced Two10 with an LFSys Monza on top (making 3 x 10) driven by a Blackface U700, which can handle the 2.7 ohm load. HPF set at the lowest frequency of 30 Hz and LPF at around 4K. I had the gain control set to give a slight boost over the dry signal. This combination was definitely thickening up the tone (which seems counterintuitive) and removing any brittle high end. I wasn’t running the amp anywhere near max volume, as I was DI’d into the PA, so I can’t tell how much extra clean headroom the filter will give me. The effect seemed to be a bit like a compressor but I guess it wasn’t smoothing out the dynamics. I definitely liked the effect and kept the unit on through most of the gig. I only switched it off when I really wanted the top end to pop.

 

The bass was a Maruszczyk Elwood (Jazz copy) 4a 32”, which I use almost exclusively in passive mode.

[Rodders]

I set the HPF (labeled Low Cut) on my Fishman Preamp to between 60-80Hz, 1st harmonic frequency of a Low D or E, I tried setting it lower around 30-40 but still found it a bit muddy. I boost the bass knob on the EQ if the Sound Engineer reckons it needs it. 

I use my Dingwall ABZ 4 through a Warwick Gnome & Schroder 12PL majority of the time, picked up a  Sine Effect C24 secondhand but I've yet to experiment with it much, I use it on a smaller setup that lives at a rehearsal room.