High Pass Filters

[Owen]

22 hours ago, AREA said:

Of Course. I've had the full sized Vong, but only had used the HPF, so the Mini does exactly what i need plus i have won some space on my Board 🙂

I have gone in to get a price on the grown up Vong. I shall report back.

[Passinwind]

On 09/06/2020 at 01:21, Jus Lukin said:

Yeah, filter curves are additive (even when subtracting!😄) so the Vong would be -24db/Oct below 30hz, similar to a Thumpinator, with an additional variable -12db/Oct above that for tuning to a cab or tone shaping.

I've floated the idea of something like this pedal with a couple of custom builders and after much bemusement and explanation came away with some pretty prohibitive prices. In fact the difference seems so much that I'm off to start a thread about getting a couple of these built!

It a really simple build, and fDeck has published the schematic for his v3 now. I could knock off a board layout very quickly, but he's a friend and even though he's said he'd be OK with that I'd rather not. I've done a design during lockdown for a 12dB/oct one with a resonance control that will be open source and intended for DIY builders, just have to build one myself and make sure it performs as expected.

Edited June 10, 2020 by Passinwind

[John Sl]

This thread is so interesting, although some of the technical stuff is beyond me.  Like others I use the AcBsPre in the B3 to cut the very low frequencies, to reduce the load on the speakers.

Typically I use patches AcBsPre/Graphic eq/agamp for cleaner sounds and AcBsPre/Graphic eq/SVT for a bit of distortion.  
I set the low mids on the AcBsPre to 63 or 70 Hz and the amp sim mids to 70 or 80 Hz.

 I set the Depth to 6 or 7 then adjust frequencies as follows to push the curve up and get a steeper slope:

40 Hz    AcBsPre Bass

50         Graphic eq

63         AcBsPre

70         amp sim or AcBsPre

80        amp sim

I check the frequencies on an old version of Audacity.  With a peak of about -15dB, 30 Hz is down at about -45, which is fine for my purposes.

This gives me an articulate bottom end; or am I talking out of my a**e ?!

[Chienmortbb]

26 minutes ago, John Sl said:

This thread is so interesting, although some of the technical stuff is beyond me.  Like others I use the AcBsPre in the B3 to cut the very low frequencies, to reduce the load on the speakers.

Typically I use patches AcBsPre/Graphic eq/agamp for cleaner sounds and AcBsPre/Graphic eq/SVT for a bit of distortion.  
I set the low mids on the AcBsPre to 63 or 70 Hz and the amp sim mids to 70 or 80 Hz.

 I set the Depth to 6 or 7 then adjust frequencies as follows to push the curve up and get a steeper slope:

40 Hz    AcBsPre Bass

50         Graphic eq

63         AcBsPre

70         amp sim or AcBsPre

80        amp sim

I check the frequencies on an old version of Audacity.  With a peak of about -15dB, 30 Hz is down at about -45, which is fine for my purposes.

This gives me an articulate bottom end; or am I talking out of my a**e ?!

I do not know the preamp or model you are using, but there is no good stuff at 30Hz even if you plat 5 string. It will not hurt at all. In that region, all you get is excessive power being used for moving the speaker slowly. You are protecting your speaker and, as you say, tightening your sound.

[fretmeister]

When I get paid again I will be ordering one of these

 

https://sineeffect.company.site/H24-high-pass-filter-24dB-octave-p553986284

 

Just the thing to dial it in for the room. More versatile than the Micro Thumpinator.

[Chienmortbb]

9 hours ago, fretmeister said:

When I get paid again I will be ordering one of these

 

https://sineeffect.company.site/H24-high-pass-filter-24dB-octave-p553986284

 

Just the thing to dial it in for the room. More versatile than the Micro Thumpinator.

That will open your eyes,whe. You take the filter higher and higher and realise how little the real low end really contributes to your sound. We all know what frequencies the E and B strings are but it is really the 2nd harmonics, around 60 and 80Hz that we hear. 
 

[Al Krow]

4 hours ago, Chienmortbb said:

That will open your eyes,whe. You take the filter higher and higher and realise how little the real low end really contributes to your sound. We all know what frequencies the E and B strings are but it is really the 2nd harmonics, around 60 and 80Hz that we hear. 

 

I think more accurate to say 1st harmonics at approx. 60Hz and 80Hz (if fundamental is at 31 Hz and 41Hz)? But take your point.

 

14 hours ago, fretmeister said:

When I get paid again I will be ordering one of these

 

https://sineeffect.company.site/H24-high-pass-filter-24dB-octave-p553986284

 

Just the thing to dial it in for the room. More versatile than the Micro Thumpinator.

 

That did look really good on the separate thread you started on this one. I've consequently sold my trusty Thumpinator I've had on my board for several years! (Just need to check what the HPF capability is on my Boss multifx before getting one of these as a replacement).

[ped]

I wouldn't mind an HPF to go under my desk for my bassboard. Ideally no footswitch, always on type job. Any recommendations?

[scrumpymike]

11 minutes ago, ped said:

I wouldn't mind an HPF to go under my desk for my bassboard. Ideally no footswitch, always on type job. Any recommendations?

 

This was the best I could find but they're charging $40 p&p on top of the $70 cost to ship to the UK! I'm now the proud owner of one recently brought back by friends visiting his son out there 🙂

 

https://www.broughtonaudio.com/product-page/always-on-high-pass-filter

[ped]

38 minutes ago, scrumpymike said:

 

This was the best I could find but they're charging $40 p&p on top of the $70 cost to ship to the UK! I'm now the proud owner of one recently brought back by friends visiting his son out there 🙂

 

https://www.broughtonaudio.com/product-page/always-on-high-pass-filter

 

Cheers yeah one like that would be great.. will keep my peepers open

[MartinB]

There's a build-it-yourself always-on -12dB/oct (equivalent to the Broughton) if you're handy with a soldering iron: https://www.musikding.de/MINI-HP-VONG-filter-kit

[ped]

4 minutes ago, MartinB said:

There's a build-it-yourself always-on -12dB/oct (equivalent to the Broughton) if you're handy with a soldering iron: https://www.musikding.de/MINI-HP-VONG-filter-kit

 

Alas, that I am not

[SuperSeagull]

I have a Rafferty HPF that I bought on here. I have no real understanding of how it works (despite having a son with a PhD in Acoustics who is also an excellent guitarist) but I know it does something subtle but wonderful to my sound. I adjust the freq control to the point that it sounds a bit rubbish then dial it back a bit. Everything seems to tighten up. I now need to see what the phase switch does!

[tauzero]

7 hours ago, Al Krow said:

I think more accurate to say 1st harmonics at approx. 60Hz and 80Hz (if fundamental is at 31 Hz and 41Hz)? But take your point.

 

No, second harmonic is correct. Third harmonic is three times the frequency, fifth harmonic is five times, etc.

[Al Krow]

20 hours ago, tauzero said:

 

No, second harmonic is correct. Third harmonic is three times the frequency, fifth harmonic is five times, etc.

Yes, thanks, you and @Chienmortbb are both correct i.e. fundamental and first harmonic are interchangeable terms so the next one up from the fundamental is the second harmonic not first harmonic.

[Al Krow]

On 18/08/2023 at 09:49, Chienmortbb said:

That will open your eyes... You take the filter higher and higher and realise how little the real low end really contributes to your sound. We all know what frequencies the E and B strings are but it is really the 2nd harmonics, around 60 and 80Hz that we hear. 

 

Not disagreeing that bass can generally be usefully cut with an hpf, there are definitely occasions when you want a powerful low end (as I think we mentioned elsewhere).

 

Two examples might be:

- reggae bass;

- a club dance vibe.

 

In such cases having the right kit to deliver a big low end, without it just being mud, is going to be key and typically is going involve decent sub-woofer(s) added to the tops. Beyond what my lot currently has in terms of kit, but we recently went through a pair of RCF 15" subs plus high quality tops at a function where we were sharing the PA kit of a pro DJ, and it was such a good sound! 

[jrixn1]

21 hours ago, SuperSeagull said:

I adjust the freq control to the point that it sounds a bit rubbish then dial it back a bit.

 

+1.  Many people go by a specific frequency or number on a dial - but yours is the correct way!

 

 

Quote

I now need to see what the phase switch does!

 

Francis Deck (designer of the Rafferty) puts it like this:
"Flip the phase switch. The feedback will get worse, or better. You want it to be better."

🙂

 

 

Edited August 19, 2023 by jrixn1

[Mottlefeeder]

The attached PDF is a 2018 copy of FDeck's 12dB +12dB HPF design notes, and a tested and proven guitar-fx stripboard layout. 

Note, the user opted for a TL074 with a 9v supply, but it is not recommended for use at less than 10v

David

 

 

 

 

 

 

 

downloadfile.PDF

[Stub Mandrel]

My design...

 

 

24dB / octave with the -3dB point at 30Hz.

 

Chosen to barely affect the low B, while almost completely removing subsonic rumbles.

[msb]

On 18/08/2023 at 11:07, scrumpymike said:

 

This was the best I could find but they're charging $40 p&p on top of the $70 cost to ship to the UK! I'm now the proud owner of one recently brought back by friends visiting his son out there 🙂

 

https://www.broughtonaudio.com/product-page/always-on-high-pass-filter

 

I’ve been a fan of Broughton, it’s just a little one man shop in Toronto but he’s managed to generate worldwide acclaim. His stuff is beautifully designed , really well built , and always services a distinct need.

I’ve got the Hi/Low pass filter on the way.

 

[BassAdder60]

I’ve discovered the benefits of HPF and LPF in my new Genzler 4 on the floor pedal ( on the drive part ) 

 

Really makes a difference in a good way 

[Downunderwonder]

13 hours ago, Al Krow said:

 

Not disagreeing that bass can generally be usefully cut with an hpf, there are definitely occasions when you want a powerful low end (as I think we mentioned elsewhere).

 

Two examples might be:

- reggae bass;

- a club dance vibe.

 

In such cases having the right kit to deliver a big low end, without it just being mud, is going to be key and typically is going involve decent sub-woofer(s) added to the tops. Beyond what my lot currently has in terms of kit, but we recently went through a pair of RCF 15" subs plus high quality tops at a function where we were sharing the PA kit of a pro DJ, and it was such a good sound! 

And still the misconception lives.

 

Fundamental frequencies are seldom produced by the subs in professional application. The -10dB sensitivity point on the RCF might be 30hz. To make 30hz as loud as 80hz would take 10x the amount of power. So no point in trying, either the whole system has to be throttled back or the subs get given death by the low EQ being goosed.

 

I have given a club owner a proper fright with my highpassed system being sound checked with a keyboard powering up on 11. Oops. I don't remember if he didn't want the synth psychedelic metal band anywhere near his PA or the band knew mine was better for purpose but I got the call.

 

The club had more subs than me but maybe they hadn't been properly high passed.

 

Put the big energy into 60 to 90hz. WHOMP! Sure gave the guy a fright.

[Paul S]

This is all very interesting.  I am a died in the wool technophobe - my brain is wired in other ways - so please forgive an elementary question. 

 

My band uses a Soundcraft Signature 22 desk and the channel I go through has a HPF button.  Would this do the same thing?  Ditto kick drum.

[Al Krow]

6 minutes ago, Paul S said:

This is all very interesting.  I am a died in the wool technophobe - my brain is wired in other ways - so please forgive an elementary question. 

 

My band uses a Soundcraft Signature 22 desk and the channel I go through has a HPF button.  Would this do the same thing?  Ditto kick drum.

Hi Paul - in short, yes. We have a Soundcraft Signature 12MTK and the hpf kicks in at 100Hz.

We've got hpf engaged for all the channels, including bass, apart from the kick drum which has key frequencies in the 50Hz to 80Hz range and is not being hpf'd. 

[Al Krow]

@Paul S actually I think you've just saved me £93 on getting that excellent looking Sine Effect H24 by reminding me that we've already got hpf sorted via our Soundtrack desk and I can also take the hpf off on my Zoom B1-4 gigging patches and just leave a few on for home use. That's a nice start to the day! 😊