HPFs and the Low B-String Fundamental

[fu22ba55]

Ready to jump on the HPF bandwagon on electric after using one a fair amount with Double Bass.

I'm assuming no cabs can truly reproduce the 31 Hz fundamental? Is that correct? I'm using two Fearful 15/6s and they start rolling off at 45 Hz. Am I even hearing the 31 Hz fundamental or only the 62 Hz overtone?

My issue is this: my FDeck HPF bottoms out at 35Hz, and I'm currently in a project that's using the low B a LOT.

I assume HPFs are usually a slope.. not a hard cliff... but should I look for a different HPF that goes as low as 30Hz to accomodate the B-string's fundamental? Or is it pointless to try and reproduce, and I can just use a 35Hz HPF?

I can't seem to find ANY HPFs (Broughton) for sale anywhere... unobtainium. But there's this little guy all over Reverb that goes down to 20 Hz:

Chaos Custom Shop

 

[31HZ]

No cabs will reproduce the 31Hz fundamental without substantial rolloff, and many (if not most) adults can't hear that frequency.

You're hearing the overtones.

Source: I use the open B not infrequently, and as a soundman I run HPFs above 31Hz on my sub arrays ... and my user name checks out

 

[gidbass]

I use the Broughton always on one. No markings on the dial, but I just use my ears to set it .

Always On High Pass Filter | Broughton Audio

A standard Broughton high pass filter with the bypass switch removed. This design allows a more compact layout, fitting on a single pedal board rail, or even mountable underneath a pedal board. The high pass filter is a 12 dB per octave low frequency filter. The knob controls the cutoff...

www.broughtonaudio.com

Good Luck!

 

[J Wilson]

The 'low B you hear' is actually the stacking harmonics at 63hz, 126, 252, and on up the line.

You could make that fundamental with some serious home hi-fi, but in live music, to push it would take some of those multi-18 forklift-only subwoofers at the bottom of a big FOH touring sound system.

 

[S-Bigbottom]

I high pass at 60hz and with a little bump from the Bass knob I can shake the fillings out of your teeth.

You do not need the 30hz range. Use your FDeck and your EQ.

 

[micguy]

No bass guitar cabs will reproduce the fundamentals of a low B, but…if you play ampless gigs through very capable PA’s with the “big boy” subs (hint - those won’t fit in your car), those WILL reproduce the fundamental of a low B just fine. I get to play places with PA’s of that caliber on a regular basis, and the difference between a 5 through one of those vs any bass amp rig is NOT subtle.

 

[packhowitzer]

I play a 5-string NS Design CR5 radius with a 35" scale. It has a thunderous B string - especially the low D and C. I use a Broughton HPF with the cutoff set at about 40Hz-ish. And any of the notes I play on the B string will rip your guts out. In fact, using the HPF tightens up the perceived sound tremendously IMO. I play live about 60 times a year and will never be without that HPF in my signal chain.

 

[Thumpin6string]

No problems with my low B on both of my 6 strings using my Broughton always on HPF. I can shake the furniture across the floor with my low B with HPF at about 40HZ.

 

[logdrum]

It's not a brick wall at 35 Hz, If the slope says it is 12Db per Octave that means that it will cut it by 12Db at t 17.5 Hz which is below human hearing ( Young children may be able to hear 20 Hz -- dogs too ), So without a calculator assuming that is a linear slope, Yeah if your sub array and amplifier can indeed amplify and reproduce 31Hz, it's only 2 dB or so of reduction. That is a lot of low end. I do think bass guitars and pickups however good cannot compete with a bass synth. But even there, it is more effective to use a saw or square wave oscillator which has richer harmonics than say a triangle or sine wave. No EDM synth person would use use those oscillators solely for low end. Undefined however good your PA is, HPF is also for improving bass efficiency and tightness.


Do not worry if you do not have these high end Meyers or whatever these uber expensive subs are called. The human brain will fill in the blanks even if it's the 62 Hz they are hearing primarily

 

[fishdude101101]

Its a rolloff not an elimination. Large scale pa its more of a feel than hear thing.

 

[agedhorse]

Too much of the extreme low end can really ruin a mix in a hurry, especially in a large, live room.

 

[DJ Bebop]

No bass guitar cabs will reproduce the fundamentals of a low B, but…if you play ampless gigs through very capable PA’s with the “big boy” subs (hint - those won’t fit in your car), those WILL reproduce the fundamental of a low B just fine. I get to play places with PA’s of that caliber on a regular basis, and the difference between a 5 through one of those vs any bass amp rig is NOT subtle.

And I love that!

One of my favorite places to play had just that kind of PA. I could sit out in the audience while playing our set. I would also heckled the band from there Anyway, that was the best my bass and playing sounded
It was like being John Entwistle, Bootsy Collins, or something

 

[Wasnex]

Ported cabs should not be operated very far below their tuning frequency (Fb).

Here are some plots for a medium ported design using the 3012LF.

The design is mechanically limited to 400W and an HPF is recommended at 30hz to protect the driver. Response is down -3dB at 55hz and the system tuning (Fb) is 44hz.

Notice there is a dip in woofer excursion at Fb = 44hz. As the frequency drops below Fb, excursion increase quickly and response drops off. Xmax occurs with 400W at about 35hz. AFAIK most Eminence cab designs recommend setting the HPF to the frequency were excursion equals Xmax at rated power. When an HPF is set to 35hz, it means the response is being attenuated by 3dB.

IMHO there is not much point in sending 30hz to this cab as response appears to be down by 15dB at 30z. Usable response (-10dB) only goes down slightly below 40hz.

 

[winegamd]

The HPF should be set for the protection of the enclosure and/or to tighten the tone. Setting it at 31hz is not the most efficient use of the filter. For example, looking at the tuning and excursion plot above, I would probably set it to about 40-42hz (to start) for that enclosure. That would keep the driver at max or less as the freq dropped below for.

To simplify, the HPF should be set to the tuning freq of the enclosure (or maybe few hz lower) at the min, then raised higher to tighten the low end in a boom room. It normally shouldn't be set lower than the cab's fs, as that defeats the purpose.

 

[darwin-bass]

I recently got a mid range 5 string. Lowest notes sounded a bit loud and dull. I brought up the cutoff frequency on my HPF and the B string cleaned up, sounding more matched with the other strings.

 

[getBAK]

I've never heard of Chaos as a brand, but that doesn't mean they are bad. Most 'pedals' use the same circuits regardless of manufacturer. It's more about quality control than anything. That said, I can't think of any reason to have a 20hz HPF.

RE Availability

Broughton shows the HPF for sale on their page.

High Pass Filter | Broughton Audio

The High Pass Filter is the perfect utility pedal for cleaning up the low end. The high pass filter is a 12 dB per octave low frequency filter. The knob controls the cutoff frequency and ranges continuously from 25 Hz to 190 Hz. The stock input impedance is 1MΩ. If you have an acoustic pickup...

www.broughtonaudio.com

Josh is very good about taking things down that are unavailable

F-Deck is also showing available - don't be intimidated by the website, they are legit.

hpftechllc - About HPF-Pre

Site updated: Oct. 18, 2024 Status: HPF-Pre is ready to take your orders! Announcement: HPF-Pre Series 3 Mini is now available! Series 3 Mini is the answer to many requests that I've received over the years. Bassists have asked me about a layout similar to most guitar and bass effects pedals. It's

sites.google.com

The SFX MicroThumpinator is also available (ZZ Top approved)

[sfx] sfx sound: micro-Thumpinator v2

High performance audio devices

www.sfxsound.co.uk

If you want something more expansive, the Genzler Re-Q and Magellen both have HPF's built in

https://genzleramplification.com/product-category/pedals/

 

[Jazzdogg]

Too much of the extreme low end can really ruin a mix in a hurry, especially in a large, live room.

The majority of the live music I've heard in the past few decades has been ruined by FOH overusing subs.

 

[dbflats]

I love low-end content. Hey I'm a bass player! But totally agree with above statement, too many sound engineers abusing the overall mix with too much sub low.

Speaking of the Broughton Always On, anyone know what frequency you're aiming at when you point the dial right at the light?

 

[agedhorse]

Low frequency extension done well and tastefully is great, but that takes good understanding of how to mix for the "greater good", common sense, and the ability to use good judgement when rooms get tough.

 

[scott sinner]

No cabs will reproduce the 31Hz fundamental without substantial rolloff, and many (if not most) adults can't hear that frequency.

You're hearing the overtones.

Source: I use the open B not infrequently, and as a soundman I run HPFs above 31Hz on my sub arrays ... and my user name checks out

This. I've experimented with this a little as I have a Broughton variable HPF. A 30Hz HPF usually means that is where the slope starts. I've found I can't hear a useful difference in the fundamental of the B until I get to like 50 with a nice big 15 inch speaker. Like, can I notice it before that, yes, but we're talking a volume difference of the tiniest increment on the ppp to fff I could manage with my fingers.

What I feel on the other hand even dialing it up, is a reduction in muddy resonances and feedback with the drums I don't want.

So I have mine set at 40.