Using an octave pedal before an HPF pedal?

[TaylorJ]

I’m considering adding an octave pedal to my board. At the moment the last pedal in the pedal sequence is a Thumpinator. The Thumpinator specs are:

Cut-off frequency: ~25Hz
Slope: 36 dB/oct

Will the Thumpinator just negate the effects of the octave pedal? Do I need to remove the Thumpinator to get the most out of the octave pedal? Or will it even matter?

JT

 

[darev]

The Thumpinator is probably located in a great place. The Thumpinator only cuts the infrasonics (the lows that cannot be heard by the ears but are reproduced by amp and the speakers) not the audible lows.

In my opinion, the octave pedal is likely generating a whole bunch of more of the infrasonics and the Thumpinator at the end would help to protect your amp and speakers.

 

[kleinenenten]

I used to have (and recently re-purchased and am awaiting delivery of) an MXR Bass Octave Deluxe. I always have an FDeck V3 in my amp's FX loop. The previous post is exactly my experience. I could certainly hear the octave working as intended, and I'd push massive, audible lows in the process. But it also kept my speakers and my amp's power amp safe from trying to reproduce excessive lows that can't be heard anyway. I always use an HPF for speaker protection and to keep my amp from having to try and reproduce frequencies we can't hear, which in turn keeps it running more efficiently and seemingly slightly louder and cleaner.

TL;DR - the HPF should NOT negate the octave, but WILL protect your setup.

 

[TaylorJ]

Perfect, thanks for the information!

 

[JamesGrant]

I have a not particularly subby jazz bass. My 1st pedal is a HPF which seems to clean up the sound and helps the pedals/fx that do tracking to track well. My last ‘thing’ is the HPF on the amp input. So I do both! I use a -1 with a splash of -2 octave effect on a few tunes and the effect works great!

 

[5stringwonder]

The Thumpinator is probably located in a great place. The Thumpinator only cuts the infrasonics (the lows that cannot be heard by the ears but are reproduced by amp and the speakers) not the audible lows.

In my opinion, the octave pedal is likely generating a whole bunch of more of the infrasonics and the Thumpinator at the end would help to protect your amp and speakers.

Had the understanding that the ideal place for the Thumpinator is at the start of the chain? Would it work better at the end?

 

[micguy]

The Thumpinator is probably located in a great place. The Thumpinator only cuts the infrasonics (the lows that cannot be heard by the ears but are reproduced by amp and the speakers) not the audible lows.

In my opinion, the octave pedal is likely generating a whole bunch of more of the infrasonics and the Thumpinator at the end would help to protect your amp and speakers.

I came into this thread to post...the above. Well said, i second this.

 

[UntitledProject]

Dusty Hill used this exact setup on his touring rig.

 

[piertbone]

Pretty common to have a HPF after your octave, especially if it's a suboctave like the Meatbox or Mantic Hulk. Even with those you don't need the sub 25 Hz range, only thing that range does is muddy your sound and potentially damage your amp.

I have a not particularly subby jazz bass. My 1st pedal is a HPF which seems to clean up the sound and helps the pedals/fx that do tracking to track well. My last ‘thing’ is the HPF on the amp input. So I do both! I use a -1 with a splash of -2 octave effect on a few tunes and the effect works great!

Good point as well. I actually do the opposite; because my sousaphone produces a solid amount of high(er) frequencies it sometimes makes tracking for octaves more difficult, especially on analogue octaves. Whenever I use my analogue octave I run my Source Audio EQ2 twice in the chain, first as a LPF to get rid of the higher frequencies and after the Cog T47 as a HPF to clear up the sound.

 

[RattleSnack]

Yup, HPF (or low cut filter) goes last ideally. Octaver only benefits from it, as properly set HPF "tightens it up".
E.g. I don't use it as a pedal, but on a mixer board.

 

[darev]

In this instance we are talking about a Thumpinator that has a slope of 36dB/Oct! not a first or second order HPF. This is an extreme slope that you won't typically find in a Broughton or the like HPF. The Thumpinator uses a 6th order slope

Had the understanding that the ideal place for the Thumpinator is at the start of the chain? Would it work better at the end?

A Thumpinator can be run anywhere but they do say start in the front.

In the use case that was presented to us: Thumpinator is at the end already with an octaver in place. If the Thumpinator is in front then all of the new infrasonics created by the octaver will go right to the amp/speakers and the Thumpinator will not be able to clan up the newly created noise.

 

[rcmbass]

I have the Thumpinator at the front of my signal chain. I then run into a tuner/buffer, then into two octave pedals, the MXR Vintage Bass Octave and the MXR Bass Synth. I find that both of these octave pedals track better with the Thumpinator at the front of the chain.

I run 100% in ear monitors (IEM) in all of my playing except for my home studio.

Are some of you suggesting I use a high pass filter at the end of my signal chain/after octave pedals to protect amps and speakers?

If so, I assume I can run a HPF from my HX Stomp which is at the end of my signal chain. Would that do it?

 

[Zooberwerx]

I have the Thumpinator at the front of my signal chain. I then run into a tuner/buffer, then into two octave pedals, the MXR Vintage Bass Octave and the MXR Bass Synth. I find that both of these octave pedals track better with the Thumpinator at the front of the chain.

I run 100% in ear monitors (IEM) in all of my playing except for my home studio.

Are some of you suggesting I use a high pass filter at the end of my signal chain/after octave pedals to protect amps and speakers?

If so, I assume I can run a HPF from my HX Stomp which is at the end of my signal chain. Would that do it?

I, too, was of the impression that a judiciously-applied HPF would benefit octave triggering & tracking downstream.

Riis

 

[Wasnex]

I skimmed through the responses and I don't think anyone said it directly.

Most likely your speaker can't produce the frequencies the Thumpinator is filtering out. Most bass cabs are not even flat to 41.2 hz (fundamental of the low E string).

Driver excursion in ported cabs tends to have sort of an S-shape. As the frequency drops below about 500hz, excursion starts to increase. At some point the woofer will begin to cut off. The port is tuned to start becoming active when this occurs. As the frequency continues to drop, the port becomes more active, which suppresses cone excursion. At the tuning frequency (Fb), the port is providing most of the speaker system's output and maximum suppression to cone excursion. As the frequency drops below Fb, system output drops quickly and driver excursion increases quickly.

There is little point in operating the system very far below Fb. The system is incapable of significant output and driver damage from over excursion happens at a much lower power level.

Here is a graph showing the LF response of the fEARless line. These cabs were noted for having strong and extended LF response.

The 12" designs use an Eminence 3012LF. Eminence publishes cab design docs for this driver.

This is from the large vented design...I think this curve is the closest to the Greenboy curve above...similar but probably not exact.

The eminence notes for this design say: "400 Watts; F3 of 46 Hz, F10 of 35 Hz. High pass at 30 Hz."

FYI, F3 is the point where response has dropped 3dB. F10 is the point where response is down 10dB. -10dB is typically considered the limit of usable response. I suspect the HPF should probably be set a little higher than 30hz since the driver exceeds Xmax in the mid-30hz range with 400W.

Here is the excursion plot for this design:

Note that Xmax for the 3012LF is 9.1mm. The trace in this curve turns from black to gray when the driver hits Xmax in the mid 40hz range. Note the tuning frequency (Fb) is 44hz. As you see the dip in the excursion plot is centered at 44hz.

Take a look at both plots and note how quickly response is dropping below 44hz and also how quickly excursion is increasing.

 

[darev]

Thanks for the information @Wasnex

 

[JamesGrant]

I’ve said this before but…. I used to play a Warwick thumb 5 string and a Warwick Streamer LX into and Ephiani amp and cabs (2 x 10inch). Even at low volumes, I could *see* the cones oscillating at very low frequencies. There was no HPF on the amp, and I didn’t (yet) have a pedal to deal with infrasonics. I bought a Boughton HPF pedal and didn’t notice any difference in sound but (unsurprisingly in retrospect) I was able to get a much louder volume from my rig before the speakers ‘bottomed out’ (where the tube that the coil is wound on hits the back of the magnet enclosure - it sounds very unpleasant). When using the HPF pedal I couldn’t see the cones ‘wondering’ either.
Since then I’ve been an ‘always on’ HPF aficionado. Always good to have a on/off and a frequency selector to clearly hear the difference (or set it so there’s no practical difference).

 

[rcmbass]

 

[WaldoNova]

I run my EQ2 at the front of my chain,1st pedal. It has a HPF. When I use an octave it glitches less frequently and tracks excellently. I like how the octave sounds when it hits my Finally. Which is my DI. I run IEM's every time I perform and FOH has a HPF at the board.

I'd probably approach it differently if I was running into an amp.

 

[mouthmw]

In this instance we are talking about a Thumpinator that has a slope of 36dB/Oct! not a first or second order HPF. This is an extreme slope that you won't typically find in a Broughton or the like HPF. The Thumpinator uses a 6th order slope

Sure, but by the “time” (octave) my Broughton HPF reaches the low 25 Hz that Thumpinator is set at - it reduces plenty with the second order slope because I have it set at 80 Hz where it does more for me than just get rid of inaudible rumble.

So that would be:
-3 dB at the cutoff point (80 Hz)
-15 dB at 40 Hz
-27 dB at 20 Hz
-39 dB at 10 Hz
And so on. But my Broughton BBA pretty much already annihilates anything below 20 Hz (probably a more comparable pedal to Thumpinator).
Thumpinator would be -36 dB once it reaches 12.5 Hz.

To OP - I have zero issues with my Octaver when using both BBA before it and HPF after it.

 

[RestlessBoom]

Just do the proper thing and put the Thumpinator first in the chain. Why do anything else?