I have been looking at building or purchasing an Octave Down pedal which is simply a frequency divider. The biggest problem that I keep reading about is that they are ok for single notes but not chords and they have a lot of "fuzz" accompanied with them.
This has me wondering if anyone has tried to simply run a guitar signal through a variable high frequency bypass filter (say a 1MFD cap and pot) then run that through a preamp circuit to boost what is left of the signal back up and then to the guitar amp?
This would give a true frequency just without anything above say 400hz. It would not affect the chords like dividing frequencies does. Would it?
Is this feasible? Has anyone tried it?
This has me wondering if anyone has tried to simply run a guitar signal through a variable high frequency bypass filter (say a 1MFD cap and pot) then run that through a preamp circuit to boost what is left of the signal back up and then to the guitar amp?
This would give a true frequency just without anything above say 400hz. It would not affect the chords like dividing frequencies does. Would it?
Is this feasible? Has anyone tried it?
Got an FX loop? Get a 31 band graphic EQ and insert it there. Now you can make up a pass filter for whatever freqs you like. Close enough for experiments. I don't think it will work like you imagine though.
It will give you the true frequency, yes: the original ones present.
It will not create an octave down.
An octave down pedal often is a flip-flop circuit that creates a pulse an octave lower than the input. This can then be low-passed to make less harmonics.
This is a great one.
The Valve Wizard
But they only work as expected with single notes.
An other alternative would be a pitch shifter.
These do work with chords, but have a slight delay.
I like this for my bass playing as it can easily go to 40Hz and lower. The delay doesn't bother me, as the attack part of the sound doesn't have much frequency info in it. I have one of those Behringer multi fx stomp-boxes for this, it sounds bad but in a really good way. And is cheap as dirt.
This is a great one.
The Valve Wizard
But they only work as expected with single notes.
An other alternative would be a pitch shifter.
These do work with chords, but have a slight delay.
I like this for my bass playing as it can easily go to 40Hz and lower. The delay doesn't bother me, as the attack part of the sound doesn't have much frequency info in it. I have one of those Behringer multi fx stomp-boxes for this, it sounds bad but in a really good way. And is cheap as dirt.
As said, filtering alone does not create a subharmonic.
The frequency division is the easy part. Detecting the fundamental from complex signal with highly varying dynamics and envelope is where making a "well-mannered" octave down effect gets challenging.
The frequency division is the easy part. Detecting the fundamental from complex signal with highly varying dynamics and envelope is where making a "well-mannered" octave down effect gets challenging.
The octave down is usually done digitall using a div 2 circuit like a D type flip flop or you can use a counter to provide /2 /4 /8 etc etc
I would recommend a Zoom 707 effects pedal which does just about anything you could wish for. Its 25 years since I bought mine but I think they do come up on ebay now and then.
I would recommend a Zoom 707 effects pedal which does just about anything you could wish for. Its 25 years since I bought mine but I think they do come up on ebay now and then.
AFAIK from reading instrument forums the POG family are the only effects boxes that can do polyphonic octave effects cleanly.
Like this. Ashdown Sub-Octave Plus Distortion Bass Effects Pedal - Woodwind & Brasswind
Top right corner shows the circuit but the IC is xed out.
ashdown abm 500 schematic - Google Search
Top right corner shows the circuit but the IC is xed out.
ashdown abm 500 schematic - Google Search
Unless getting extremely complex, most just feature the Boss OC-2 circuit with perhaps slight modifications. Not a joke.
Can't recall what the Ashdown IC was (its shown in earlier schematic revision IIRC) but I recall it was just an integrated package of separate MOSFETs and otherwise the octaver was pretty much standard "OC-2" circuit.
Can't recall what the Ashdown IC was (its shown in earlier schematic revision IIRC) but I recall it was just an integrated package of separate MOSFETs and otherwise the octaver was pretty much standard "OC-2" circuit.
Interesting request. The Electro Harmonix Micro POG has some pretty good reviews on Amzn, but it'll set you back a couple of hundred. I cant find how it works - anywhere. After hearing what it can do for a violin, I wouldnt bother with flip flops, PLLs or VOGs; get something that does just what you want with no caveats.
My memory fails me. The chip is Mitsubishi's M51134 Sub-harmonizer. SWR amps had the aforementioned integrated Mosfet package.