Make Your Harmonica Sound HUGE (with an Octave Pedal)
If you’ve begun to play with a microphone, here’s a secret to making you sound 10X bigger. Just step on a pedal…
There are a few electric-guitar-style effect pedals that are especially well suited to the harmonica, and one of them is the octave pedal.
This pedal works by capturing the sound of the instrument and creating a synthesized pitch an octave apart that sounds at the same time.
The way we harmonica players mostly like to use this pedal is to produce a pitch ONE OCTAVE BELOW the harmonica, which creates a huge fat tone. Some pedals also can create a sound -2 octaves, +1 octave, +2 octaves, but the most common sound is the dry signal plus a sound one octave below it (-1 octave).
Sax players have been doing this for decades, ever since Eddie Harris first recorded the sound in 1967 on the Electrifying Eddie Harris (you can check that out here).
I’m shooting out 4 octave Pedals for you to consider. In my shootout videos I’m using a Jason Ricci signature mic into a Pignose Hog20 amp (I’ve already written about the amp here).
Even though I’m using this effect in an amplified harmonica (distorted) kind of context, you could also use it in a clean context. (You’d just need a transformer to get the XLR cable attached to the mic to go into the pedal.)
Here’s what I liked and didn’t like about each pedal, along with links to videos to see and hear them in action. Spoiler alert: I think the POG Pico is probably the best bang for the buck.
The Boss OC-5 
($158)
Boss has been making octave pedals for decades, and their current iteration at the time of writing this is the OC-5.
This pedal has a lot of features that can be cool for guitar players, but for harmonica players we’ll always want to:
Have the switch on the front switched to “Poly” (which stands for polyphonic - meaning we can play more than one note at a time and have the pedal function properly)
The knob on the right should be turned up all the way.
These settings 
will allow us to play more than one note at a time, and will ensure that the entire range of the harmonica gets the octave down pitch added to it, and that it tracks well.
What I love about this pedal
The Price! It’s the most affordable option of all the pedals.
The -1 Octave is the fattest (bassiest) of all the pedals.
You can blend the dry harmonica and low octave levels to taste
This is the ONLY pedal that allows you to route the LOW octave to a separate destination. For example, you could route the -1 octave to a bass amp, or a channel on the soundboard that gets routed to a sub so that the low sound blows everyone’s hair back!
Reasonably small footprint.
Also has +1 Octave that you can mix in to taste.
What I don’t love
The low sound might actually be a little too fat? Might not cut as well? POG has more midrange bite that I enjoy hearing.
Tracking is OK in “Poly” but not so great in “Vintage” mode (thus my instructions at the top of this segment.)
No other bells and whistles (chorus, harmonies.)
It’s kinda ugly.
You can hear it in action here:
The Digitech Whammy Pedal DT ($420)
There are 2 versions of the Whammy Pedal. The one I’m using in this shootout is the DT, which stands for “Drop Tuning” because the added right side of the pedal allows guitar players to change key by stepping on the pedal.
The Drop Tuning effect does not track well enough on harmonica to be a practical solution for changing keys.
But the right side of the pedal does work well as an octave pedal, allowing you to use the Whammy side of the pedal for other effects, from subtle chorus, to harmonies, to outlandish whammy effects.
What I like
This pedal sounds great and tracks great.
Extra bells and whistles!
Detune “Chorus” effect for more motion to single notes, and especially chords
Other harmonies are available. 4ths are cool in a funk context, used sparingly.
Whammy effects (only for the bravest explorers!
)
“Momentary” switch also can create wild effects, or allow you to quickly access low pitch for just a few notes
What I don’t like
EXPENSIVE. (Your spouse doesn’t want you to choose this pedal! 
)
HUGE footprint.
NO ability to blend dry signal and low octave signal levels. Both at equal volume, or just low octave without dry signal, but no degrees of variation in between.
You can hear it in action here:
The Electro Harmonix POG2 ($400 )
This is a very robust pedal. Probably more feature-rich than most harmonica players need.
What I like
Great Tone! Something about this pedal just SOUNDS good.
-2 Octave Generator. This is the only pedal of those reviewed that can produce this sound and the dry signal at the same time. Actually a cool sound! (The Whammy pedal can do just -2 Octave without dry on the left side of the pedal.)
You can blend the dry harmonica and low octave levels to taste
Other bells and whistles:
Detune “Chorus” effect for more motion to chords
+1 and +2 Octaves with Detune effect creates an organ-like effect. Remove dry signal and turn up attack slider to increase organ-like sound
What I don’t like
EXPENSIVE. 
(Your spouse doesn’t want you to choose this pedal either! )
BIG footprint.
You can hear it in action here:
POG Pico ($240)
This is one of POG2’s little brothers. Electro Harmonix makes several versions of this pedal, and I think this one is the best for harmonica players.
What I like
The Price - I mean it ain’t cheap, but it’s 40% cheaper than it’s big brother
Great Tone! Something about this pedal just SOUNDS good. Not QUITE as good as its big brother…but it’s dang close!
You can blend the dry harmonica and low octave levels to taste
It’s also got a +1 Octave signal you can blend in to taste.
The SMALLEST footprint of them all.
TONE KNOB - really sets this pedal apart from the Boss OC-5. More control over the overall sound with the tone knob. Electro Harmonix also makes a “POG Micro” for $230 which is identical to this pedal, but lacks the tone knob. Definitely worth an extra $10 for the tone knob!
What I don’t like
No other bells and whistles (chorus, harmonies, -2 Octave of it’s bigger brother.)
You can hear it in action here:
I’d say bang for the buck (assuming you don’t care about bells and whistles) the POG Pico probably wins the battle since it’s so nice and small, RELATIVELY affordable, the smallest footprint, and most importantly SOUNDS AMAZING.