I got this pedal along with the Mini Wah pedal. I was trying to get the Jerry Garcia sound he had often with his Tiger guitar. After playing around with the settings I was really, really pleased with the sound. I am using a Bugera tube amp and two single 12" cabs. Sounds very cool when used together and really gets close to Jerry's sound back then. Thought it was pretty easy to dial both of them in.

This little Donner Digital Octave Guitar Effect Pedal does everything I hoped it would and does it better than I could have expected.
I am not doing any preforming or even recording, just working off stress with an acoustic/electric Ovation, Fender Acoustic Amp, TC Ditto Looper and this octave/detuner/harmonizer pedal.

The pedal can change the pitch of a note by 2, 3, 4, 5, 7, 12 or 24 half-steps up or down. It can also detune by increments of partial steps. Separate pots allow blending of the processed (wet) and unprocessed (dry) signals.

There are combinations of switches, dials and volumes that make weird noises but here are, for me, the most useful settings when coupled with a standard 6-string guitar:

Bass Guitar: Selecting "Flat" on the switch, "1 Oct" on the dial, and turn the Dry volume down to zero.

8-String Bass: Same as bass guitar but add some Dry volume.

12-String Guitar (mostly): Sharp, "1 Oct", and Balanced Wet and Dry volumes. This isn't quite a 12-string because a real 12-string duplicates the B and high E strings where this box increases these strings by an octave too. The EADG strings are like a 12-string.

Lead Guitar: Detune on the switch, "±5" on the dial and a blend of wet and dry volumes. This makes a nice thick note.

Lyricon: Sharp, "2 Oct", Dry volume to zero. Wyndham Hill's Chuck Greenberg used to play a very high-pitched woodwind instrument called a Lyricon. The Donner does a good job of copying this sound with these settings. When played from an acoustic the live sound may drown out the output of the Donner but when looped or recorded it sounds great to me.

The Donner Harmonic Pedal is a winner, especially at this price. Though the basic pedal function is a pitch shifting pedal meaning depending on where you set the middle knob and the toggle switch you can get your standard pitch plus an octave above or below in addition semitones above or below. The wet signal (octave) level can be adjusted as well as the dry guitar signal. This pedal is what I would describe as application specific in other words used on its own it might be too dissonant for most situations.
In this demo/review I have attempted to show some possible uses but certainly not all of how it could be utilized. Tone being a goal of most guitarists; in that our basic tonal personality can easily be hijacked by a unusual sounding pedal, blending dissonance with your basic sound (tone) can add a dimension to your musical impact.
This is not a substitute for lower register or higher register instruments but can be used effectively by carefully blending the sounds into your own take on something or just be an inspiration to create around the new found sounds. The video accompanying this review seeks to show you just some of the possibilities.
Lastly thanks to Shaggy's in Cat City, to RV Velasco for his technical genius and moral support ,to our dogs for adding interest and lastly to Donner for making this all possible. Check out the pedal on the link below. Thanks againDonner Digital Octave Guitar Effect Pedal Harmonic Square 7 modes

Sweet little pedal! Very good quality and sound for money. I think this is a better investment than a pitchfork unless you're a full time musician. It might not hold up to road as well as a more expensive pedal. For the occasional gig & studio musician, it's a knock out.

Lots of fun to be had with this. The tracking is good, even with chords (although they can get a bit muddy if you have in effect 12 different notes piled up. The two octave up (24 semitones) option does a decent organ sound. The detune options include some surprisingly tasty chorus effects, as well as properly detuned. Adding a fourth or fifth below or above tracks well, and doesn't sound half bad, although it's clearly synthetic. Unless you have the cash for a rack harmonizer or one of the pedals out there that approximates that technology, this will handle most of what you need in terms of pitch effects (apart from diving: no input for an expression pedal"”you'll need something like the EHX Pitchfork for that).