Donner Harmonic Square Review

Donner is a very new brand, established only in 2012 and produces musical instruments like ukulele, guitar, mandolin, drum, electric piano, amplifier and guitar effect pedal. Donner Harmonic Square is a very affordable, compact and durable pitch shifter / octave pedal. It is ideally suited for you, if you are just starting to use this effect with your standard electric 6 string guitar or 4 string bass bass guitar. Other than guitars, it works nicely with baritone 6, Yamaha keyboard, vocals/mic etc.

Octave pedals (OP) provide tones that are octaves above or below the frequency of guitar being played and pitch shifting effects. Use of octave pedals gives a funky guitar shedding sound. Jimi Hendrix was among the initial musicians to deploy the octave effect in his performances and recordings.

Octave effects work by mixing (also known as blending) the original signal with a synthesized signal that is one or multiple octaves higher or lower than the input signal. Adding lower octaves will fatten up riffs while introducing higher octaves can give a sizzling effect. You can even remove the original signal completely. Dropping the signal down by octaves will make your instrument sound like a bass.

Things to Consider before purchasing an Octave Pedal

Octave pedals available in the market have differences in ranges, number of frequencies processed simultaneously, analog or digital technology. Before deciding which type of pedal is right for you, you have to keep the following things in mind:

  • Monophonic or Polyphonic? -  Monophonic pedals apply the effects on a single frequency at any given point of time. Traditionally these pedals were monophonic. With technology advancement internal processing units in current times, many manufacturers now provide quality polyphonic effect instruments.
  • Analog or Digital? - Digital pedals can operate on multiple frequencies simultaneously as against analog ones that process one frequency at a time. Digital effects can track the played frequency more closely and produce effects much closer to this input frequency.
  • Where do you want to use them?  - Guitar players commonly use them while playing solos. Other settings are when the player wants to provide unique sound, use higher frequency range or go to mid - bass frequencies. They add flexibility and allow you to be creative in your music.
  • Range ? - Modern octave pedals have the capability to synthesize tones that are 3 octaves away from the input signals. You need to make up your mind what is the range you want from your pedal.
  • Playability & ruggedness? - You want your pedals to be very rugged, sturdy, light weight, portable & smaller in size to occupy less space on your pedal board. Also a lesser number of knobs with simple operation are a great asset for live performances. In studio environments, however, complicated models may be preferred to experiment with different sounds.

Our Picks for Review







Harmonic Square

Donner Harmonic Square 7

PRO's & CON's of Donner Harmonic Square 7

Before we take a deep dive into the features, benefits and  review of Donner Octave Pedal, let us have a look at some of its pro's and con's.


  • It comes with a minimal number of easy to use knobs and handy LED indicators to enhance playability.
  • It is incredibly affordable given its flexibility and versatility.
  • It has great tracking, low noise level and a very wide range of sonic effects with internal harmony.


  • It requires a DC 9V power supply to operate, but the pedal does not come with a power supply. Cannot operate it with batteries.
  • It may not last as long as some of the expensive models.
  • Some players consider the sound to be a bit synthetic.

Features and Benefits

In this section, let us look at the features and benefits of Donner Harmonic Square (a.k.a Harmonic Square 7). These features and functionalities include various modes, how to select between different modes, how sound output differs with the modes, true bypass, wet and dry signals, pitch shifter etc.

Features of Donner Harmonic Guitar Pedal

Some of the important features of Donner Harmonic Square 7 modes are:

  1. 1
    Harmonic Square 7 is a digital circuit pedal. Hence, it is also referred to in some literature as Donner Digital Octave.
  2. 2
    It has 3 basic modes of operation - Sharp, Detune & Flat. They work in conjunction with pitch shifter dial to alter the pitch of the guitar signal.
  3. 3
    Donner Digital Octave is also called Harmonic Square 7, as it has 7 modes to select from. These 7 octave modes include ±2, ±3, ±4, ±5, ±7, 1 octave and 2 octaves. This means that you can go down or up by 2, 3, 4, 5, and 7 semitones and by 1 or 2 octaves. Some players, specially bassists, consider these mode options to be more than what they can use.  Others find them perfectly usable.
  4. 4
    It is possible to control the level of the harmonic signal, as well as the dry signal. Harmonic signal is also called the wet signal and is the synthesized signal, whereas, the dry signal is the original input signal from the guitar.
  5. 5
    In many situations, you would like your input signal to pass through the pedal without any processing, which effectively means that the pedal is disengaged. This is where the true bypass feature comes into play.
  6. 6
    Its small sized enclosure (95 x 45 x 48) mm is lightweight (250 g) and can fit in even in the most crowded of pedal boards. Its lightweight results in the benefit of portability.
  7. 7
    It is housed in an Aluminium alloy enclosure that is stable, strong and rugged.
  8. 8
    The negative side of any small sized enclosure is that manufacturers have to leave certain components, which takes more space. Here, battery is the casualty.  Donner digital octave pedal works on Dc 9V power supply and takes about 110 mA current. This DC 9V power supply adapter is not part of the pedal deliverables and has to be purchased separately.
  9. 9
    The pedal has one input and one output jack for input and output signals. Both are 1/4" Monaural jacks.

Controls On Harmonic Square 7

You would expect much less control functions on tiny pedals. To your pleasant surprise, you will find that Harmonic Square 7 has all the controls functions that you will need to control the output tone. It achieves these controls through 3 knobs, a toggle switch  and a foot switch and allows you to modify all the basic parameters. Let us have a look at these controls :

  1. 1
    Wet and Dry Control knobs allow you to control the volume of harmonic signal and the dry signal respectively.
  2. 2
    Three way toggle switch allows due to select between different modes of operation from Sharp, Detune & Flat. Once you have selected one of the modes, let us say sharp, the settings of wet and dry knobs will determine how sharp your tone is in comparison to the natural one.
  3. 3
    The bigger dial knob in the center of Harmonic Square allows you to raise or lower the signal by 2, 3, 4, 5, 7, 12 and 24 semitones. This selection, together with toggle switch and wet / dry knobs defines the overall effect your pedal will produce.
  4. 4
    LED indicator tells you about the working state of the effect pedal.
  5. 5
    True Bypass: You can activate or deactivate the effect unit with the press of the true bypass foot switch. It is a simple on / off switch, which will allow the original signal to simply pass through when the unit is deactivated.


Donner digital octave combines pitch shifting and octave effects and can be used with both bass and guitar. The below video shows the sounds produced in the entire matrix of 7 octave modes by 3 operation modes. It will give you the feel of the capabilities of the pedal in all common settings. You may not ordinarily use all the settings, but choices are there to experiment.

  1. 1
    For any pitch shifting / octave pedals to work like true magic, the unit must have the ability to accurately detect the input signal continuously. Tracking ability of the unit is remarkable, allowing the output signals to be always in sync with the signals from your instrument. The feature is particularly important for the low end.
  2. 2
    While you can go even two octaves up with the unit, it is not recommended for the bass, as the entire low end will be sacrificed.
  3. 3
    ou can detune and select the degree of detuning by selecting the Detune mode and various settings of the pitch selector.

Social Proof of the pedal

Before committing yourself to purchase any pedals, it is always a good idea to scan the web for reviews from the players who have used it previously. To help you through the process, we have included some reviews along with our views on the same.

Donner Harmonic Square Review 01

The reviewer points out that if you do not frequently use octave pedals and are looking for specific sound requirements, this one is a great choice given its low price. He also appreciates its smaller size, light weight and ruggedness.

Donner Harmonic Square Review 02

The reviewer is impressed with the quality of Donner and talks at length about the various functionality and features of this model and how he uses it. In addition, he talks about form, price, fast delivery and rugged nature of the pedal.

Donner Harmonic Square Review 03

The user is appreciative of the single effect pedals from Donner, but expresses his reservations of the output from the multi effect pedals from them and their versatility.

In Conclusion

Donner Harmonic Square provides octave and pitch shifting effects with several octave range and harmony settings. It is a great option for both guitarists and bass players looking to go to low or high range frequencies. It has three different modes of operation and a selection of 7 variables. It has a three way toggle switch to change the modes and comes with DRY and WET knobs to vary the harmonic levels.

It has a compact & portable size, strong metallic body and a very affordable price. Its lower price level may even dissuade some of the potential buyers, who equate price to quality.  Don't let its price fool you. Its versatility makes it a pedal you will love to check out!

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