The Sonic Research Turbo Tuner ST-300 Mini is a guitar tuner pedal from Sonic Research, part of the company's range of true stroboscope tuners1. MusicRadar's review credits it with intuitive note detection, naming it as a reason to buy1. It also includes a drop tuning facility that lowers the pitch of all notes below the regular tuning from one to six semitones1. For a player, that means a strobe tuner in a mini enclosure that barely takes up board space, alongside other compact tuners such as the TC Electronic PolyTune 2 Mini or the Peterson StroboStomp Mini.
Six modes and the controls
The ST-300 Mini runs six modes. MusicRadar explains that "of the six modes, chromatic mode displays the pitch of the plucked string"1, with the other modes covering the pedal's remaining display and tuning options. The pedal's drop tuning facility lets you lower the pitch of all notes below the regular tuning from one to six semitones, which suits players who keep a guitar in standard tuning but drop tune for certain songs1.
Guitar Pedal X's buying guide sums up the controls as "6 Modes : Mode - / Mode + hold for Frequency Calibration / Number of Flats"2. In practice:
- Mode - and Mode + step through the six modes.
- Holding Mode + enters Frequency Calibration, where the reference frequency is set.
- Number of Flats sets how far the whole tuning is flattened, working with the drop tuning facility.
MusicRadar's reviewer also lists "intuitive note detection" among the pedal's strengths1.
Where it sits in the Sonic Research range
The ST-300 Mini is the compact version of Sonic Research's ST-300 Turbo Tuner. Players comparing the two should note that MXR collaborated with Sonic Research on the MXR M400 Turbo Tuner, which Guitar Pedal X describes as "Presumably an update and revision of Sonic Research's own ST-300 Turbo Tuner"3.
For more on how strobe tuners differ from the chromatic LED types, see Tuner Pedals.
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Questions
How accurate is the Sonic Research Turbo Tuner ST-300 Mini?
MusicRadar's review, by Trevor Curwen, gives a stated accuracy of 0.02 cents. The ST-300 Mini belongs to Sonic Research's range of true stroboscope tuners, which the same review praises for instant response and extreme accuracy, so it sits among the most precise pedal tuners a player can put on a board.
How big is the ST-300 Mini?
Guitar Pedal X lists its dimensions as 40 x 94 x 30mm, and MusicRadar describes it as a pedal the size of TC's popular PolyTune 2 Mini, so it takes up about as much board space as a standard mini enclosure.
How do you change the reference frequency on the ST-300 Mini?
According to Guitar Pedal X's controls listing, you hold the Mode + button to enter Frequency Calibration. The pedal's two mode buttons, Mode - and Mode +, also step through its six modes, and a separate control sets the number of flats.
What is the MXR M400 Turbo Tuner?
The MXR M400 Turbo Tuner is a collaboration between MXR and Sonic Research. Guitar Pedal X describes it as presumably an update and revision of Sonic Research's own ST-300 Turbo Tuner, and it was on sale and shipping from the Sonic Research webstore at a MAP/RRP of $149.99 as of October 2026.
How much does the ST-300 Mini cost?
Guitar Pedal X's buying guide of 16 June 2025 lists the ST-300 Mini at $139.
Sources (3)
- Sonic Research Turbo Tuner ST-300 Mini review, MusicRadar, 2017-01-17
- Guitar Pedal X, Guitar Pedal X, 2025-06-16
- Guitar Pedal X, Guitar Pedal X, 2026-10-13
