The Behringer B-Tron III is a vintage-style auto-wah envelope filter pedal that creates a wah or vowel sound every time you play a note. Instead of rocking a foot pedal like a traditional wah, the filter responds to your picking dynamics: play harder and the filter sweeps further, play softly and it barely moves. Behringer says it works great for bringing the funk with guitar, bass or keyboards1.
The pedal is a revival of a circuit that shaped 1970s music. MusicRadar's Jonathan Horsley described it as "an homage to the Mu-Tron III", the classic envelope filter made by Musitronics2.
What it does and how it is controlled
An envelope filter follows the shape of your note, the envelope, and uses it to sweep a filter up or down in frequency. The B-Tron III gives you three switches to shape that sweep12:
| Control | Settings | What it does |
|---|---|---|
| Mode | Low Pass, Band Pass, High Pass | Selects the filter type; Behringer says the settings deliver "a nice quack"1 |
| Drive | Up, Down | Sets the sweep direction, for a traditional wah sound or a cocked wow sound1 |
| Range | Low, High | Low gives more vowel-like sounds; high emphasizes more overtones1 |
The Mode switch is a three-way selector offering low-pass, band-pass or high-pass filtering2. The Drive switch determines whether the filter sweeps upward or downward as you dig in, which is the difference between the familiar wah quack and the "cocked wow" sound of a wah pedal parked in one position1. The Range switch shifts the frequency window the filter works in, trading vowel-like character in the low setting for more overtone emphasis in the high setting1.
Analog circuit, true bypass, power
MusicRadar reported that the B-Tron III features an all-analog optical circuit2, the same basic approach as the original Mu-Tron III, which Musitronics lists as an analog envelope filter3. The pedal uses a true bypass design, so your signal passes through untouched when it is off2. It runs on standard 9 V DC power, and Behringer describes its metal construction as rugged and reliable enough for the road1.
History and the Mu-Tron III connection
The B-Tron III traces directly to the Mu-Tron III, an envelope filter made by Musitronics in the 1970s. Guitar World's history of the pedal describes it simply as "an envelope filter called the Mu-Tron III"4, and Musitronics still builds versions today, including the Mu-Tron III Vintage Silver, an analog envelope filter with envelope control of the filter3.
Behringer launched the B-Tron III in February 2025, making it available for pre-order at $69 in the US and £69 in the UK2. Gearnews later listed it at $51.00, so the price has moved since launch5.
Published prices disagree. MusicRadar and Guitar World both reported $69 at the February 2025 launch26, while a Gearnews listing from February 2025 shows $51.005. Both figures are given here as stated.
The Musitronics dispute
The launch drew a sharp response from the original maker. In February 2025, Musitronics posted on Facebook accusing Behringer of copying its products, trade dress and history with the $69 B-Tron III2. Guitar World called the pedal "a not-so-subtle $69 replica of its Mu-Tron III envelope filter"6.
"a not-so-subtle $69 replica of its Mu-Tron III envelope filter"
The B-Tron III is one of several Behringer filter releases aimed at classic designs. Like the rest of the company's recent pedals, it is built in a rugged and reliable metal construction intended to stand up to the rigors of the road, and it runs on standard 9 V DC power, which makes integrating it into an existing pedalboard straightforward1.
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Questions
Is the Behringer B-Tron III true bypass?
Yes. MusicRadar reported that the B-Tron III uses a true bypass design, so with the pedal switched off your signal passes through without active circuitry in the path. Behringer houses it in a metal enclosure built to stand up to touring.
What power does the B-Tron III use?
It runs on standard 9 V DC power, which Behringer says makes it easy to integrate into an existing pedalboard setup. No battery operation or current draw figure has been published, so plan on a normal 9 V center-supply from your power unit.
Is the B-Tron III analog or digital?
It is analog. MusicRadar described the B-Tron III as featuring an all-analogue optical circuit, following the same approach as the original Musitronics Mu-Tron III, which Musitronics itself lists as an analog envelope filter.
What is the difference between the Up and Down drive settings?
The Drive switch selects the sweep direction. Behringer says the Up and Down modes give either a traditional wah sound or a cocked wow sound. In practical terms, one setting sweeps the filter upward as you play harder and the other sweeps it downward.
How much does the Behringer B-Tron III cost?
At launch in February 2025 it was priced at $69 in the US and £69 in the UK, according to MusicRadar and Guitar World. Gearnews later listed it at $51.00, so street prices have varied since the launch price was announced.
Why did Musitronics criticize the B-Tron III?
In February 2025 Musitronics, maker of the original Mu-Tron III, posted on Facebook accusing Behringer of copying its products, trade dress and history with the $69 B-Tron III. Guitar World called the pedal a not-so-subtle replica of the Mu-Tron III.
Sources (6)
- B-TRON III ENVELOPE FILTER, Behringer
- “This thing is your one-way ticket to funky town”: Behringer's long-awaited Mu-Tron III clone arrives and promises a rabbit-hole of retro-funk tones for just $69, MusicRadar, 2025-02-06
- Mu-Tron III Vintage Silver, Musitronics Mu-Tron (mu-tron.com)
- How the Mu-Tron III became a vintage pedalboard icon, Guitar World, 2026-02-09
- Guitar Journal: QOTSA, Mu-Tron vs Behringer, & Black Sabbath, gearnews.com, 2025-02-11
- Behringer blasted by Mu-Tron III maker over $69 replica, Guitar World, 2025-02-17
