science

Mu-Tron III

Mu-Tron III is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Mu-Tron III rather than just read about it. In short: The Mu-Tron III is an envelope filter made by Musitronics Corporation. "The world's first envelope-controlled filter" was first made in 1972 by Mike Beigel and quickly became an essential effect for many funk musicians. It was produced again, in a modified version, in 2014.

Key takeaways

Mu-Tron III belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Mu-Tron III to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Mu-Tron III from memory before moving on to harder problems.

Reference excerpt

The Mu-Tron III is an envelope filter made by Musitronics Corporation. "The world's first envelope-controlled filter" was first made in 1972 by Mike Beigel and quickly became an essential effect for many funk musicians. It was produced again, in a modified version, in 2014.

Mu-tron III Extracting elements from one of the prototypes of a synthesizer he was developing for Guild Guitar Company, Mike Beigel based the Mu-Tron III, at the instigation of Guild engineer Aaron Newman, on a prototype called the Timbre Generator. The Mu-tron III could be used for any number of electric instruments. Beigel said he chose the envelope-controlled filter over other synthesizer elements, such as ring modulation, because it sounded more musical; it was a more general effect that would lend itself to a variety of applications, and it was easy to use. The Mu-tron III was an instant success and was used by jazz/fusion guitarist Larry Coryell, Funkadelic bass player Bootsy Collins (for his "Space Bass"), guitarist Jerry Garcia, Yes bassist Chris Squire, and Stevie Wonder, who used it on his Clavinet for the song "Higher Ground". Beigel was successfully granted a patent for the circuitry of the Mu-tron III. Musitronics licensed the Mu-tron III circuitry to a few different companies in the seventies – the Univox Funky Filter and Monacor Effectmatic are notable examples. The original Mu-tron III ran on two 9V batteries used as a Bi Polar power supply; this gave it a wider dynamic range and more headroom compared to effects that ran on 9 volt. There was an optional power supply (the PS-1), and with later versions had built-in AC power supplies. The Mu-tron III used proprietary opto-isolators to control the filter, which was novel for the time, a method would also be used for the Mu-tron Phasor II and Bi-Phase. The state variable filter in the Mu-tron III allowed for low-pass, bandpass, and high-pass filter response, which could be triggered from low to high or vice versa. When ARP Instruments bought Musitronics in '79, they made the Mu-tron line for about a year before going out of business, and the Mu-tron III was no more. With the advent of the stompbox revival of the nineties, the Mu-tron III became one of the big-ticket items for collectors and players alike. There was a reissue of sorts, the HAZ Mu-tron III+, but Beigel says this (and other clones) did not have "the same magic". In early 1995, however, Beigel did lend his expertise to Electro-Harmonix, creating an update of his original design, the Electro-Harmonix Q-Tron, and he also designed a Bi-Filter for E-H. Three other pedals, the Mini Q-Tron, Micro Q-Tron and Q-Tron+, are available from EHX as well, who now also offer the Bi-Filter, a modern version of Beigel Sound Lab's Envelope Controlled Filter, made in 1979. Michael Dregni, in Vintage Guitar, noted that none of the "clones, copycats, and other attempts to bring it back...sounded quite like the real deal". But in 2014, a renewed version of the Mu-Tron III, now called the Tru-Tron 3X, was made by Beigel's new company Mu-FX.

Tru-Tron 3X The Tru-Tron can work "exactly like the original", but has added functionality and range, and is "smaller and more robust" than the original. It runs on 12 volts. In addition to the original's ability to control the upsweep of notes it adds control over the downsweep, and offers more gain for more intense effects. It also has an internal potentiometer which allows the user to adjust the envelope filter's response time to match the player's style.

References

External links Official website Mu-tron.org – maintained by Mike Beigel, founder of Musitronics Beigel Technology Corporation Electro-Harmonix envelope filters

Illustrations

Mu-Tron III: A Mu-tron III envelope filter — A Mu-tron III envelope filter

Worked examples

Example 1 — a first encounter with Mu-Tron III

Start with the simplest possible case. Write down what Mu-Tron III claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Mu-Tron III before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Mu-Tron III ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Mu-Tron III

In research: Mu-Tron III appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Mu-Tron III in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Mu-Tron III is common in secondary-school and first-year university syllabi. It links to neighbouring topics Effects units, Signal processing filter, so understanding it makes those chapters shorter.
In everyday life: Look for Mu-Tron III outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Mu-Tron III in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Mu-Tron III means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Mu-Tron III out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Mu-Tron III in simple terms?

Why does Mu-Tron III matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Mu-Tron III?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Mu-Tron III.