Introduction 

Many violinists with an “amplifier-ready” (i.e. has a pickup) instrument try to use effect processors to extend their sound palate. Effect processors are usually called “guitar effect boxes”, because such devices have historically been marketed to electric guitarists. Such devices are often referred to by their nickname, “stomp box” (referring to the way they are activated, by stomping on a switch with one’s foot). Many amplifiers come with a selection of common effects built into the amplifier housing.

Widespread Mistaken Beliefs

Study of a large number of discussion threads on online violin and fiddle special interest websites reveals that there is a lot of misinformation about violins and effect signal processors on the web. Widespread wrong information on the web?...say it ain’t so! (sarcasm). Here are a few:

• Most effect processors do not work with violins.
• A bowed note is different from a plucked not and, therefore, somehow does not “track” with many effect processors.
• All guitars, regardless of their pickups, do work with most effect processors.

Hopefully, this article can dispel these mistaken beliefs and set you on your way towards using just about any effect signal processor with your violin. Warning: You may have to get another violin. This may be the first time that many of you would have to spend serious money in furtherance of your art. We know that it is virtually a part of the fiddlers’ unofficial creed that one should not have to spend money on just about anything. This includes decent strings, tuning pegs that work, good bows or even a quality instrument.

The Classic Effects

These are effects that have been around in one form or another since the 1960s. They include things like tremolo, reverb, delay, compressors, limiters, overdrive, distortion, echo and basic chorus. The main difference between effects of this sort made 50 years ago and those made today is that the newer ones are more electronically sophisticated and work better. In fact, the earliest echo and reverb units were completely electro-mechanical in nature.

What the classic effects have in common is that they do not do any heavy duty signal processing requiring the processor to accurately detect the frequencies in the input signal. These old school processors will take just about any signal thrown at it, including human voices via microphones, and do whatever it is they are designed to do.

The Classic Effects and Violins

These effects, needless to say, work flawlessly with guitars with just about any kind of pickup(s). Further, I know of no situation where a violin, whether it be an acoustic violin with a pickup or an electric violin (even the cheap ones), has failed to work with any of the “classic” effect processors.

Unfortunately, these effects that DO work with most violins are NOT of much interest to most violinists.

The Problematic Effects

The Problematic Effects are those that many violinists desire. We call them the “Cool Effects”. They are also the ones that DO NOT work with most violins. Included in this group of effect processors are:

• Octave converters (generate notes 1 or even 2 octaves lower than the unprocessed signal)
• Pitch shifters
• Harmonizers
• Detuners (aka “anti-chorus”; by mixing a processor generated note that is slightly pitch-shifted with the original note, simulates two violins playing in unison)
• Exotic effects, such as an effect that generates the sound of sympathetic strings (can make a violin sound like a viola d’amore or a Hardanger fiddle)

What do these “problematic” effects have in common?

All of the effects mentioned above, and ones similar to them (e.g. overtone generators; sub-harmonic generators, etc.) involve heavy-duty signal processing. It is essential that these signal processors determine, in near real time, the fundamental of each and every tone in a signal. Put another way (and anthropomorphizing a bit), the signal processor needs to “know” exactly which notes it is dealing with…and really fast (a millisecond at most).

Why these effects are a problem for violins

Violins and guitars have this in common: the tones (notes) they generate are NOT a single frequency. Rather, they generate notes that are comprised of a fundamental (the note that is heard by a human and measured by a digital tuner), together with a large number of overtones, which we call the “harmonics”. A fundamental and its set of associated overtones is called a “frequency spectrum.”

A simplified ideal frequency spectrum for a violin note, as heard by a human, is shown below.

Electric guitars that are set to “flat” (EQ set to neutral for all bands) and the tips of violin bridges (where the strings contact the bridge) produce well-organized frequency spectra where the fundamental has the highest amplitude (volume), which is usually measured in decibels (dBs).

The following idealized frequency spectrum graph illustrates this:

A frequency spectrum graph of the sound emanating from a violin top is not even close to a graph based on measurement from the bridge tip. See the illustration below, which shows (using the color red) the points at which the overtones actually have higher amplitude than the fundamental.

The following illustration attempts to convey the magnitude of the difference from what is recorded from a violin top and what is measured from its bridge tip.

It is noteworthy that all of the above frequency spectrum graphs are based on actual spectrum graphs of a Stradivarius violin. So we can safely assume that instrument quality is not an issue here.

There is no way that a signal processor whose operation depends on “knowing” the note it is dealing with to do anything useful with such a frequency spectrum. Interestingly, a human brain’s auditory processing system has no trouble reorganizing the apparent chaos captured in the above illustration into a sound that makes sense. In other words, what a human hears is closer to energy recorded from the violin bridge tip.

The next illustration shows the difference from a violin top frequency spectrum and what is ideal for a signal processor. The heavy blue line indicates the ideal.

So, Where Are We?

We know that measurement of where violin strings contact the bridge yields a very different frequency spectrum graph than a graph based on the sound emanating from the instrument body, particularly its top. It is only the former (i.e. strings touching the bridge) that produces energy, which can be interpreted by certain signal processing devices (i.e. the problematic ones).

All of what has been said appears to explain why effect signal processors work fine with electric guitars, but only with a minority of violins. With electric guitars, generating a signal is all about changes in electro-magnetic energy in response to string vibration. It is the vibrating strings interacting with powerful electro-magnetic pickups that produces the signal.

This brings us to pickups.

A Brief Survey of Attempts to Make Violin Pickups

Buidling a Better Violin Pickup

Over at least the past 50 years, there have been countless attempts to invent violin pickups that actually work. Generally, there has been no major difference between pickups used on full-on electric violins and so-called acoustic-electric violins.

Curiously, while there have been attempts, magnetic violin pickups similar to those used on electric guitars have never caught on in any significant way.

Most magnetic pickups for violins, since the beginning and today, don’t sound very good (by any definition of the word), at least not without the help of industrial strength equalizer preamps and other signal processing equipment. Even then, some still sound thin and tinny.

In any case, every attempt that I know of to bring a magnetic violin pickup to market has ended up being rejected. An even larger impediment to adoption than unprocessed sound quality is the fact that magnetic pickups require strings with a ferrous (e.g. steel) core. Only a small minority of violin strings has a steel core. Violin strings have cores either of some type of polymer fiber or a non-ferrous (i.e. NOT MAGNETIC) alloy.

Overwhelmingly, pickup designs have, over the years, involved piezoelectric elements that are...

• Stuck to the bridge
• Wedged in the bridge wings
• Stuck to the violin body
• Situated between the violin’s bridge and top plate
• Cheap violin under bridge pickup (worthless)
• High-quality pickup bridge pickup (sounds pretty good)
• Embedded into the bridge
• Single transducer epoxied into a hole drilled or routed into a regular bridge (probably the most popular type used on acoustic violins)
• Multi-transducer a la Barbera Transducer Systems
• Other strange methods
• What looks like a tire inner tube wrapped around the instrument mid-section
• Small mic on a gooseneck attached to the tailpiece ... mic aimed at violin top

Images for some of the pickups listed above (click on any of the thumbnails for larger views.)

The only pickups that we know will work with any effect signal processor we have encountered 100% of the time are those by Barbera Transducer Systems or a pickup that is based on the same theory of operation. In fact, we have installed these pickups on a number of instruments, including experimental violins designed specifically for driving effect signal processors. The pickups have worked flawlessly with octave, harmonizer, detuner, overtone generator and sub-harmonic generator effects (all deemed to be impossible for violins!). We have been able to simulate a contra-bass with a Barbera augmented violin by taking it 2 octaves down and driving a 400 watt bass amp outputting to massive subwoofer system. This worked without a glitch in an instrument design competition live performance.

Most of the pickups above will NOT work predictably well with the most sophisticated effect signal processors. Those that contact the tops of instruments in any way are a complete lost cause. It is only the pickups with transducers embedded in a bridge that have a fighting chance of working.

We have specified Barbera pickups for our soon to be released electric violins specifically designed to drive signal processors, the FX-1 Venetian Series 4-string and 5-string electric violins. See product listings at the Don Rickert Musician Shop:

• D. Rickert FX-1 Venetian Series Arch Top Electric Violin (Pegbox version) Special Pre-Release Hand-Made Edition
• D. Rickert FX-1 Venetian Series Arch Top Electric Violin (Slot Head) Special Pre-Release Hand-Made Edition

See also these blog articles:

• Announcing D. Rickert FX-1 Venetian Series Arch Top Electric Violins
• D. Rickert FX-1 Venetian Series Arch Top Electric Violins

Why the Barbera Pickups DO Work Well with Signal Processors

Barbera pickups are based on a theory of operation that is the opposite of the approach taken by some other pickup manufacturers. According to Barbera, placing a single large transducer between the bridge and the top plate results in what is called a surface sensitization effect; whereby the resonant surfaces of the instrument become microphonically active (e.g. the top of the violin becomes a microphone, in effect). This results in an unfocused signal, as there is very little selectivity in the way that the vibrational information is collected. This means that everything gets amplified.

Barbera, instead of putting a single transducer under the bridge, embeds 4 piezo elements PER STRING near the part where the string contacts the bridge. For a 5-string, that is 20 transducer elements. As one would imagine, the signal from a Barbera pickup is quite focused, and it is. The output signal contains unambiguous fundamental frequencies (higher amplitudes than the overtones). This is exactly what many effects that simply do not work with most amplified violins require, especially octave changing and harmonizer effects. These "impossible" effects work flawlessly with a violin using a Barbera pickup.

• Paradoxically, while producing very strong and clear fundamental frequencies for effects boxes, the Barbera pickups do, in fact, interact substantially with the vibrating top of the instrument to produce rich harmonics. It sounds great to the ear when amplified. The amplified sound is quite “natural”; just not exactly the same as the un-amplified sound of a specific acoustic violin.
  • To the ear the sound is full-range and focused. Also, the lower frequency harmonics are accentuated somewhat; but that is what most players, especially fiddlers, are looking for anyway.
• With the right combination of effects boxes, equalizers, amplifiers and signal routing switches, a violinist or fiddler can realistically reproduce a very natural amplified sound of a cello, double bass or even contra-bass (the lowest instrument in the bowed string family). The musician can also do things like add sympathetic string chordal accompaniment in any of the octaves.

Conclusion

Return to the Widespread Misinformed Beliefs Listed at the Beginning of This Article

Most effect processors do not work with violins.

Most effect processors DO work with properly equipped violins. Of the widely recognized top tier electric violins (Wood Violins, Jordan, Jensen, Vector, EVL Violins, Stratton, NS Design, Bridge, Yamaha and Fuse), the majority of these work perfectly with most effect signal processors. The best electric violins all use pickups that capture energy mostly from their bridge tips. It is not coincidental, that about 90% of the top electric violins utilize Barbera pickups.

See the photo album on our Facebook page entitled Some of the Best Electric Violins.

Further, the several dozen acoustic violins and violins for which we have installed Barbera pickups, all have worked perfectly with any effect signal processor tried.

A bowed note is different from a plucked not and, therefore, somehow does not “track” with many effect processors.

Whether a note is bowed, or generated with a pick, has NOTHING to do with ability to function with effect signal processors. It is all about generating a signal comprised of frequency spectra with a dominant fundamentals (i.e. higher amplitude than the overtones).

All guitars, regardless of their pickups, do work with most effect processors.

We did not really cover this one. The fact is that all guitars do not work well with signal processors. There are older guitars with lousy pickups that fail to generate a signal compatible with effect processors. Further, most new “value priced” acoustic-electric guitars use under-saddle piezo transducers. These do not work any better with effect processors than under-bridge piezo transducers on most electric violins.

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