Trance Audio Inc. FAQ

Q) Will the Acoustic Lens pickup work on any guitar?

The Acoustic Lens pickup was designed and voiced specifically for the steel string guitar. It can be installed on most steel string guitars but because of its mounting location requirements, it will not work in some instruments. For more info, please check out our detailed article on the subject here.

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Q) Will the Acoustic Lens feed back?

The Acoustic Lens is designed to accurately reproduce the tone and nuance of your guitar at very respectable volume levels without excessive feedback problems. Ordinary contact pickups rely on the vibration of the instrumentšs top and body to sense and create sound. In essence, the entire instrument becomes a large microphone, and often tends to feedback at lower volume levels. Saddle transducers sense pressure vibration directly from the strings and either attenuate or ignore completely any vibration from the body. This provides a much greater immunity from feedback, but a much less realistic sound, leading many to declare the saddle transducer's sound as brittle, thin or twangy, and bearing little resemblance to the actual sound of the instrument. Any alternate techniques such as slapping or tapping the instrument are greatly attenuated, or ignored altogether.

The Acoustic lens is designed and custom voiced to mount with a special adhesive on the bridgeplate inside the guitar, underneath the saddle area. This spot allows it to essentially share the best of both worlds, and provides a very effective, integrated approach to sound reproduction. It gets direct vibration from the strings and saddle, allowing it to generate louder stage volumes than a standard contact pickup, and it senses the essential body vibrations and resonance that elude the saddle transducer and give a guitar its characteristic voice. Alternative techniques are faithfully reproduced, much the same as if the instrument were externally miked, but without the attendant problems.

It is possible to create conditions where the Acoustic Lens will feedback; a loud monitor pointed directly at the instrument (yes, we've had users do this), a sound system with "hot spots" where certain frequencies are boosted out of proportion to the rest of the spectrum, and other situations of this sort. A decent, full-range flat response system with properly positioned monitors will allow you to obtain very respectable stage volumes. How loud? Well, not as loud as a saddle transducer, but louder than a system with an internal or external microphone, and better, more natural reproduction than both. To give you a basic idea, Aerosmith has toured using an Amulet system with two Gibson SJ200's. If they can use the Acoustic Lens onstage, then you probably can, too.

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Q) Can I use the Acoustic Lens with other manufacturers' preamps?

In a word, no.

The Acoustic Lens poses a unique set of problems to amplify. It produces a very low output level and requires a very high input impedance to accurately reproduce a signal. Other commercially available preamplifiers, even the so-called "Piezo" types are designed to work with the output of a saddle-type or contact transducer, which put out a signal level typically 10 times higher than the Lens. Trying to use this type of preamp will result in a low level, hissy, thin sound which will certainly not do justice to the audio quality that the Acoustic Lens is capable of when properly amplified. The preamps that we build are audiophile quality systems designed specifically to meet the needs of the Acoustic Lens and interface it perfectly to the rest of your amplification gear.

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Q) Can I combine the Acoustic Lens with another type of pickup?

Not with the Amulet M, M-V or M-VT mono systems. The Amulet stereo system, on the other hand, has two completely independent channels, and is able to mix or match the Acoustic Lens with other transducers, or to run two Lenses as a stereo pair. It can easily support a magnetic or saddle-type pickup in combination with the Lens, and the gain trimmers inside the internal preamp allow you to easily match the levels of your favorite pickup to the Lens. Some of our customers are looking to duplicate a two pickup system such as the one favored by Michael Hedges, and the Amulet is designed to easily provide this sort of tonal flexibility with a minimum of equipment and interconnect problems. The internal preamp uses gold plated RCA connectors on the inputs, so to connect your favorite magnetic or saddle-type transducer, just solder an RCA plug to its connector cable and plug it directly into one channel of the preamp. The Amulet provides all the gain needed without any other external preamps or connections and provides sound and performance that our customers say exceeds other commercially available systems.

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Q) How well will the Acoustic Lens work with lowered and alternate guitar tunings? What is the difference between using two Acoustic Lenses or one Lens and a magnetic pickup?

The stereo Amulet system has one Lens mounted on the treble side of the bridgeplate, and one mounted on the bass side of the bridgeplate. Between them, they provide a complete, balanced reproduction of your instrument. You can pan the pickups to create a stereo image as well, anything from a subtle widening to a sweeping panorama as you strum the strings. Panning the pickups to the 10 and 2 o'clock position provides the most natural stereo perspective. Because of the way the Lens senses both string and body vibration, the bass side Lens will have no problems with lowered tunings on the instrument, often a problem with standard contact pickups.

When a guitar is tuned down, the top begins to vibrate less, and the output from a standard contact pickup drops off accordingly. In the past, players would often add a magnetic pickup to amplify the low end of the guitar when using standard contact pickups in an attempt to overcome the low-end deficiencies of these devices. Magnetic pickups sense the strings directly, and produce plenty of bass when using lowered tunings, but provide a less "acoustic" response, since they pick up very little information from the top and body of the instrument. These pickups also work much better when you use steel or nickel wound electric guitar strings instead of acoustic strings. The windings on acoustic strings aren't made of magnetic material, so the magnetic pickup only senses the smaller core wire of the string, providing less output. This poses an interesting dilemma; electric guitar strings work better for the magnetic pickup, but sound worse acoustically with the contact pickups. It's a double-edged sword, and each side has distinct pluses and minuses. Some string manufacturers have recognized this problem, and make strings that attempt to address these problems (GHS White Bronze, DR Zebra, etc.) and may prove valuable in these situations.

Some players have come to enjoy the sound of the magnetic pickup, and it does blend well with the Acoustic Lens; each brings something different to the party, and the overall sound can be quite pleasing. When mixing pickup types, the stereo aspect is lost, or at least reduced in naturalness; since each pickup now sounds somewhat different, panning them very far apart sounds more effected than natural, although it can give the suggestion of two instruments playing together in some cases.

The stereo Lens setup does the best job of reproducing the "acoustic signature" of the guitar. Players who like to thump their palms on the bridge may find a bit more output than they expected, however. Since the bass side Lens is mounted in that area, it's kind of like tapping on a microphone; tapping lightly sounds good, tapping too hard will start to air- condition the audience from the flapping woofers in your speaker cabinets! The Amulet Stereo External Controller has a switchable low-cut filter (and the Amulet M has this filter built-in) that is designed to alleviate this problem without compromising the quality and range of sound. Using EQ to limit the lowest range of your system is another option, and many mixers provide a low-cut filter for just this purpose.

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Q) If I use an Acoustic Lenses and a magnetic pickup on my instrument, do I need a separate endpin jack for each?

If you have the Amulet M, M-V, or M-VT mono systems, yes. But if you have the Amulet stereo system, there are some options as to how to work this. You can use one Acoustic Lens transducer to pick up only the treble strings of the guitar, and run the magnetic pickup through the other channel of the Amulet preamp. In this case, both the Lens and magnetic pickup signals will run through one endpin jack, though you do lose any Lens coverage of the 3 lower strings of your guitar.

You can also parallel two Acoustic Lens transducers together using a specially shielded Y-cable that we have available, and plug them into one channel of the internal preamp, while the second channel accommodates the magnetic pickup. This widens the covered range of the Lens channel, and changes the overall tone of the transducers somewhat. There is less treble response, and increased midrange, which may appeal to some players. In this setup, the stereo aspect of the Lenses is lost, as they are now paralleled together.

If you wish to keep the stereo aspect of the Lenses and use a magnetic pickup, a second endpin jack can be added to the instrument to bring out the signal from the magnetic pickup separately. This adds more cabling to the instrument, but increases the tonal flexibility.

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Q) If I want to install the Amulet stereo system on more than one instrument, do I need a complete Amulet system for each one?

For users who wish to use more than one instrument with our stereo Amulet, we make the 2nd Guitar Kit available. This kit contains an additional internal stereo preamp and endpin jack and one or two Acoustic Lens pickups. This allows you to share the Amulet external controller and its amplifier connections with two or more instruments, without the added expense of completely duplicating additional systems. As a bonus to our customers, these kits are supplied at a substantial discount over the price of the individual components.

The gain trimmers located inside the internal preamps allow you to match volume levels between multiple instruments as well, to make for a smooth transition from instrument to instrument.

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Q) What type of amplifier/speaker works best with the Acoustic Lens?

The Acoustic Lens has been voiced to work best with a flat response, full range system. The better the frequency response of the system, the better the Lens will sound. There are a number of "acoustic" amplifier combos on the market, some better than others. Better still is a system like a small PA system, with component mixer, amp and speakers. These types of systems will generally have a better frequency response, more dynamic range and more flexibility. Avoid electric guitar amplifiers, which have a limited frequency response. These sound fine for electric guitars, but don't do justice to acoustics.

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