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The secrets of getting transparent tone from transducers

The last thing you want is a pickup system that colors your instrument's natural voice or it's subtle overtones and harmonics. This article will discuss the differences in transducer types and construction. It gives some insight to getting the quality of a studio condenser microphone from simple soundboard transducers. We will not cover magnetic, mini condensers, or multi-source in this writing. We will instead save that broad category for another day.

Soundboard Transducers

If you have to pick one type of pickup, we emphatically recommend Soundboard Transducers. They are often called SBTs in the industry. SBTs typically mount underneath the bridge plate, inside the instrument. They can be made using many designs and materials, but the most common types are ceramic piezo discs. You may understandably cringe when hearing the word piezo. Most piezos used by instrument manufacturers are the dreadful under-saddle (UST) type which are commonly made from the same cheap cable that triggers stop lights when buried in the asphalt. It is no surprise that the tone sounds buried too. Unlike USTs, SBTs are not under pressure or compressed. They have lower output, but hve a much more balanced frequency response and natural sound.

Before associating SBT pickups with the quack of USTs, give these two videos a listen. We want to show the profound difference in SBT and UST type piezos. Both $500 guitars were recorded through Archangel x7 preamps. Both have minimal equalization and have added only a touch of reverb.

The first video is a Takamine Palathetic UST type pickup. It has recieved great reviews and much praise over the years (for some reason that completely escapes us).

Fast forward this first video to 6:00



The second video is a set of Elevation SBTs.



As you can hear, the SBTs are natural and a faithful reproduction of the instrument in the room, and the USTs have the familiar compressed plastic midrange quack that no premp in the world will completely eliminate. We highly recommend using SBT pickups, and likewise recommend avoiding UST types with our preamps if possible.

The drawbacks to piezo pickups

The sensitivity and frequency range of piezos can be missed altogether if their very high impedance (which is a common trait for the PZT materials they are constructed from) is not conditioned to a low impedance with a buffer. When piezo pickups are plugged directly into a low impedance input unbuffered, the result is a thin and hash sound that gets progressively worse with longer cables. This is where our preamps shine. When you process SBT pickups through our proprietary buffer and filter design, the result is a completely lifelike and natural tone, that rivals that of the finest studio condenser mics. Our preamps allow you to easily carry that pristine studio clarity up on stage with you in live venues. Our filter designs are tuned to the fundamentals, overtones, and harmonics of many types of acoustic instruments. This Archangel exclusive tuning gives a wide and flat frequency response and allows us to control feedback like has never been possible with other products.


Another issue that can arise is handling noise. Mounting plays an important role in the percussive attack from hitting the bridge with your palm. Too much attack and you get a DC voltage spike that clips everything in the audio system it is plugged into. If it is right you get the gorgeous knocks and taps that modern fingerstyle players love. We recommend using CA glue (super or krazy variety) to mount transducers to the bridge plate. Most players like mounting the as far forward on the bridge plate as possible toward the soundhole. We have also had great results mounting them on the back side of the bridge plate for a really natural microphone type of response. If you mount them toward the rear of the plate though, you can get a bowing effect heard as a squeak caused from your palm print bowing against the bridge pins. If you have an instrument without bridge pins this is our favorite mounting position.

Mandolins and violins are a little tougher than guitars. It is tempting to stick transducers directly to the soundboard, however that causes crazy resonance and can cause distortion or clipping from the energy transferred from the soundboard's intense resonance nodes and movement. The better solution is to mount transducers to the bridge itself or inside the instrument underneath the two ends of the bridge, avoiding the soundpost, if equipped as is found in violins and others in the string family of instruments.

Transducer construction plays a huge role in SBT performance. Control of the natural resonance of the piezo element is done by potting it, sometime called a "pellet". If done properly, potting will give the transducers in the set damping to control resonance and even output level from each element. Some builders have a big problem with inconsistent output between transducer elements, especially those who use a hard cast resin potting. We have found two brands of transducer systems that control resonance,and balance levels extremely well. It is a result of their semi-flexible polymers used for potting, and their consistent precise construction techniques. These qualities and outstanding customer service are the major considerations in our recommendation of two specific brands of transducers to our customers.

We use and recommend:


JJB Electronics Prestige 330 System

We have designed many preamps with JJB transducers, including our first production model. We have done business with the folks at JJB for many years. They have models for many types of instruments including guitars, banjos, ukuleles, mandolins, and violins. Their transducers are also used with percussive and exotic instruments like tongue drums and cajons. We have always been able to confidently refer our customers to JJB for their great products and exceptional customer service. Customers love the pricing that delivers great tone, even on a slim budget. We also build OEM electronics for JJB and are proud to be a small part of what they are doing. Give them a visit at www.jjb-electronics.com and see all that they have to offer.

BGM Electronics Elevation EV-1.3 and E-3 Systems

We partnered with BGM Electronics in North Carolina to develop radically different transducer and mic systems that work very well with our preamps. Elevation Systems are like nothing else in the industry. They use very high quality nickel sensor elements with a reactive cross-linked thermal polymer potting that is weighed to the 10th of a gram for amazing balance and resonance damping. They also use tiny 1mm premium Mogami shielded cable. This makes for an ultralight set of transducers coming in at only 1.2 grams each including the cable. We have known the folks at BGM Electronics for thirty years, so we know their products and customer service are top-shelf. Elevation transducers are currently in the studio and on tour with some amazing CandyRat contemporary fingerstyle giants and Nashville pros. Give them a visit and see what's new at www.bgmelectronics.com





What about using other pickups with Archangel Preamps?

We have happy customers all over the world that use a multitude of different systems. We have had great reviews and testimonials from customers that use brands like Baggs, McIntyre, K&K, Dazzo, Schertler, Fishman, Dimarzio, Sunrise, and many more including magnetic and even EMG 18V active electronics and active bass guitars.

 

 

Everyone's application is different. Everyone's ears and instruments are different. The one thing that stays the same is that we all want the best tone possible. Archangel puts tone over profits and without hype. You will hear the difference immediately.