Banjo Transducers 101, picking the right one for you
Amplification of the banjo is a topic that often comes up, so here is a bit of information to assist you in selecting a transducer for your banjo should you find it necessary to perform live and amplified. Please note that I’ve loosely defined transducer into the three main categories; piezo-based transducers, magnetic transducers (commonly referred to as magnetic pickups), and microphones of various types. A few other sub-genres are also thrown in for good measure. Please feel free to contribute your thoughts, as I’ll eventually post this at my website, also. Some of the pickups such as the Jones or the Schertler transducer I’ve had little exposure to, so I’m welcoming additional comments from actual users.
1. The piezo transducer always has a characteristic sound that is a result of the way it converts mechanical energy to an electrical signal capable of being amplified. There are various descriptive adjectives used for this sound, it is often called “brittle” or “edgy”. If it is directed through a pre-amp some of the edge of the brittleness can be negated. This is the result of impedance matching the piezo material to the next stage of amplification. The hows and whys of this are beyond the scope of this information, but just suffice to say it generally accepted that it improves the resultant sound. Tone shaping may also be applied by the pre amp to further refine the sound if it is designed with those features. Because the primary source of the electrical signal is the vibrating head of the banjo, it is as a general rule much more difficult to control feedback with the piezo transducer.
2. A magnetic transducer or "pickup" senses disturbances of the magnetic field pattern generated from permanent magnets when a string moves within the magnetic field of the pickup. Since the resultant electrical signal is predominantly a result of only the string's vibration, it is most often cited as having a very "guitar-like" sound, no surprise here as it would closely mimic the same physical layout as an electric guitar.
Since the string is the predominant component of the generated electrical signal it tends to be the most feedback resistant, although unfortunately the least banjo-like in tone.
A subset of the magnetic transducer design is the hybrid technique of using a magnetic coil under a metal shim such as the Jones type of pickup. These certainly improve upon the sound of the straight magnetic pickup greatly as they are sensing both the string and head vibration as coupled through the bridge, although they also would have more of a tendency of generating feedback at high volume due to coupling of the head vibration.
3. A "single point sound source" microphone (clip-on small dynamic or condenser, external dynamic such as Shure SM-57, or small or medium diaphragm condenser such as AKG Perception 170 or AKG C 1000 respectively) will ALWAYS result in a much more accurate reproduction of a banjo's true tone. While the resultant sound will generally be quite good there will be a trade-off in a reduction of available stage volume through monitors before feedback becomes a problem. Many performers opt for the tried-and-true SM-57 for general PA use because it is relatively easy to get a good sound at moderate volume levels when using monitors.
A sub-set of the microphone amplification conundrum is the use of a large diaphragm condenser microphone (Rode NT1 as example) with performers controlling their individual volumes through the "microphone dance". As a live stage microphone large diaphragm condensers pose their own unique set of problems. The same reason they excel as studio microphones make them difficult to work with as live performance microphones if monitoring is desired. They CAN sound great at low volume levels with no monitor use IF the performers work out acceptable levels well in advance and has a dedicated FOH (front of house) sound person handle any of the adjustment while in use. If you need to use monitors or don't have a FOH person it may be better to examine another amplification technique such as the individual microphone option.
There are a few other types of transducers that use alternative technology to convert mechanical energy from the banjo to an electrical signal such as the Schertler transducer system and possibly a few others that I’m not familiar with. Additional comments would certainly be welcomed here.
The ultimate choice of what best works for YOU in YOUR situation will be a comparison of all the options including how high a volume you anticipate playing at, how important accurate representation of your banjo tone is to you, if you need stage monitors when performing, and if you desire to retain the ability to move around while performing. Let the balancing act commence!
Great synopsis -- this is a terrific primer on the ways to amplify a banjo.
I'm a Jones and Fishman user, but I keep getting the urge to solder up some piezo film and experiment -- something along the lines of Pickup the World or McIntyre designs. My only concern is that it would turn the pot into one big feedback generator. Anyone try this type of pickup and have experience with controlling tone and feedback?
Thanks Peter. If you want to try the piezo route, I've played pretty extensively with the disc option and have directions for putting one together here. I've made a few of these for fiddle players who think it sounds really quite good. I stuck one about 1/2" behind the center bridge foot on the underside of a banjo head with double-face carpet tape and it did a pretty good job on my Nylon-strung jo. It was certainly good enough to play a few gigs with, obviously you need a preamp between it and the PA, though.
Thanks, Randy -- I made a disc-type pickup probably 30 years ago. Sorta worked, but I didn't shield it and I could never get good contact with the head. I just might try it again and do it right, just to see what happens.
I play with a seven piece band switching from electric guitar to banjo fairly frequently. We have drums, guitars, mandolins, fiddle, sax and bass, so needless to say it is a lot of sound in a live environment. When we started I had a Deering Goodtime with a Shatten piezo pickup under the bridge running through effects then into my Fender Hotrod Amp. It sounded surprisingly good. Unfortunately with my latest Huber the resonating chamber has been feeding back almost every gig. I think the jump up in quality of banjo made for a better feedback generator. Now I am looking for a quick and nonubtrusive fix with perhaps a rare earth pick up. Does anyone know what the rare-earth through a fender amp would sound like?
I just tried running my OME with a Jones pickup into a Goodsell tube amp -- it's a guitar amp somewhere between a Tweed Deluxe and a Vox. it actually sounded pretty good for a live, outdoor gig, and it was easier than getting the soundman to deal with the DI output of the pickup coming back in the monitors. I tried this at practice using my Gibson with a Fishman pickup (pre-Rare Earth, so no built in pre-amp) and it worked, too. The sound isn't pure, pristine acoustic, but with the electric instruments and drums, it sounded fine.
I'm wondering the same thing about the Gold Tone ABS, I play with a drummer, and wonder if it would pickup that sound, we play side by side (it's a duo) so I'm pretty close to him sometimes.
PeterJ- I currently use a Pickup the World piezo. Great guys to deal with. I run it through a LR Baggs para acoustic DI. The nice thing for me is the soundguy, always the house guy, can patch it directly into the PA. I've used amps on stage though too when provided, which is fine as well, I prefer the PA though.
I much prefer the PUTW piezo over the Schatten I used to use, which was way way too bright for me (evidently it works for some, I had two, neither did it for me). So the PUTW was a nice surprise, but it still misses some of that acoustic-ness on stage and tends towards the bright side (you can turn up the bass on the Baggs DI, but that is the same frequence that my head gives off evidently, so not always an option) and I'd like some more over all punch. But then again, I'm using a Goodtime openback, the older kind with that goofy Gubmy headstock (I guess they figured you gotta pay somehow for getting away with a decent cheap amercan instrument).
One disadvantage of having a piezo on the underside under the bridge is if you frail and strike the head, well that gets amplified too of course. Otherwise there is a strong clear signal coming out...
But that plus the idea of adding an ABS or something similar has been in my mind: there's a post on this banjohangout.org/topic/214341. Corn has a good system it seems.
Member Paul Roberts, who's a killer experienced player by the way, especially when it comes to tone, and the Gold Tone dealer I would go to, mentioned that he was going to receive a new version of the ABS soon and would review it once he has.
Oh, I forgot, then there's the Kavanjo head system. A really nice guy too, but I'm wondering how all that mass would affect the acoustic sound of the banjo, especially the overtones, mainly on an openback, which I would think would be more sensitive to that situation.
Otherwise, if just for the stage situation, it sounds like it's very low on feedback and high on power. This is just my forum experience talking, but the guys in the videos on their website really bang it out.
Thanks for telling us about the PUTW pickup, Elwood. I've read good things about it, but never heard one in use. It seems similar to the McIntyre, so I imagine they get similar results. The Schatten's design is very different, with a much smaller contact point, so I'm not surprised it gives a different result.
I'd be curious about how the K&K system sounds too. I recently installed their Pure Archtop system (two internally mounted transducers) in an older archtop I have and it does sound pretty natural... pretty much just like the guitar.