I’ve tried 1/32” piezo material between the bridge and the body and I’ve tried it in the bridge. Our guitar player is also a violin maker and has made all of our violins. He explained to me the reason I couldn’t get the right sound, and the reason the violin player didn’t like the sound, acoustically, was because the pickup changes the violin. The pickups that use the bridge cause problems. It ruins the instrument from being played acoustically. Just the pick-up sitting under the bridge changes the sound of the violin too much. The bridge of the violin is a mechanical preamp/EQ for the instrument's body which amplifies the sound. By placing anything in or under the bridge changes the violin's sound too much for the musician. It ruins it from being played unamplified. We found that one pick-up under each foot of the bridge and one pick-up in either side of the bridge, gave us a harsh, brittle sound. It sounded like the violin was being played in a long pipe. By completely removing the side pick-up (only using the 2 under the feet) got rid of a lot of the harshness. 2 pick-ups worked better than the 3 but still not a good sound even with EQ'ing. By removing the 2 pick-ups under the feet of the bridge and placing them in the side slots of the bridge, we diminished some of the pipe sound, but the brittle, harsh, sound was really bad. The problem with the acoustic properties of the violin does NOT return by moving the pick-ups from under the bridge to into the sides of the bridge. It apparently is not a problem of isolation between the violin body and the bridge but more of a problem of change the vibrating characteristics of the bridge.
I have not used PVDF foil and maybe should try some before giving up on bridge pickups.
As for input, a current input should be good. This was used for measurement inputs like for vibration transducers. Protect it very well by clamping with fast diodes to supply rails.
Will you please explain this more? I do not understand what you are telling me. I am just a beginner at electronics.
Thank you,
steve
I have not used PVDF foil and maybe should try some before giving up on bridge pickups.
As for input, a current input should be good. This was used for measurement inputs like for vibration transducers. Protect it very well by clamping with fast diodes to supply rails.
Will you please explain this more? I do not understand what you are telling me. I am just a beginner at electronics.
Thank you,
steve
A current input is the input of an I-V convertor like it was/is used on DA convertors. It is nothing more than when you take an inverting opamp, and remove the input resistor, connecting the piezo direct to the inverting terminal of the opamp.
A piezo works by shifting charge. So it represents a current source. That's why it is so strongly influenced by cable and input impedance, it has a very large output impedance.
Protection is needed because if you tap a piezo hard (even the 12mm ones) they can easily output 10 to 30 volt. Now most opamps do not like this at their inputs, certainly not if you use the I-V stage, where the input is directly connected to the inverting terminal. So you put some very fast, low capacitance diodes from the input to the supply rails of the opamp. In normal operation, the diodes are reverse biased, put if the input voltage rises above/below the supply, they clamp the input to the supply rail, preventing damage. Something like a 1N914B, or BAV99 or BAT54 should do.
A piezo works by shifting charge. So it represents a current source. That's why it is so strongly influenced by cable and input impedance, it has a very large output impedance.
Protection is needed because if you tap a piezo hard (even the 12mm ones) they can easily output 10 to 30 volt. Now most opamps do not like this at their inputs, certainly not if you use the I-V stage, where the input is directly connected to the inverting terminal. So you put some very fast, low capacitance diodes from the input to the supply rails of the opamp. In normal operation, the diodes are reverse biased, put if the input voltage rises above/below the supply, they clamp the input to the supply rail, preventing damage. Something like a 1N914B, or BAV99 or BAT54 should do.
I once experimented with such a cheapo transducer on a Kora, where I placed it under the bridge. Since this instrument has a soft thingie between the bridge and the "body" the transducer's resonances are damped quite well.
I think a current input would damp resonances even better. I don't think that it is necessary to connect the protection diodes between the input and the supply lines. The inverting input of an opamp in this circuit represents a "virtual ground" so that the protection diodes can be connected antiparallel between the inverting input and signal ground. And don't even bother to question if this works at all, I already used it successfully in another situation !!!!!
Regarding the sound quality of commercial piezo pickups: Just have a listen to Victor Wootens "A show of hands". The tune "overjoyed" for instance is recorded using piezo pickups. The sound is very tranparent, the only disadvantage are the subsonics generated by the plucking, that make you fear for your woofers if you crank it up a little......
The transducer which Bob pointed at reminds me of a thingie called "C-Ducer" a colleague once used on an upright piano. It must have been resonant like hell on some frequencies because some keys sonded sharp as hell and other ones nice. It behaved very well on an acoustic guitar however.
Regards
Charles
I think a current input would damp resonances even better. I don't think that it is necessary to connect the protection diodes between the input and the supply lines. The inverting input of an opamp in this circuit represents a "virtual ground" so that the protection diodes can be connected antiparallel between the inverting input and signal ground. And don't even bother to question if this works at all, I already used it successfully in another situation !!!!!
Regarding the sound quality of commercial piezo pickups: Just have a listen to Victor Wootens "A show of hands". The tune "overjoyed" for instance is recorded using piezo pickups. The sound is very tranparent, the only disadvantage are the subsonics generated by the plucking, that make you fear for your woofers if you crank it up a little......
The transducer which Bob pointed at reminds me of a thingie called "C-Ducer" a colleague once used on an upright piano. It must have been resonant like hell on some frequencies because some keys sonded sharp as hell and other ones nice. It behaved very well on an acoustic guitar however.
Regards
Charles
Which it will always be under normal conditions, i.e. if the opamp insn't driven into clipping or if it's max slew-rate isn't reached.
If these two conditions happen, then the influence of the two diodes doesn't matter anyway !!
As I already mentioned before: I used this principle with success. I used it to protect the input of an inverting OP-AMP, that is preceeded by a tube stage, from turn on- and off- transients within a hybrid bass preamp.
Regards
Charles
Variac,
I don’t know if it will work as a tweeter but Trout Cove Lutherie sells PVDF Piezo Film Sensors.
http://tclutherie.hypermart.net/page4.html
This site has a lot of information on using the stuff which you can get to by clicking the links on the left side.
steve
I don’t know if it will work as a tweeter but Trout Cove Lutherie sells PVDF Piezo Film Sensors.
http://tclutherie.hypermart.net/page4.html
This site has a lot of information on using the stuff which you can get to by clicking the links on the left side.
steve
condenser mic for guitar
I have build mic using this circuits
http://www.linkwitzlab.com/sys_test.htm#Mic
http://sound.westhost.com/project93.htm
I used the wm55 cardiode mic for guitar omni make feedback to easy.
If and body have good tips about condenser mic let me know
best regards jc dk.
I have build mic using this circuits
http://www.linkwitzlab.com/sys_test.htm#Mic
http://sound.westhost.com/project93.htm
I used the wm55 cardiode mic for guitar omni make feedback to easy.
If and body have good tips about condenser mic let me know
best regards jc dk.
PVDF transducers
Hey guys,
I work as a development engineer for Measurement Specialties, the company that manufactures piezo PVDF film. Here is a link to the website:
http://www.msiusa.com/piezo/index.htm
We build numerous custom film products that are used in instrument pickups (guitar, violin, drum, etc.) and speakers. Please don't ask for details, as these designs are typically proprietary to the company who sells the end product.
Piezo film (or disks) can make wonderful instrument pickups, but as they say, the devil is in the details. The film itself is a transducer, that is, it converts mechanical strain into electrical charge. The frequency response is linear to far below and far above the audio range. It is possible to generate over a thousand volts by stretching the film. To make a quality instrument pickup requires careful consideration of the transducer shape, interface materials (including adhesives), and mechanical clamping conditions. All of these will affect the final frequency response!
By all means experiment - if the pickup doesn't sound right, try gluing or clamping it someplace else. Also experiment with adding different materials to dampen it. Some of the best designs have come from a lot of trial and error.
Any pickup will require some form of buffering, and this will also affect the frequency response. Remember, the transducer is basically a capacitor, and any induced strain will produce a charge across the capacitor. We can either use a charge-to-voltage converter (charge amp), or a high-impedance voltage amp (since V=Q/C). Input protection may be necessary, since it is not difficult to generate high voltages.
A voltage amp can be just a simple JFET source-follower or a non-inverting JFET-input opamp circuit. The input impedance and the capacitance of the film set the low-frequency response. A voltage amp is usually placed very close to the transducer to minimize stray capacitance which would lower the signal level.
A charge amp is useful if you want to place the amplifier far from the transducer, since additional capacitance won't attenuate the signal.
Take a look at this document for more technical info:
http://www.msiusa.com/techman.pdf
Craig
Hey guys,
I work as a development engineer for Measurement Specialties, the company that manufactures piezo PVDF film. Here is a link to the website:
http://www.msiusa.com/piezo/index.htm
We build numerous custom film products that are used in instrument pickups (guitar, violin, drum, etc.) and speakers. Please don't ask for details, as these designs are typically proprietary to the company who sells the end product.
Piezo film (or disks) can make wonderful instrument pickups, but as they say, the devil is in the details. The film itself is a transducer, that is, it converts mechanical strain into electrical charge. The frequency response is linear to far below and far above the audio range. It is possible to generate over a thousand volts by stretching the film. To make a quality instrument pickup requires careful consideration of the transducer shape, interface materials (including adhesives), and mechanical clamping conditions. All of these will affect the final frequency response!
By all means experiment - if the pickup doesn't sound right, try gluing or clamping it someplace else. Also experiment with adding different materials to dampen it. Some of the best designs have come from a lot of trial and error.
Any pickup will require some form of buffering, and this will also affect the frequency response. Remember, the transducer is basically a capacitor, and any induced strain will produce a charge across the capacitor. We can either use a charge-to-voltage converter (charge amp), or a high-impedance voltage amp (since V=Q/C). Input protection may be necessary, since it is not difficult to generate high voltages.
A voltage amp can be just a simple JFET source-follower or a non-inverting JFET-input opamp circuit. The input impedance and the capacitance of the film set the low-frequency response. A voltage amp is usually placed very close to the transducer to minimize stray capacitance which would lower the signal level.
A charge amp is useful if you want to place the amplifier far from the transducer, since additional capacitance won't attenuate the signal.
Take a look at this document for more technical info:
http://www.msiusa.com/techman.pdf
Craig
piezo disc acoustic pickups
I have put piezo discs on guitars, banjo, & dobro, with some very good results.
This is what I have observed, but I don't claim to have the ultimate answers.
The body of your instrument acts as an amplifier, filter, and distortion unit. The acoustic sound of your instument comes from an infinite number of point sources on the soundboard and body. All can have varying phase, tone, and amplitude. A single pickup can never reproduce this sound. A pickup near the bridge will give that harsh squacky electric sound and transmit string noise since it is only hearing the string sound like an electric guitar.
More pickups (I am using 3) reduces the amount of gain required and gives a more complex tone which I think sounds more acoustic. Also feedback and string noise are less. Generally I have found it is best to place pickups far away from the bridge (except on dobro and maybe bass). I think my guitar setup is a lot better than commercial pickups I have used and heard but I sure don't know everything.
I can't understand how a bridge transducer can pick up anything but the pure string sound which is not usually what you want. It is the most obvious approach and I tried it first myself. You really want the sound of the box.
A lot more experimentation is neccessary and I would like to know what anyone has learned.
I have put piezo discs on guitars, banjo, & dobro, with some very good results.
This is what I have observed, but I don't claim to have the ultimate answers.
The body of your instrument acts as an amplifier, filter, and distortion unit. The acoustic sound of your instument comes from an infinite number of point sources on the soundboard and body. All can have varying phase, tone, and amplitude. A single pickup can never reproduce this sound. A pickup near the bridge will give that harsh squacky electric sound and transmit string noise since it is only hearing the string sound like an electric guitar.
More pickups (I am using 3) reduces the amount of gain required and gives a more complex tone which I think sounds more acoustic. Also feedback and string noise are less. Generally I have found it is best to place pickups far away from the bridge (except on dobro and maybe bass). I think my guitar setup is a lot better than commercial pickups I have used and heard but I sure don't know everything.
I can't understand how a bridge transducer can pick up anything but the pure string sound which is not usually what you want. It is the most obvious approach and I tried it first myself. You really want the sound of the box.
A lot more experimentation is neccessary and I would like to know what anyone has learned.
There are actually two ways to get the flattest electrical response out of a piezo (the mechanical response will still have resonances, of course). One is to connect the piezo to a very high input impedance amp, as mentioned earlier in this thread. If you use this technique, choose the amplifier input resistance (R) high enough to put the -3db corner frequency with the piezo's self-capacitance (C) at or below the lowest frequency of interest:
R = 1/(2 pi f_lowest C)
This can be hard to do with a physically small piezo, which can have quite a small capacitance, and consequently may require a very large R.
The second method makes use of the fact that the output current of a shorted piezo has a rising +6dB/octave response - basically, every time the piezo is flexed it makes a certain amount of charge, so if it is flexed more times per second (ie at higher frequency) it makes more charge per second, which is to say, it makes more current. Well, if you feed this current into the input of an op-amp wired as an integrator (which has a -6dB/octave falling response) you get a flat output response.
The advantage of the second method is that due to the very low (ideally zero) input resistance of an integrator, hum and electrical noise pickup is often drastically reduced.
Some years ago I spent a few months building active feedback subwoofers, using cheap piezo disks as accelerometers to sense the loudspeaker motion. With a little work I was able to make a sensor that was completely flat within a fraction of a dB from about 10 Hz to around two kHz, when the first mechanal resonance showed up. For my application, that was not an issue, because the woofer I was working with had its first cone break-up mode at about 1 KHz, and so there was no need for more bandwidth than that anyway.
How did I know the sensor was almost perfectly flat? Because the finished subwoofer had a close-miked frequency response flat within about +/- 0.1 dB from about 30 Hz to 250 Hz, fallling off gently above and below that. Measurements were made with my then employers $5000 Bruel and Kjaer measurement microphone and various measurement systems (an AT system 1, for the most part, though I also used MLSSA).
Of course, in-room frequency response suffered from the usual room modes. But that sub still produced *very* tight bass - drum sounds were often too tight with many commercially available music CD's, which had probably been mixed on monitors which had more bass "hangover".
Sad to say, the company I worked for at the time never did anything with my prototypes. Oh, well. Ces't la vie!
-Flieslikeabeagle
R = 1/(2 pi f_lowest C)
This can be hard to do with a physically small piezo, which can have quite a small capacitance, and consequently may require a very large R.
The second method makes use of the fact that the output current of a shorted piezo has a rising +6dB/octave response - basically, every time the piezo is flexed it makes a certain amount of charge, so if it is flexed more times per second (ie at higher frequency) it makes more charge per second, which is to say, it makes more current. Well, if you feed this current into the input of an op-amp wired as an integrator (which has a -6dB/octave falling response) you get a flat output response.
The advantage of the second method is that due to the very low (ideally zero) input resistance of an integrator, hum and electrical noise pickup is often drastically reduced.
Some years ago I spent a few months building active feedback subwoofers, using cheap piezo disks as accelerometers to sense the loudspeaker motion. With a little work I was able to make a sensor that was completely flat within a fraction of a dB from about 10 Hz to around two kHz, when the first mechanal resonance showed up. For my application, that was not an issue, because the woofer I was working with had its first cone break-up mode at about 1 KHz, and so there was no need for more bandwidth than that anyway.
How did I know the sensor was almost perfectly flat? Because the finished subwoofer had a close-miked frequency response flat within about +/- 0.1 dB from about 30 Hz to 250 Hz, fallling off gently above and below that. Measurements were made with my then employers $5000 Bruel and Kjaer measurement microphone and various measurement systems (an AT system 1, for the most part, though I also used MLSSA).
Of course, in-room frequency response suffered from the usual room modes. But that sub still produced *very* tight bass - drum sounds were often too tight with many commercially available music CD's, which had probably been mixed on monitors which had more bass "hangover".
Sad to say, the company I worked for at the time never did anything with my prototypes. Oh, well. Ces't la vie!
-Flieslikeabeagle
contact mic building for dummies
new to forum, dont know what piezos are, but have been wondering about the seemingly endless possibilities of contact mic scenarios for a while......
you did provide instructions in the original thread, which were helpful (if only to learn that this could, possibly, be achievable), but i am neither electronically inclined nor very intuitive.
could you please break down the process of physically BUILDING a contact mic a little more? parts needed, suggestions, etc...
is it not much more than a minor adjustment to a guitar pickup?
any info/instruction/tutelege would be GREATLY appreciated.
thanks, bill
new to forum, dont know what piezos are, but have been wondering about the seemingly endless possibilities of contact mic scenarios for a while......
you did provide instructions in the original thread, which were helpful (if only to learn that this could, possibly, be achievable), but i am neither electronically inclined nor very intuitive.
could you please break down the process of physically BUILDING a contact mic a little more? parts needed, suggestions, etc...
is it not much more than a minor adjustment to a guitar pickup?
any info/instruction/tutelege would be GREATLY appreciated.
thanks, bill
getting a clear tone with piezos, but maybe not the best tone
hey all.
I started playing with the piezos about 5 years or so ago. I had a POS 80 dollar nylon acoustic I used as the test mule.
I glued about 5 of them in and wired and on off switch to each one. I found some combos seemed to work well. but mainly I have to say I liked the 1 inch away from th elow E string loaction under the bridge. I even tried putting a telephone mic in the guitar.
I decided to push it further and build a piezo for each string. I put this on an electric guitar body, and SG copy because the bridge is so big.
so I got an all wood bridge from stew mac, (the arch top model) and cut the piezos into 6 thin strips.
I cut them with scissors, it can be done.
I soldered the wires to the piece first. then epoxied them on because they will break off when you cut it, then cut it to size.
I built 6 strips, and attached them to the back side of the wood bridge, so that the metal would fold over the top of the bridge, and hang down on the backside. this puts all the strings in direct contact with the back of the piezo (the metal part)and the sound travels through it amazingly well this way. it might not have that sweet tone, but it is very clear. Yes the wires hanging off the back were a mess too.
And yes, folding the piezoz over on the bridge cracks the crystals, and makes the part after the bend non amplifiable, because it is broken, but the metal backing side does a good job of sending the vibration to the working part of the piezo.
I split those outputs on the 6 piezos in to sets of twos. meaning I had 2 leads or positives, or red wires comming off those piezos. I intalled 2 sets of micro switches (these have 8 mini on off switces in them and a re really small. similar to the ones inside a garage door open remote) and wired the piezos in stereo.
to be clear, I had a right and left comming off the piezo. each lead ran into an on off switch, then those ran to the left and right output jacks.
this allowed me to put certains strings on the left channel, and certain strings on the right channel. I really liked 135 on the left 246 on right. makes for a cool sound.
I am going to try some more on this. I am attempting to build my own guitar, and I will build the bridge like a classical style bridge, and hope to have all the piezos and wires hidden in the bridge this time, yet have a seperate pieze per each string, and be capable of going stereo output. I had some ideas, I will post more later if they work out.
I also am going to try throwing a mike installed inside the guitar into this. maybe I can get a cool mix of sound. dont know.
Some other ideas were possible triggering of drum triggers with the guitar strings using the piezos. I have a cheap electronic drum set that is triggered with piezos. I have been thinking about hooking it up so the guitar triggers the drums. but that is another things I need to test, and then wonder why I would even do it. lol
hey all.
I started playing with the piezos about 5 years or so ago. I had a POS 80 dollar nylon acoustic I used as the test mule.
I glued about 5 of them in and wired and on off switch to each one. I found some combos seemed to work well. but mainly I have to say I liked the 1 inch away from th elow E string loaction under the bridge. I even tried putting a telephone mic in the guitar.
I decided to push it further and build a piezo for each string. I put this on an electric guitar body, and SG copy because the bridge is so big.
so I got an all wood bridge from stew mac, (the arch top model) and cut the piezos into 6 thin strips.
I cut them with scissors, it can be done.
I soldered the wires to the piece first. then epoxied them on because they will break off when you cut it, then cut it to size.
I built 6 strips, and attached them to the back side of the wood bridge, so that the metal would fold over the top of the bridge, and hang down on the backside. this puts all the strings in direct contact with the back of the piezo (the metal part)and the sound travels through it amazingly well this way. it might not have that sweet tone, but it is very clear. Yes the wires hanging off the back were a mess too.
And yes, folding the piezoz over on the bridge cracks the crystals, and makes the part after the bend non amplifiable, because it is broken, but the metal backing side does a good job of sending the vibration to the working part of the piezo.
I split those outputs on the 6 piezos in to sets of twos. meaning I had 2 leads or positives, or red wires comming off those piezos. I intalled 2 sets of micro switches (these have 8 mini on off switces in them and a re really small. similar to the ones inside a garage door open remote) and wired the piezos in stereo.
to be clear, I had a right and left comming off the piezo. each lead ran into an on off switch, then those ran to the left and right output jacks.
this allowed me to put certains strings on the left channel, and certain strings on the right channel. I really liked 135 on the left 246 on right. makes for a cool sound.
I am going to try some more on this. I am attempting to build my own guitar, and I will build the bridge like a classical style bridge, and hope to have all the piezos and wires hidden in the bridge this time, yet have a seperate pieze per each string, and be capable of going stereo output. I had some ideas, I will post more later if they work out.
I also am going to try throwing a mike installed inside the guitar into this. maybe I can get a cool mix of sound. dont know.
Some other ideas were possible triggering of drum triggers with the guitar strings using the piezos. I have a cheap electronic drum set that is triggered with piezos. I have been thinking about hooking it up so the guitar triggers the drums. but that is another things I need to test, and then wonder why I would even do it. lol
Experience with Piezos
I'm new to this forum so forgive me if I am repeating an application I've used with GREAT results.
Using the inexpensive piezo disk from Radio Shack ($1.49...recently raised to $179) I carefully remove the disk from the plastic housing. I solder a shielded cable to the disk and make a strain relief using pretty heavy, stripped solid core wire. I wrap a small loop around the cable and shape the ends of that loop around the edge of the piezo. If the disk is to be removed repeatably, I'll solder the solid wire around the entire disk to make it sturdier. Then I use a thin coat of epoxy over the top of the piezo to make it truly roadworthy.
In amplifying a violin, cello or upright bass, the BEST place to attach the piezo is on the BACK of the instrument, right where the soundpost hits the back.
The vibration of the bridge is focused at that spot. There is none of the finger noise and squeaks that occur when using a piezo on the bridge.
When using a piezo on the back of the upright bass, you may have to roll off the low end, depending on the construction of the bass.
I ran across this application many years ago. Emerson, Lake and Palmer toured with a symphony orchestra. They needed a way to amplify and record many, many stringed instruments. The musicians were not happy with anything attached to their very expensive instruments. The sight of something put on the bridge was troubling.
So they took the then common Barcus Berry piezo pickup (a little rectangular pickup) and attached them to the back of the instrument as I mentioned before.
The tone possible with this application is remarkable. With my upright I needed to "plug" the F-holes to reduce feedback. I used some heavy black, dense foam (a type used to insulate steam and water pipes in industry). I cut two foam pieces just slightly larger than the F-holes. I trimmed a shallow V channel on the sides of the foam. After the foam was inserted into the F-holes, the result was a very natural appearance.
When mounting the piezo I put a few strips of Scotch 33+ electrical tape down where the pickup would be mounted. The 33+ can be removed without harming the finish.
I then put the piezo on the taped spot using some "putty" used for hanging posters on the wall. There are many sources for this putty, but I've found the blue or yellow types to be the best. The white type doesn't stick well enough.
I then covered the pickup with more electrical tape, and ran the piezo wire down the the bottom of the bass and then ran it behind the tailpiece where it was soldered to a 1/4" jack.
I can't tell you how great it worked. I used this many times over the years on violins in groups I've played with.
I have also used the same type of disk on acoustic guitars. On an acoustic guitar, I put the disk on the treble side of the bridge, on the clear area of the bridge.
This application sounds more natural than an under saddle pickup as it picks up from the top of the guitar as well as the strings.
I used to do sound at a regular "open mike" show at a popular coffee house. Most of the musicians performed with acoustic guitars but most did not have pickups. I made two of the pickup. As one performer played, I would stick a piezo on the bridge. Every player stepped on stage and would plug into a high impedance buffer I built.
It was so simple to deal with the flow of musicians that would play. No feedback problems and the guitar players didn't have to be intimidated by a mike and stand in front of them.
One key to any musical application of piezos is to plug them to a HIGH impedance input. One meg would be the minimum. I would suggest 5-10 meg ohms. Even an under saddle pickup will sound better when buffered by a very high impedance buffer/preamp. Much of the "quack" people don't like when using undersaddle piezos is the result of not using high enough impedance. Once the pickup is bufferec, a much fuller tone results. As you go down in impedance, less bass is produced.
I've used these pickup on all manner of acoustic instruments including guitars, upright basses, mandolins (pickup placed between the bridge and tailpiece), pianos and even a harp.
I worked on a rig for a musician that played harp near a waterfall in the Opryland hotel complex in Nashville. He played on a stage probably 40 feet off the ground in a beautiful "garden" in the hotel. The doors to the rooms surrounded this beautiful area.
The pickup system consisted of 3 piezos attached to the inside ...along the soundboard. We had one problem though. There was a terrible resonance around 250Hz. I found it was the pickup near the lower middle of the harp. We had one pickup near the top, one in the middle, and one in the bass area. The middle was the problem.
Rather than solve the problem with the mixer used for this system. I simply put a small capacitor in series with that piezo to roll off the low end. I think it was .0047uf, but this was many years ago. My memory isn't the best.
The piezos went into individual buffers, and then into a small, but nice mixer. He ran a monitor off the mixer, added some reverb, and sent a signal to the PA in this huge area. He had used mikes for years with inconsistent problems. This system simplified the amplification of his harp.
I don't remember his name, but he was billed as the "Liberace of the Harp." He dressed much like Elvis and even had a tall, black toupe. He was a magnificent musician.
Amplifying a piano had mixed results. Some pianos had just too much pedal noise.
I've been wanting to add piezos to my 5 string fretless bass. It has a Shaller Roller Bridge and I think it could be done with this bridge. I will try cutting up some piezo disks as was describled by an earlier poster.
These things are really fun. I put a Shadow piezo bridge on my main bass (a zebrawood, headless Explorer) back in 1983. They were incredible. I had to roll off the low end in order to make the piezo tone more compatible with the magnetic pickups.
I also had a headless Kramer. I tried putting a couple piezo disks on the underside of the bridge. They added an interesting, metallic tone with great high end and although the tone wasn't useful by itself, it sounded great when mixed with the magnetic pickups.
Our guitar player loved it and described the tone as "Scary!"
I have even had some success putting a piezo disk on the back of a speaker cone. No mikes needed.
FWIW. Barcus Berry actually made a VOCAL piezo pickup. It sounded great but the singers couldn't get used to the cable running out of their mouths.
I've built electronic drum pads that performed much better than the existing Simmons pads of the time.
Nice to find this site.
I'm new to this forum so forgive me if I am repeating an application I've used with GREAT results.
Using the inexpensive piezo disk from Radio Shack ($1.49...recently raised to $179) I carefully remove the disk from the plastic housing. I solder a shielded cable to the disk and make a strain relief using pretty heavy, stripped solid core wire. I wrap a small loop around the cable and shape the ends of that loop around the edge of the piezo. If the disk is to be removed repeatably, I'll solder the solid wire around the entire disk to make it sturdier. Then I use a thin coat of epoxy over the top of the piezo to make it truly roadworthy.
In amplifying a violin, cello or upright bass, the BEST place to attach the piezo is on the BACK of the instrument, right where the soundpost hits the back.
The vibration of the bridge is focused at that spot. There is none of the finger noise and squeaks that occur when using a piezo on the bridge.
When using a piezo on the back of the upright bass, you may have to roll off the low end, depending on the construction of the bass.
I ran across this application many years ago. Emerson, Lake and Palmer toured with a symphony orchestra. They needed a way to amplify and record many, many stringed instruments. The musicians were not happy with anything attached to their very expensive instruments. The sight of something put on the bridge was troubling.
So they took the then common Barcus Berry piezo pickup (a little rectangular pickup) and attached them to the back of the instrument as I mentioned before.
The tone possible with this application is remarkable. With my upright I needed to "plug" the F-holes to reduce feedback. I used some heavy black, dense foam (a type used to insulate steam and water pipes in industry). I cut two foam pieces just slightly larger than the F-holes. I trimmed a shallow V channel on the sides of the foam. After the foam was inserted into the F-holes, the result was a very natural appearance.
When mounting the piezo I put a few strips of Scotch 33+ electrical tape down where the pickup would be mounted. The 33+ can be removed without harming the finish.
I then put the piezo on the taped spot using some "putty" used for hanging posters on the wall. There are many sources for this putty, but I've found the blue or yellow types to be the best. The white type doesn't stick well enough.
I then covered the pickup with more electrical tape, and ran the piezo wire down the the bottom of the bass and then ran it behind the tailpiece where it was soldered to a 1/4" jack.
I can't tell you how great it worked. I used this many times over the years on violins in groups I've played with.
I have also used the same type of disk on acoustic guitars. On an acoustic guitar, I put the disk on the treble side of the bridge, on the clear area of the bridge.
This application sounds more natural than an under saddle pickup as it picks up from the top of the guitar as well as the strings.
I used to do sound at a regular "open mike" show at a popular coffee house. Most of the musicians performed with acoustic guitars but most did not have pickups. I made two of the pickup. As one performer played, I would stick a piezo on the bridge. Every player stepped on stage and would plug into a high impedance buffer I built.
It was so simple to deal with the flow of musicians that would play. No feedback problems and the guitar players didn't have to be intimidated by a mike and stand in front of them.
One key to any musical application of piezos is to plug them to a HIGH impedance input. One meg would be the minimum. I would suggest 5-10 meg ohms. Even an under saddle pickup will sound better when buffered by a very high impedance buffer/preamp. Much of the "quack" people don't like when using undersaddle piezos is the result of not using high enough impedance. Once the pickup is bufferec, a much fuller tone results. As you go down in impedance, less bass is produced.
I've used these pickup on all manner of acoustic instruments including guitars, upright basses, mandolins (pickup placed between the bridge and tailpiece), pianos and even a harp.
I worked on a rig for a musician that played harp near a waterfall in the Opryland hotel complex in Nashville. He played on a stage probably 40 feet off the ground in a beautiful "garden" in the hotel. The doors to the rooms surrounded this beautiful area.
The pickup system consisted of 3 piezos attached to the inside ...along the soundboard. We had one problem though. There was a terrible resonance around 250Hz. I found it was the pickup near the lower middle of the harp. We had one pickup near the top, one in the middle, and one in the bass area. The middle was the problem.
Rather than solve the problem with the mixer used for this system. I simply put a small capacitor in series with that piezo to roll off the low end. I think it was .0047uf, but this was many years ago. My memory isn't the best.
The piezos went into individual buffers, and then into a small, but nice mixer. He ran a monitor off the mixer, added some reverb, and sent a signal to the PA in this huge area. He had used mikes for years with inconsistent problems. This system simplified the amplification of his harp.
I don't remember his name, but he was billed as the "Liberace of the Harp." He dressed much like Elvis and even had a tall, black toupe. He was a magnificent musician.
Amplifying a piano had mixed results. Some pianos had just too much pedal noise.
I've been wanting to add piezos to my 5 string fretless bass. It has a Shaller Roller Bridge and I think it could be done with this bridge. I will try cutting up some piezo disks as was describled by an earlier poster.
These things are really fun. I put a Shadow piezo bridge on my main bass (a zebrawood, headless Explorer) back in 1983. They were incredible. I had to roll off the low end in order to make the piezo tone more compatible with the magnetic pickups.
I also had a headless Kramer. I tried putting a couple piezo disks on the underside of the bridge. They added an interesting, metallic tone with great high end and although the tone wasn't useful by itself, it sounded great when mixed with the magnetic pickups.
Our guitar player loved it and described the tone as "Scary!"
I have even had some success putting a piezo disk on the back of a speaker cone. No mikes needed.
FWIW. Barcus Berry actually made a VOCAL piezo pickup. It sounded great but the singers couldn't get used to the cable running out of their mouths.
I've built electronic drum pads that performed much better than the existing Simmons pads of the time.
Nice to find this site.
Glad to read your reply here.
The mouth system you spoke up is triggering some ideas in my head. hmm... any more info on how this peice worked?
I found another spot on the headstock, that seemed to pick up sound pretty well too. just above the nut, on the back of the headstock. I had an old guitar that I cut a grove into the back of the neck and ran the wire into the neck and filled it so there is a lack of wire getting in the way.
I also seen those brass pieces they make to put on the headstocks to create more sustain. I was wondering about sandwiching it inbetween that, maybe it would change the tones some.
I have been debating on installing the piezo's on each string at the bridge and the nut. this should create some odd sounds. plus the notes on the other end of the strings.
I am looking at installing tons of piezos into a guitar, and giving them thier own on off switches, and see what kind of tones I can get out of it. what works, what doesn't. basically giving up a guitar to experiment on.
How do you go about boosting the high impedance input?
The mouth system you spoke up is triggering some ideas in my head. hmm... any more info on how this peice worked?
I found another spot on the headstock, that seemed to pick up sound pretty well too. just above the nut, on the back of the headstock. I had an old guitar that I cut a grove into the back of the neck and ran the wire into the neck and filled it so there is a lack of wire getting in the way.
I also seen those brass pieces they make to put on the headstocks to create more sustain. I was wondering about sandwiching it inbetween that, maybe it would change the tones some.
I have been debating on installing the piezo's on each string at the bridge and the nut. this should create some odd sounds. plus the notes on the other end of the strings.
I am looking at installing tons of piezos into a guitar, and giving them thier own on off switches, and see what kind of tones I can get out of it. what works, what doesn't. basically giving up a guitar to experiment on.
How do you go about boosting the high impedance input?
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