Crystal Mic, almoust from scratch

[richon]

Hi,

after a lot of playing to test and build a LOFI sounding Mic using a CARBON MIC capsule i decided to use it as a diaphagm to exite a Crystal (ceramic piezoelectric) and test how it sounds.

First the pictures (taking the parts of a old telephone carbon mic):

















then I put the carbon mic diaphragm over the Crystal (besides the noises for being held only by hand over the crystal and my bad harmonica playing)...

...finally a video of how it sounds : http://www.youtube.com/watch?v=IGiks6WemVA

[richon]

and this is how it sounds LINE/mic preamp ( http://www.mediafire.com/?jzktntohnxz  )

it isn't the same sound, 'cause with the Crystal /ceramic piezo it has HIGH impedance output, good for guitar amps, bad for preamp/mic preamps signal

[Brymus]

hey thats pretty neat Richon.
Nice to know your a harp player ,that sounded pretty good to my ears.
What did you like/dislike about it ?
Does it meet your goals ?

[richon]

hey thats pretty neat Richon.
Nice to know your a harp player ,that sounded pretty good to my ears.
What did you like/dislike about it ?
Does it meet your goals ?

thanks for the "HARP player" but I need to learn a lot left to be called "harp player"

I really like the way it overdrives soflty , how it hasn't enough bass (specially by holding it by hand to work), still think that with a small wind-shield it will amplify less highs to let the amp distort by volume

so far, so good....

will try to record a better take with mics to the amp, hopefully that don't show the sound of the HARP to the camera, just GOOD MICs.

and a way to fix the CARBON MIC CAPSULE to the CRYSTAL PIEZO so it won't get loose or produce any handling sounds

[petemoore]

  Thank you for sharing !
  Way to cobble a microphone, these little peizo's are fun !

[richon]

fun and easy to use:

the have very high impedance: perfecto to connect directly to an TUBE AMP

[Skruffyhound]

Hey, I almost missed this post!
Great idea, it opens up some interesting avenues for experimenting with piezos.
I've been playing with different mics all week and especially with piezos, they give such a good response for no money and no extra circuitry, but I've been wondering how to get something out of them without picking up every little string scratch/tap on the body and also how to use them with other instruments.
Thanks for posting.
- Aston

[petemoore]

but I've been wondering how to get something out of them without picking up every little string scratch/tap on the body and also how to use them with other instruments.
  This is generally the second step with these 273-083's from RS...or any other source of similar/same peizo.
  It involved buffer [doesn't help scratch/taps], booster [makes it louder, only if needed] another booster [might need 12 or more volts?...same as the first booster..if needed].
  One LM3875 SE amplifier gets 20v from a battery and the peizo barely was noticable as working, the first booster brought it up but didn't push near hard enough...
  The second booster was also a simple NPN [both were LPB-like], but ended up as a Jfet [not quite as much boost, but still plenty] with a "HF sheen cap" on the Source bypass resistor.
  Then a 'tone control' [LP filter = 100k > .1uf] was needed and helps with the scratching somewhat.
  Where..is paramount, but how the peizo's mounted matters also.
  I have a Moustache' bridge which fascilitated easy slide-spring piece of rosewood I shaped perfectly...clamped between: Under the bridge/over the top-spruce.

[richon]

the idea to use them as MICS is that the CARBON MIC DIAPHRAGM moves and pushes the Piezo/crystal so this will traduce more and a lot better sound

it hace high impedancia and really GREAT OUTPUT as is!

[petemoore]

Very nice voltage output, very easily loaded down if asked for current, very easily interfaced with a buffer that will deliver current.

[TimWaldvogel]

how could you wire a peizo for a guitar? i have a guitar i converted from having wo singles and a humbucker to just one humbucker and one volume knob. i would like to put a mini toggle and turn on and off a piezo thats placed under the pickguard. cause its got such a natural resonance coming from underneath the hollow area under the pickguard. PM me if you dont wanna pout it on the thread

[Skruffyhound]

      Tim,the piezos I'm playing with have two wires attached, solder them to a jack socket, tip/sleeve and connect the socket with a normal guitar cable to your amp input. They make sound whichever way round you attach the wires but I understand that changing the connection around also changes the phase of the signal, so if you are planning to use two or more then probably best to connect them the same so they have the same phase and won't cancel each other out when combined. Simple as that.
      Pete, I'm finding that they are plenty loud just as they are. I had fun with my kids last weekend just holding a piezo on their chests like a stethoscope and listening to their hearts through the amp.
      I may consider a little box with some tone controls, but I'm also thinking about building a fixed Q graphic equalizer and maybe buying a mixer/soundcard combo that could solve some other issues for me. Lets see what happens.

[23]

Hey Id really like to do this, but have no idea whats going on after he disassembles the capsule.....as i dont know crap about mics or peizos.

any info?

[petemoore]

  Connect the wires to a jack, plug a cable to connect peizo to amp.
  For best response a Jfet buffer, any buffer, drives current, if the input is very high impedance [like say that of a buffer] the full frequency response can more cleanly be drawn from the element.