Make your own contact mics

[Thee Alex]

A quick guide to making a contact mic.

First, get down to Maplin and buy a piezo transducer or two (PIEZO TRANSDUCERS) they cost less than a quid. Then get some doublesided tape and some gaffer tape (if you've not got some already). You'll also need either a guitar cable you're willing to sacrifice or (and I think this is better) an audio extension cable that has a female connector at one end.

A piezo transducer, on my bed a few minutes ago

Strip the wires back on the transducer and the cable you're going to attach it to (if you're using, as I did, a stereo extension cable then you just wire the red to the red, white to the black (or black to black) and ignore the yellow inside the stereo cord).

When it comes to connecting wires up I'm not a big fan of solder so I tend to twist the copper wires together, tape them so they don't short, then tape the two parts to make a new 'cover' for the cable.

shitty diagram of wiring connections

Using your doublesided tape, attach the pickup where you want it to be, then secure your wires with the gaffer tape - you don't want to be soldering these things back together all the time (as Sian from Wings & Claws spends half her time doing with hers)

And that's it.

Jack socket coming from thumb piano


Wiring taped to back, note doublesided tape crud on pickup from incorrect mounting incident


Front view of now easily amplified thumb piano

Tips: the 'blank' side of the pickup should be face out. On a thumb piano (or similar) placing the pickup on the underside beneath the bridge is NOT a good idea, the board vibrates more at the edge nearest to you when playing so place it where the vibrations are. Don't completely restrict the movement of the pickup, a little give with allow it to vibrate more. The part where the wires are soldered on is the one place that benefits from some pressure when being attached to your instrument.

This will work straight into an amp, but the volume will need to be up. In Wings & Claws we've been putting all the contact mic'd stuff through a mixer to pre-amp it.

[Rosco the Bosco]

Can you stick up some audio examples?
Maybe the piano recorded with a mic VS the piano with the pickup?

[Thee Alex]

You can hear the piano recorded with the pick-up at wingsandclaws.co.uk (the first part of the track there is recorded live via a mixer).

If you're after fidelity then a powered mic is going to always be better, but in a live situation the piezo wins out every time.

And at less than a fiver for the basic parts, and less than 10 minutes needed to make it, the piezo mic seems pretty good.

[Rosco the Bosco]

Cool thanks.

[mrlizard]

Originally Posted by Thee Alex

A quick guide to making a contact mic.

First, get down to Maplin and buy a piezo transducer or two (PIEZO TRANSDUCERS) they cost less than a quid. Then get some doublesided tape and some gaffer tape (if you've not got some already). You'll also need either a guitar cable you're willing to sacrifice or (and I think this is better) an audio extension cable that has a female connector at one end.

A piezo transducer, on my bed a few minutes ago

Strip the wires back on the transducer and the cable you're going to attach it to (if you're using, as I did, a stereo extension cable then you just wire the red to the red, white to the black (or black to black) and ignore the yellow inside the stereo cord).

When it comes to connecting wires up I'm not a big fan of solder so I tend to twist the copper wires together, tape them so they don't short, then tape the two parts to make a new 'cover' for the cable.

shitty diagram of wiring connections

Using your doublesided tape, attach the pickup where you want it to be, then secure your wires with the gaffer tape - you don't want to be soldering these things back together all the time (as Sian from Wings & Claws spends half her time doing with hers)

And that's it.

Jack socket coming from thumb piano


Wiring taped to back, note doublesided tape crud on pickup from incorrect mounting incident


Front view of now easily amplified thumb piano

Tips: the 'blank' side of the pickup should be face out. On a thumb piano (or similar) placing the pickup on the underside beneath the bridge is NOT a good idea, the board vibrates more at the edge nearest to you when playing so place it where the vibrations are. Don't completely restrict the movement of the pickup, a little give with allow it to vibrate more. The part where the wires are soldered on is the one place that benefits from some pressure when being attached to your instrument.

This will work straight into an amp, but the volume will need to be up. In Wings & Claws we've been putting all the contact mic'd stuff through a mixer to pre-amp it.

Thats pretty cool, i don't get why you don't just solder the wire rather than twisting it together. You're not gonna get a good connection and it'll be easily pulled apart. Any particular reason why you don't like solder?

[Keerin]

I would hazard a guess that it is simply because not everyone has or has access to a soldering iron/kit. Makes it cheaper if you just twist the wires together. That's probably it.

[Thee Alex]

Indeed

The connection with the wiring twisted and taped is no worse a connection than a soldered one in terms of signal getting through - it's either connected or it isn't. Also using tape is very quick and can be undone a lot more easily.

Solder is useful for loads of things, I just prefer to use 'twist n tape' on projects where I'm trying to get something done quickly and in a way that can be easily reversed.

[mrlizard]

Originally Posted by Thee Alex

Indeed

The connection with the wiring twisted and taped is no worse a connection than a soldered one in terms of signal getting through - it's either connected or it isn't. Also using tape is very quick and can be undone a lot more easily.

Solder is useful for loads of things, I just prefer to use 'twist n tape' on projects where I'm trying to get something done quickly and in a way that can be easily reversed.

Don't mean to nitpick, because i think the whole thing is a great idea. But if you just twist copper wire together eventually it'll become intermittent. If you move it around it'll crackle and bang. If you're not a fan of soldering it might be worth using chocolate blocks or something else that'll give you stronger connection, they cost about 2p as well.

Still not ideal though, whats the big deal about soldering! everybody knows somebody thats got a soldering iron. Why half arse an otherwise pretty cool thing.

[Thee Alex]

Where that one is 'twist n tape'd it'll never move, as the connection in the part of the cable that's taped hard to the body of the thumb piano.

I know what you're saying Robin, but I can only go from experience...I've been twisting and taping for over ten years now and still have cables that are totally fine/unbroken/crackle free years after they've been done. These include cables which have been heavily gigged in that state.

Soldering is a piece of piss, but it's not often that you'll have a soldering iron and some solder kicking around at a gig whereas gaffer tape is going to be everywhere. A quick, easy, stable fix is good enough in most cases, and (as I've seen) often lasts for years and years.

[Thee Alex]

Anyway, concentrating on the method I used for connecting the cables is to concentrate on a completely inconsequential part of the project

Contact Mic for less than a fiver y'say?

[Thee Alex]

Audio examples -

First up I recorded my thumb piano using the built in mic on my laptop. Had to play the piano hard to get a loud enough recording.



Then I plugged the contact mic into the line in on the laptop, keeping the exact same settings in Live. I had to play the thumb piano VERY softly to avoid serious clipping as the pick up puts out loads of signal



Correctly pre-amped I think the contact mic would be very usable for a recording (though I'd personally record a thumb piano with a normal mic if it were for something that didn't require lots of effects being applied to the final piece). When it comes down to live use the contact mic is perfect and is far better than just playing the piano into a nearby vocal mic.

[mrlizard]

sounds cool!

[TheHolyWeed]

so you'v bought a piezo transducer and used it as a piezo transducer mic....