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USING YOUR CONTACT MICROPHONE
There are about as many applications for the Cortado as there are sound sources in the world. Please
read this section carefully to learn how to get the most from your contact mic and how to use it properly.
With some basic supplies and a little creativity your Cortado contact mic should give you years of
great service.
MOUNTING
One of the most important things to know when using piezoelectric devices is how to mount them to
obtain the best pickup. If your piezo disc is mounted incorrectly most likely it will have a very narrow
bandwidth (meaning it won’t pick up a wide range of frequencies), have a low signal to noise ratio,
and in a worst-case scenario, get damaged. Piezo electric devices pick up the best when they are
very tightly coupled to a vibrating surface. The more securely mounted they are, the better. The best
place to mount the piezo disc is on a smooth, flat surface, where the surface area of the disc can make
the most contact with the vibrating material. The double-sided tape provided with your kit is excellent
for permanently installing the disc on a flat sound source. If non-permanent installation is required,
then just taping the piezo disc to a sound source with painter’s tape also works sufficiently; just make
sure it can’t rattle or vibrate against the surface and it is held securely. Sticky-tack (the stuff used to
hold posters on the wall) also works well for non-permanent installations. If you need to mount it on a
round or uneven object a plastic clamp works well, but do not allow the piezo disc to bend at all; this
will damage the disc. The disc is rather fragile and the ceramic element can crack if it is not handled
carefully.
The circuit board is intended to be mounted inside a shielded enclosure, such as the tin can furnished
with the kit. However, any conductive container to which you can attach the ground wire will work,
such as a tuna can or soup can. A die-cast aluminum box (like the Hammond 1590 series) would also
work well as long as you can figure out a way to attach the ground wire (such as a solder lug attached
via a nut and bolt). The PCB is easy to mount with the stand-off and the two screws it comes with, but
it’s not necessary to use them. If the container you use is too small to mount the board via the standoff,
it is possible to just wrap the board in electrical tape and leave it floating (not anchored to anything).
In the container you use, you must drill two
3
/
8
” holes for the XLR cable and piezo disc cable. Two
rubber grommets are provided in the kit for mounting in the holes around the cables. Two zip ties are
also provided in the kit to tie around the cables on the inside of the container to provide strain relief.
USING MULTIPLE MICS AT ONCE
Some applications may require more than one contact mic being used on the same source. This works
very well for many musical instruments particularly stringed instruments and pianos. The main thing
to be mindful of in these situations is the phase of each microphone. In most situations the relative
phase of all mics should be the same. This means that a positive impulse from the sound source will be
picked up as a positive (not negative) signal from all the microphones. If you followed these assembly
instructions properly, then any Cortado you build should be in the same relative phase.
