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Most DIY enthusiasts who are interested in audio gear are familiar with the standard “tin can mic” (or variations thereof), in which a piezo disc is taped onto the bottom of a tin can and then plugged into a high impedance voltage amplifier, like a guitar amp. These types of microphones are nice because they are so easy to make, but they are quite limited in most other areas, including bandwidth, microphonics, signal to noise ratio, impedance matching, and cable driving. These issues usually result in a very noisy and brittle sounding microphone. So out of frustration with these limitations, we created the “New and Improved Tin Can Mic” -- the standard tin can mic taken to the next level! Using common household items along with a simple circuit, this mic has a tonality similar to the original tin can mic (for all you Tom Waits fans), but improves upon nearly every other feature. The heart of the mic is the Cortado contact microphone which consists of a tiny phantom powered circuit which creates a balanced output from a piezo disc. This circuit provides a high impedance to the piezo disc, but also provides a low output impedance to match a mixing console input. By properly matching the input and output impedances we achieve a much wider bandwidth than the original tin can mic. The fact that the output is balanced provides a very high signal to noise ratio, and it allows for a long microphone cable to be used without signal degradation.

Another improvement we've made to the standard can mic is that we've added a styrofoam cup as a mechanical resonator. The cup floats inside of the tin can via rubber bands, which helps keep microphonics and feedback (in live performance situations) manageable. Another benefit of using a floating mechanical resonator is that it's easy to mod the mic to change its tonality. We can easily alter the resonant frequency of the mic by changing the mass of the cup, or we can emphasize a higher resonant harmonic by adding a vibration node to the cup.

The Cortado contact mic in itself is capable of a very wide, flat bandwidth which is suitable for use as a contact mic in lots of recording situations, on anything from a piano soundboard to a plate reverb. The circuit is fairly simple and can be built from common parts using the schematic given in this Instructable. As a service to the DIYer, the Cortado is offered as a kit from Zeppelin Design Labs. The kit includes the circuit board as well as all the other parts (including matched FETs) to make the Cortado into a variety of configurations for different applications. For this instructable, we will document the construction of the Cortado kit for its application in the “New and Improved Tin Can Mic.”


Every track in this song was recorded with only the Cortado contact mic. The vocals were recorded using the Cortado configured as the "New and Improved Tin Can Mic" described in this Instructable. For those interested, the band in this recording is Ami Moss and the Unfortunate. Recording notes and more info can be found here.

PARTS NEEDED:

  • Tin (steel) can (typical #1 can)
  • Styrofoam cup (12 oz)
  • 3 rubber bands (medium sized)
  • 5” cross stitch or embroidery ring
  • #6-32 2” Machine Screw
  • 2x #6-32 Nut
  • #6 Lock washer
  • 3/8” 16tpi nut
  • Mic stand adapter with 3/8” 16tpi threaded shaft
  • Cortado Contact Mic kit (or these parts):
    • Piezo disc (with 6” 30awg wire leads)
    • PCB (or bread board)
    • 1x male XLR jack with 12” balanced mic cable
    • 2x matched 2N3819 FETs
    • 1x unmatched 2N3819 FET
    • 4x 3.3M 1/4W 5% resistors
    • 3x 150 ohm 1/4W 1% resistors
    • 1x 1.5K 1/4W 5% resistor
    • 3x 220pF film capacitors
    • 4” 22awg black ground wire
    • ~1sq”double stick tape
    • 12 mm nylon standoff
    • 2x M3x6mm screws
    • Rubber grommet (big enough for the mic cable)
    • 1x Zip tie

TOOLS NEEDED:

  • soldering iron
  • digital multimeter
  • drill
  • drill bits (9/64, 3/8)
  • sandpaper (~150 grit)
  • needle nose pliers
  • wire strippers
  • #2 Philips screwdriver
  • can opener (that can remove the top rim of a can)
  • diagonal cutters or wire snips
  • ruler
  • scissors
  • X-acto knife or razor blade
  • Fine tip permanent marker
  • Center punch or sharp nail for marking holes through the template

SUPPLIES

  • Solder, 60/40 rosin core, the smaller diameter the better
  • Black nylon stockings
  • Epoxy
  • Sticky tack (the stuff you use to hang posters on the wall)
  • Tape (masking or Scotch)
  • Rubbing alcohol or Isopropyl alcohol
  • Small rag or paper towel

Step 1: The Cup

  1. With your X-acto knife or razor blade cut off the top rim of the 12 oz styrofoam cup. Try to make the cut as smooth as possible. Set the rim aside until later(1).

  2. The next step creates a cup that is 2 11/32” tall. There are probably several ways to do this but here's how we did it. Use your ruler to measure 2 11/32” (or 6cm) from the bottom of the cup and mark the cup(2). Rotate the cup a few degrees and repeat this step. Continue marking small dashed lines until you make your way all around the cup(3). Connect all the dashes with a solid line(4). Use your X-acto knife or razor blade to cut the cup at this line(5). Set this cup aside until later.
<p>Could you use this microphone as a surface microphone, like to control the room? For instance, I put on a wall. I wanna cut the reflection of this wall. So I record, and invert the phase of the vibrations that the Cortado picks up. Would it be efficient? I know a surface mic is a kind of contact mic. I guess I'd have to try.</p><p>FANTASTIC warm, vintage, raw roots sound from this mic!</p>
Surface mic... hmmm... We think you just need to try. As my design partner put it, &quot;It would be easier to try it out than to think about it.&quot;
<p>Hello, how are you? In the article is available the figure of the location of the components and their values. There is also some links image, from the wiring diagram, so I can do the icb. I loved the project, I would be very happy if you could be helping me!</p>
<p>When I review the article, all the illustrations are visible and all the links work properly. Figure 1: Component Locations and Values is correct. The Schematic is available as a PDF download at the bottom of Step 2.</p><p>We have improved the Cortado since publishing the article. If you buy a kit from us, you will discover a different circuit and different PCB. For use as a tin can microphone, the original circuit shown in the article is better.</p><p>Does this answer your question? How else may I help you?</p>
Thanks for replying, my mistake was when I clicked on &quot;see all the steps&quot; where the PDF did not appear. I would like to buy the kit, but since I am from Brazil, I can not be buying at the moment, but certainly in the future. Thanks for the answer!
<p>This is one of the coolest Instructables I've seen yet! I intend to make this some time in the next year. I'll also keep up with developments in the design. Excellent!</p>
Thanks for your encouraging remarks! We have a whole series in mind of goofy, strange and wonderful applications of the Cortado contact mic, including other (simpler) vocal mic ideas. Be sure to subscribe.
Nice, But if I have to guess, Doesn't the metal amplify the treble sounds more?
<p>Well, the cup and the can will resonate at certain frequencies characteristic to their materials. You can listen to the vocalist in the demo song, who used the actual, self-same mic you see in the Instructable, and judge for yourself if it's too treblie for your taste. We just published <a href="http://www.diyrecordingequipment.com/blogs/news">this article </a>on Tin Can Mic design generally, and it emphasizes that you can use a LOT of different things for the cup and the can, and each combination will give you a different sound.</p><p>If you make a mic that does overemphasize a particular frequency, you can experiment with different damping measures to &quot;tune&quot; it. That's what we are doing with the sticky-tack in the bottom of the cup in this Instructable. You can stick blobs of clay on the tin can in various places to kill some of its high frequency response if necessary.</p>
<p>I have a question: Would I be able to replace the amplifier cable with, say, a USB cable for YouTube recordings?</p>
Well, no; the mic produces an analog signal, and a USB port receives a digital signal. You need something in between to power the Cortado and convert its signal to digital, like the Zoom UAC-2 or similar. Of course, you could buy ten Cortados for the price of one Zoom, so here's a better idea: In a few months we plan on releasing the Espresso mobile phantom power unit. For under $50, this kit uses a 9V battery to power your Cortado, AND has an option to unbalance the signal so you can fit the cable with a mini-jack and plug it straight into the little round &quot;mic&quot; input on the back of your PC. You can see a picture and read a little more about it in our <a href="http://us10.campaign-archive1.com/?u=3894ef7b5454864c846b68140&id=c36ca33256" rel="nofollow">Fall Newsletter.</a><br> <br>
<p>Thanks! You answered my question perfectly.</p><p>GR8 M8 I R8 8</p>
<p>Behold, the Espresso. With a cable that has a 1/4&quot; jack on one end and the appropriate mini-jack on the other, you can plug your Tin Can Mic straight into a PC, laptop or tablet.</p>
I used a curtain rod holder the i modified for the shock mount holder but other than that...great character mic! Listen for it in the new Boo Bunny Plague: Rock and Rouge game on Steam coming in may of 2016! Thanks Zeppelin Design Labs for reaching out and making a great instructable!
<p>Great use of the curtain rod holder! It looks great! We look forward to hearing it on the new Boo Bunny Plague game. It's really great to see that you're making good use of your Cortado tin can mic...and we look forward to hearing more recordings with it!</p>
<p>I love it, but won't the rubber bands get brittle over time? Maybe substitute them with hairbands or sewing elastic.</p>
<p>Use ranger bands (they won't look so good). Or find some small steel springs like in the old carbon mike -- great looks, don't know about the dampening characteristics.</p>
<p>Thanks for the tip. I never heard of ranger bands, but a quick Google shows me that they're quite awesome. Not to mention very cheap in the bicycle country The Netherlands where I live. But how far can you stretch these bands, I guess that depends largely on the width of the band?</p>
<p>That's probably a good point. We haven't had ours long enough for the rubber bands to get brittle yet, but they may in a few years. Sewing elastic seems like it would be a good mod. Thanks for the tip!</p>
Even sewing elastic degrades over time. See: those favorite socks or underwear that just aren't what they used to be. :-(<br><br>As a sewer, I've gone to an elastic stash only to have it basically shatter in my hand because it's been stashed too long.
<p>I really like this, though I have to say, wouldn't it sound tinny? *Duh dum tss* Couldn't help it, I really like it and I'm going to run it by the band, see if the singer wants one. </p>
<p>love this!</p>
<p>Great character mic! </p><p>It makes me wish I was still recording. </p>
<p>Record again! With this guy, you can record 'most ANYTHING! As a contact mic, you can record the refrigerator, the fish tank, the coffee pot, the engine block, the bird house, the rabbit nest, the ant hill, the...</p>
Fantastic article! Thanks
<p>You're welcome. Nice dog.</p>
<p>That mic is perfect </p>
<p>My! Now, you see, we are indeed pretty proud of it, but, you know, every parent thinks his child is perfect. I am grateful for this independent confirmation of what we suspected all along!!</p>
<p>Thank you very much for this instructable!</p>
<p>In step 4 to say to print the template full size. What template, or is it only available if you buy the kit?</p>
<p>Opps! Sorry, we forgot to upload the template....Fixed now.</p>

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Bio: Zeppelin Design Labs combines the talents of two engineers: Brach, an expert audio products designer; and Glen, a veteran project manager. Our team also includes ... More »
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