EEVblog #602 – Introduction to Microphones

In the first of a series of videos tutorials on microphones, Doug Ford, former head designer at Rode Microphones explains the basics of how microphones work, the different types – carbon, dynamic, ribbon, condensor/electret, and how the omnidirectional pattern works.
Also, the internal construction of a high end measurement microphone.

Discuss on the Forum HERE

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  1. A great work in progress.I can not wait for the next one.Cheers!Excellent

  2. Come on now Dave, we’re not stuck on the entire “non-metric” system. The three main non-metric units we like here in the US are mph for speed, pounds for weight, and degrees farenheit for temp for no other reason than that we’re used to the scaling. Every American knows what Celcius is, but if you tell them it’s 40 degrees out, you’ll see them go for their coat! But when I ask my students what the acceleration due to gravity is, they all tell me “9.8!!!” and I say 9.8 what?… Meters per second per second.

    I guess I’m kind of the same way though. I’m so used to hearing how the rest of the world has moved entirely to metric system that I just assume you all use metric for everything. One time, when I was using my dad’s ’83 Porsche (nice German car) I went to adjust a limit screw on the throttle body and when I was loosening the lock nut, I broke the screw. Oops! I pulled out my metric tap and die kit and began trying to find the screw’s thread pitch and diameter. Half an hour later I still messing with it, it finally occured to me, try SAE, you know, that stuff with inches! Sure enough, I found the size, got the screw and replaced it.

    Anyway, I enjoyed the video. GOOD TOPIC! I am a proud owner of a Shure SM58 and SM57 mic. They are great mics… workhorses and reliable. Next time maybe you can go into why the 3 conductor XLR cables used for low impedance mics like the Shure SM58 are so much more immune to noise (or at least seemingly so) than coaxial cables. It’s actually that they are low impedance and have a mechanism for canceling the noise that they do pick up.


  3. On Brüel & Kjaer’s website one can find good papers, for example :

  4. Here in the UK, kids are taught in school the metric system – and use inches and feet to communicate with their parents, so Imperial will be gone soon.

    I found the video refreshing – somebody who clearly knows his stuff being honest and getting the info ration that matters across, while missing out the common bits that confuse.

    I liked it!

  5. Thanks Doug and Dave, that was one more great video from you though it ended too early. As a (crappy) musician I’m looking forward for the following videos on the subject or anything related to audio and music. Thumbs up!

  6. Hey Dave, can you get your hands on this (Sony’s large ereader suitable for tech docs) PLEASE?

    Some commenter said it should be launching either in US or globally soon.

  7. @ ~14 minutes:

    Corroded silver has the same (ish) parameters as silver. aka: The electrical parameters won’t change. This is neat for high frequencys (RF), due to the skinning effect.

    It’s a lot harder (vacuum chamber) to sputter gold, then to electroplate silver. The latter can be done at home in your Lab at the cost of silver and electronic garbage.

    So my question is:
    (Why) would silver be a problem within microphones?

    • “It’s a lot harder (vacuum chamber) to sputter gold, then to electroplate silver.”

      Why would you want to put electoplated silver on top of sputtered gold? Why not just one or the other?

      • Sorry, my bad. I’m not a native English speaker.
        s/then/than/ (RegEx search/replace, for the non software guys)
        I’m not trying to plate silver over gold, that would be totally useless and comes at it’s price.

        I was referring to the video, which states that silver corrodes, and therefore people use gold in microphones.

        Would silver oxide change the frequency response (as in acoustic) of the microphone over time (as the oxide forms)? Or what would be the reason to prefer gold above silver in a microphone?

  8. An idea crossed my mind. In a condenser mic, couldn’t you eliminate the connection to the wobbly diaphragm, and then use use two plates behind it to make two capacitors in series?

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