The View Up Here

Random scribblings about kites, photography, machining, and anything else

Flush Mount Mic Bodies

Posted by Tom Benedict on 06/09/2015

In my previous post I mentioned that the mic bodies I’d made were coloring the sound of the mics in the SASS. I figured in a couple of weeks I could make new mic bodies that would mount the BT-EM172 capsules flush with the end, and recover some of the bass I was missing with the existing bodies.

Myeah… I couldn’t wait that long. After work Friday I made new ones.

Flush Mount Mic Body

I wanted to make them with the same form factor as the original ones I’d made out of aluminum. That would let me mount them in the SASS without having to modify it. This started life as a 3/4″ black Delrin round, turned down to the right outside diameter and bored out. No screws in this design. I prototyped it on my mono mic, then made bodies for the SASS mics. Everything loads from the front, and then the mic is pressed into the body. It’s a pretty snug fit, so I hope I don’t have to take them out any time soon.

SASS - Flush Mount Mic

The new mic bodies went in just fine, and now I’m finally operating my SASS as a stereo boundary microphone array. YAY!

I’m holding off on replacing the bodies on the pair of lav mics I made. Without the screen mesh and the rubber shock mount, there’s not as much need for room inside the mic body. I could make this a lot less chunky and a lot more like a lavalier. I want to think on the design before cutting.

Meanwhile everything’s back together. Time to get out and record more waves!

– Tom

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3 Responses to “Flush Mount Mic Bodies”

  1. Mike said

    Hi again Tom,

    Sorry for commenting on such an old post. Your various writings on the EM172 capsules have been very helpful.

    I wonder if you would mind briefly sharing details (for someone without a workshop/metalworking background) the specs for this version of your mic casing? I’d quite like to try making something like this myself as a pet project.

    Do you have the capsule itself inside one of the little rubber sleeves before putting it into the metal housing? Is that a little sliver of circular stick foam stuck to the outer face of the capsule?

    Many thanks,
    Mike

    • Tom Benedict said

      I’ve used two different suppliers for the EM172 capsules. One was Gene at Frogloggers, who I don’t think is taking orders right now. The other is FEL Communications in the UK. The reason I mention this is that FEL sells the EM172 as a bare capsule, a metal can with holes in the front. Gene sold the EM172 with a water repellent black cloth stuck to the front. I used one of the capsules I got from Gene on that article, so the black stuff on the outer face is that water repellent cloth that came with the capsule.

      I’m pretty sure it’s a standard thing for electrets, but I haven’t found a supplier. I’d like to, though, because I’m building some new SASS arrays using capsules from FEL that don’t have that water repellent layer. These are for overnight use outdoors, so I’d prefer to have it.

      I didn’t use the rubber sleeves for that build. The first round of flush mount mic bodies I made pre-dated my really thinking about grounding for the capsules, so those are just bare capsules in a black Delrin tube with the wires soldered on the back. I made the holes in the mic bodies just under-size so the capsules had to be gently pressed into place. This caused me some issues later when I decided to change the design to add better shielding. I basically had to cut the mic bodies off with a saw.

      Some time after that design I converted everything to XLR plugs and added better shielding. I think the same shielding principles would apply to a 3.5mm plug setup. Here’s the newer article:

      https://tombenedict.wordpress.com/2016/03/05/diy-microphone-em172-capsule-and-xlr-plug/

      In that case I over-sized the hole in the mic body to leave more room for the insulation and shielding. Rather than having a press-fit, which gave me so much grief, I made it a slightly loose fit and used a little E-6000 adhesive to hold the capsule in place. It only takes a tiny amount, and it can be removed later on with an X-Acto knife if you need to take the thing apart.

      I’m still on the fence on mic bodies. A while ago I changed all my Primo mics over to the Clippy mic bodies sold by FEL Communications:

      http://micbooster.com/microphone-holders/69-clippy-mic-enclosure-and-cable.html
      http://micbooster.com/microphone-holders/96-clippy-enclosure-grommet.html
      http://micbooster.com/clippy-em172-microphones/67-spare-clip-for-clippy-microphones.html

      I have mixed feelings about the Clippy mic body. It’s a nice setup, but I think it recesses the capsules too much. I left off the thread-on mesh face and used the same E-6000 trick to flush-mount my EM-172 capsules. This ruins some of the appearance of the mic, but since they live most of their lives inside wind protection, I never really see it.

      As for the specs on the flush mount body I wrote about in the article, I could probably find my drawing for it if you like, but I’m not sure I’d make it again, myself. One reason I kept going back to that design (outside diameter, length, depth of that slot, how far back the slot is, etc.) is that I’d designed my first SASS to have tubes that size, a set screw in that particular location, etc. Each time I re-built my mics, I had to keep using those same dimensions so the things would fit in my SASS. As a general purpose mic it’s not that friendly. I only found one clip that fit it, and it’s a little too large to use as a general purpose lavalier mic. In that regard the Clippy bodies really are a better design.

      Sorry for being so vague. I hope this helps.

      Tom

  2. mikejames852650772 said

    Thanks a lot for this Tom, it’s very helpful. I agree about the clippy mic casing – I have one and the mic is indeed quite far recessed. From measurements in our anechoic chamber here in Edinburgh I believe that this accentuates the boost around 10kHz quite significantly.

    Many thanks again,
    Mike

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