Installing a Peltor MT-63 headset/microphone in a Shoei full-face Helmet

Date: 2003

Alternatives:  I like the Peltor kit over the Avcomm because the adjustable microphone position. 
               it is critical to get the microphone within 1/4 inch of the lips.

Specs:  Peltor MT-63 Full-Face in-helmet Headset/Microphone Combo  (around $100 US)
         -TL-104 Nexus plug to connect to intercomm (standard for Rally/Offroad/Marine)
         -32 Ohm speakers, in parallel, (16 Ohm) 
           (can be wired independently and connected to TL-105 Nexus Plug for Stereo)
         -Noise-Canceling Electret Microphone with 3 position height adjustable (used here)
         -durable Wiring (very nice and durable)
         -Molded rubber jackets/wire releif for speakers
         -Can't come close to this quality with low-cost computer headset.

Pictures:

1. Mach-up the position of the speaker and microphone modules.
   • SPEAKERS:
   • put the helmet on your head and slip in the speakers
   • hold them in place and take off the helmet
   • note the position. it is usualy in "the right place" which will leave some styrofoam on the pad when you do the cutout. see pictures...
   • MICROPHONE:
   • use painters-blue-masking tape or gaffer tape to secure the position of the microphone on the inside of the chin-pad
   • it should be 1/4 inch away from the mouth when the helmet is on.
   • I chose to move it also 1/4 inch below my bottom lip, so air-noise/moisture from my nose breath would not muck-up the microphone.
   • noise-canecling electret microphones like this work by "keying up" only for close-proximity noises.
2. Try the helmet on again with the blue-tape holding the microphone/speaker in place and verify propper positioning
3. Remove lower/inner-liner by pulling away padding near ear-cavity (notice the retainer-clip thingy at the end)
4. pull the inner-liner completly out by carefully pulling away the RTV-like adhesive at the front(mouth/chin) section
5. cut out the speaker detents from the styrofoam. use some sort of xacto-like knife and also your fingernail to smooth-down the rough.
6. you don't have to cut the entire styrofoam bottom all the way to the open-cell-foam except in the very center of the speaker. the peltor speakers have 4 small holes in the center. see picture.
7. Take a digital-picture of your placement and print it out (or use mine here) to get the placement right on the other side.
8. use painters blue-tape masking tape to cover/secure the back of the speaker into the new cavity.
9. Microphone:
   • Permanant clean and flush Mounting:
   • the peltor microphone is a 3 position adjustable, and in this case we will use the first 2 heights
   • cut a hole about 1/2 inch diameter in the center of the front chin-guard in the place you positioned the microphone. Be careful not to obscure the molded-styrofoam air-passage which lets fresh-air in and directs it upwards across the inside of the visor for fog/steam. (trim the outer-ring of the peltor microphone if needed.
   • the center-post of the microphone should project through this 1/2 inch hole and mount flush to the inside of the helmet/chin guard. By then pulling out out on the microphone from the inside of the chin-guard, the second level of the microphone will extend. (the lower position is for putting the helmet on (being flush) and the second position should put the microphone 1/4 inch closer to your mouth which should be 1/4 inch from your bottom lip.
   • before securing with blue-tape, you can put some open-cell foam behind the microphone. this may help with accumulated-sand/dirt issues in the future and maybe make the microphone sound better (no echo?)
   • Simply use painters-blue masking tape to cover the back side of the microphone housing to secure it to the microphone. (Use this tape to also secure the wires which are usualy a bit long...)
10. Try on the Helmet and check final placement/comfort.
11. Route and secure wires with blue-tape or even better gaffer tape
12. dab some RTV or other adhesive to the blue-tape and/or chin area of the helmet shell
13. insert the lower/styrofoam section into the helmet-shell routing the chin-straps through
14. slide and tuck the strange clippy-things towards the back of the helmet.

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