[ARC5] Mil Headset noise blanker

[Jim Falls]

This loud "pop" is actually in the audio signal delivered to the phones. I think I need some sort of audio clipper. 

PS: I have padded several of my old speakers and they do sound better!

Cheers!
Jim K6FWT

> On May 19, 2014, at 9:12, Roy Morgan <k1lky68 at gmail.com> wrote:
> 
> 
>> On May 19, 2014, at 12:22 AM, JAMES FALLS <radio-tuber at att.net> wrote:
>> 
>> I have a TCS and a BC-375 ... whenever I PTT, the relay noise is like a gunshot/ pair of icepicks in my ears
> 
> Jim,
> 
> I suggest a major cabinetry project:
> 
> While I worked a NIST, they installed at least one, maybe three high vacuum pumps in a lab near my office (ion pumps?). These things crate a very loud and high pitched whine noise.  The installation involved covering the whole lab interior with sound deadening foam.  This stuff was like the more common 3-inch thick gray waffle-surfaced packing foam but was white and no doubt of special composition.
> 
> There were some scraps and odd pieces left over, which have since been used in a couple of speaker enclosures with good effect.  One is the formerly empty TS-940S speaker for the TS-940.   Collins S-line speaker cabinets are FULL of holes so don’t lend themselves as well to this treatment.  The older “black Collins” speakers, and many Hallicrafters and Hammarlund speakers do, however.  They are solid cabinets except for the totally open back. They sound  much better with stuffing, and will improve even more I think when I close off the backs completely with a thick wood panel. 
> 
> I suggest you make a nice cabinet to enclose the loud-clacking transmitters completely, with *thick* perspex (Plexiglas(r) ) close-fitting  and gasketed  front doors (better yet plate glass).  Fit a couple of fans and baffled input and output air ports at the back, line with the special foam and include some lights for ease of operation.  Once you are tuned up on the QRG, close the thing up and you’ll be happier in your earphones.  The world of commercial teletype machines had such cabinets, both locally made and commercially available.  I think they used what was called “beaver board” for lining - stuff made of wood chips and about half inch thick with small holes all over it.
> 
> (This suggestion is self-directed, too.  The GO-9 transmitter I have has monster relays and is CW only.  The “800-1” inverter for it is a classic screamer, and is best mounted outside the building with long, thick wire leads.)
> 
> An expensive alternative is the Bose sound canceling earphones($300).  Even more expensive are the phones used by pilots, but they often include a microphone (Bose: $1000).
> 
> Has anyone tried to home-assemble a sound canceling system for the radio shack?  A microphone, perhaps on the earphones, with amp feeding a graphic equalizer and then a two-input mixer to feed earphones might be a start.
> 
> From my 20 years of helicopter flying:  Get the best sound-attenuating phones (or helmet) that you can find, use earplugs, and turn the receiver volume up to compensate till you can hear what’s going on.  Considerable sound enters crew hearing parts via direct conduction through the neck, face and skull.  The helmets we had dealt with this to a certain degree, in addition to having crash trauma protection.  The helo sound levels may have been in excess of +110 DB, certainly *well* into the hearing loss intensity.  The pilots sat in the front with the intakes of the two turbine engines (up to 10,000 rpm) about 2 feet from the backs of their heads.  The fellows in the back sat directly under the transmission, which was managing up to 2,000+ horsepower.  Their job was to detect faint pings returning from submarines via the active sonar system.
> 
> Roy
> 
> Roy Morgan
> RoyMorgan at alum.mit.edu
> K1LKY Since 1958
>