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#1
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What makes a quality mic?
What makes a quality microphone in a headset? somethat that doesn't pick
up the cockpit noise, but still transmits your voice clearly? I've got a project in mind that would require such a microphone. I thought of using the parts from a reconditioned headset, but I'd like to get some opinions/options. John |
#2
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What makes a quality microphone in a headset? somethat that doesn't pick up the cockpit noise, but still transmits your voice clearly? I've searched for the best performing mic and have found that the Sigtronics M-80 and M-81 mics to be the best at cancelling out high noise, yet not muffling your voice too much. Not surprising as this is what they were designed for... open cockpits with a screaming 2-stroke engine 5 feet away. A little steep at $90 from http://www.sportys.com/acb/showdetl....ID=5970&DID=19 Alternatively, Sigtronics makes headsets for EMS/Fire rescue. You can find a fire supply liquidator on ebay selling headsets with a 'hard wired' M-81 on a flex boom for $50. Easy to remove the boom with attached mic and mount on your existing headset. Search for 'Sigtronics SE-8' for example: http://cgi.ebay.com/Sigtronics-Noise...QQcmdZViewItem Dean A. Scott, mfa --------------------------------------- School of Visual Art and Design southern adventist university --------------------------------------- http://www.southern.edu/~dascott |
#3
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"John T" wrote in message ... What makes a quality microphone in a headset? somethat that doesn't pick up the cockpit noise, but still transmits your voice clearly? I've got a project in mind that would require such a microphone. I thought of using the parts from a reconditioned headset, but I'd like to get some opinions/options. Presuming that the question is general theory, you are primarily looking for a headset with a noise canceling mic. Classically, a noise cancellig mic is two microphones placed either back to back or a radically different distances from the mouth of the person speaking. For example, a mic pickup placed one inch from the speakers mouth, and the second at three inches, so that the evels are radically different. The two microphones are then wired out of phase, so that the background noise, which is assumed to reach both microphones equally, will be cancelled. In addition, sound outside the classic "telephone" band of 300Hz to 2500Hz can be filtered out for a further benefit in intelligibility. The low-tech solution above works amazingly well in a large open area, especially outdoors, and also works well with a noise cancelling hand held mike when held closely; but has serious limitations in an aircraft cockpit, especially if the mic boom is not long enough to provide good proximity. I understand that some of the newer earpeices include a microphone to pick up a pilots voice, presumably by bone conduction, and include sufficient filtering to restore a reasomable range of frequencies. In addition, some of the newer microprocessor based filters may provide far better noise cancelling than the older methods. However, I have been out of the avionics industry for nearly twenty years, and have no experience with either of the last two methods. I hope this helps. Peter |
#4
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John T wrote:
What makes a quality microphone in a headset? somethat that doesn't pick up the cockpit noise, but still transmits your voice clearly? I've got a project in mind that would require such a microphone. I thought of using the parts from a reconditioned headset, but I'd like to get some opinions/options. John Electret noise cancelling mic. Matt |
#5
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This is a bu11$#it answer below.
In aircraft use, the microphone is open on both sides in the holder. Noise coming in one side is cancelled by noise coming in the other side (i.e. they both hit the microphone in phase and push and pull the element equally, cancelling out the noise response). How much they cancel is a function of how well the mic holder is engineered and tested. Your voice hits the mic on one side only, and is thus imbalanced. It is this imbalanced output that you get to use for mic audio. Again, the ONLY thing that cancels noise is how well the mechanical/acoustic engineer designed the mic housing to cancel the noise. Jim Classically, a noise cancellig mic is two microphones placed either back to back or a radically different distances from the mouth of the person speaking. For example, a mic pickup placed one inch from the speakers mouth, and the second at three inches, so that the evels are radically different. The two microphones are then wired out of phase, so that the background noise, which is assumed to reach both microphones equally, will be cancelled. In addition, sound outside the classic "telephone" band of 300Hz to 2500Hz can be filtered out for a further benefit in intelligibility. |
#6
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Maybe I should clarify what the project is. I have a cochlear implant
(do a google search....some of you at the Oshkosh RAP party may have noticed a "wire sticking out of my head" (not really...just from the magnetic headpiece)). To hear the radio, I just make a direct connection from the planes headset jack to my belt worn, external processor. I have a setting that is 100% input from this auxilary jack, thus only the radio comes through. Now, what I want, is basically a headset with a boom mike, much like those lightweight, wire-like headsets being offered these days for mucho bucks, but with only the boom mike. I contacted a couple of these manufacturers, one was willing to try, but he misunderstood that I didn't need the audio jack and volume control, and qouted me for that. I asked for a corrected qoute, but never heard back from him. Anyway, I'm thinking of designing a boom mike only headset. That is my project. First thing is to find the microphone, then design a thin arm, elbow (or whatever you call the part where the boom meets the headset), and headband. Not only would this save room in my flight back, but look really, really cool! I have also thought of buying a computer headset, but I don't think their mikes are geared for a high noise enviorment. John |
#7
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I'm thinking of designing a boom mike only headset.
Then follow what I said in my first reply... "... You can find a fire supply liquidator on ebay selling headsets with a [permenantly mounted] M-81 [high noise cancelling electret mic] on a flex boom for $50 [not an articulated wire boom, this is a single flexible "gooseneck" tube-type boom]..." http://cgi.ebay.com/Sigtronics-Noise...QQcmdZViewItem In other words, get this cheapo headset (actually only one earcup is noise reducing, the other is slotted to let in outside sound, the boom is mounted on the closed cup), remove the boom by unscrewing a single nut inside the earcup, discard everything else, mount the boom to your own headset's ear cup (3/8" hole I beleive), and connect the two mic wires to a cable with a suitable plug for your radio's mic input jack. Or, contact Sigtronics Parts and order a replacement boom mic assembly for their SE-8 headset, but I guarantee it will be more than $50! Dean A. Scott, mfa --------------------------------------- School of Visual Art and Design southern adventist university --------------------------------------- http://www.southern.edu/~dascott |
#8
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What about throat mikes?
Someone may be able to suggest a source for one? Peter "John T" wrote in message ... What makes a quality microphone in a headset? somethat that doesn't pick up the cockpit noise, but still transmits your voice clearly? I've got a project in mind that would require such a microphone. I thought of using the parts from a reconditioned headset, but I'd like to get some opinions/options. John |
#9
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Thanks Dean,
I did a search on your earlier suggestion for the sigtronics SE-8, and didn't get any hits. That headset looks like something to use. John |
#10
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but there aren't any on Ebay at the moment. There's ALWAYS an SE-8xxxx on ebay being offered 'Buy It Now' from Fire Equipment Liquidators http://stores.ebay.com/id=37098259&ssPageName=VI:SIB:StoreView. Currently it's item number 7717678330. This guy/company sells one at a time, but apparently has dozens in stock since he's been listing this headset for at least the last 6 months. FYI, this is what did. I was increasingly displeased with a Flightcom A9 mic... just not good at open cockpit/engine noise reduction. A friend had an SE-8 that sounded exceptionally clear and engine noise free over the radio. I was envious and went looking for a way to get one of those M-80 mics. Found this ebay seller and got his SE-8SRPTT headset. The SRPTT part means Slotted earcup, Radio Push To Talk. I didn't realize that until after getting it. Wanting what my friend had, I called up Sigtronic Parts and ordered two, undrilled, closed (un-slotted) earcups ($12 ea) and a speaker (the slotted earcup obviously doesn't have one). I then went about converting/rebuilding the SE-8SRPTT into a regular SE-8 (no volume control or PTT switch on the boom mic earcup). Another thing is that the SRPTT comes with a helicopter plug (double ring). I replaced it with a standard 14/" stereo plug for the now stereo headset speakers and a 1/4" mono plug for the mic. The AVIATION version of this, the S-8, costs around $230. I rebuilt to the SAME specs for at total of $97. Dean A. Scott, mfa --------------------------------------- School of Visual Art and Design southern adventist university --------------------------------------- http://www.southern.edu/~dascott |
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