Ex our post production facilities - a "fun mic" for recording experimentation particularly "overall sound reinforcement" capturing the whole-of-room sound, not as a specific instrument mic
This microphone is from the Radio Shack/Tandy stable, with their own branding OPTIMUS - not 100% but it is most likely an OEM product from Sony Japan or "perhaps" a Sennheiser OEM product but I think the former is more likely.
Radio Shack/Tandy did not make any of their products but did use interesting sources and those who like to experiment with old microphones or what are generally considered non-professional have found interesting and surprising results from the Radio Shack/Tandy range of days gone by - it all depends upon the purpose of the mic and the sound you want to achieve and most often at the lowest cost possible.
OPTIMUS STEREO MICROPHONE
Model: 33-9956
1980 - 90's release (not too sure, we got this mic in the 1990's but it had been on the market for a while before that I seem to remember)
Comes with the original foam pop filter/windshield, output lead and 3.5/6.5 adapter
Technical Specifications:
Element type: twin electret or "back-condensor"
Requires a local power source, standard AA battery (1.5V)
Not to be confused with the more commonly (and expensive) "normal disc condenser" microphones which require a phantom power source, although I have seen some die-hards convert these to run with phantom power, this microphone has not been modified in any way.
If you aren't familiar with the two types of condenser microphone technology, have a look at this link:
To quote from the webpage:
"A good back-electret mic can perform every bit as well as a traditional capacitor design, and in some cases a little better, though the electrical charge sealed in the electret material can leak away very slowly over a period of several decades, resulting in a slight decrease in sensitivity. In reality, though, this leakage is generally so small as not to be a practical issue."
Switchable On - Off
Expected characteristics (I have hunted "high and low" but I cannot locate a reliable technical source for this particular microphone)
Typical frequency response: 80 - 15Khz (nothing startling, especially at the low end but very flat)
Presumed to be around 600 Ohm impedance
Sensitivity: High (electret style microphones can be a bit touchy, picking EVERY sound around them)
Barrel switch: ON-OFF
Strong aluminium body (black), lightweight
Audio capture areas are each side and the top - it would have been nice to have a polar characteristics diagram but I don't.
Output is via a 3.5mm stereo socket - screw down fixing. Nice secure attachment of the 3.5mm plug to the microphone, it will not fall out if being hand-held!
The output lead is short (50cm) and the non-microphone end is a 3.5mm stereo plug, but an adaptor is also supplied for 6.5mm use.
Microphone weight is approximately 100g WITH THE BATTERY FITTED
COSMETIC CONDITION:
Excellent. body and head are unmarked and very clean
Cable is original and undamaged. No manufacturing ID on the cable sheath.
Jack plugs are nothing special, moulded plastic - undamaged.
Battery contacts are very clean, shiny with no corrosion
TESTING:
Powers up fine - uses a standard AA size battery, Alkaline or Lithium will be fine. You must insert an AA battery otherwise this microphone will be as dead as a dodo!
The lower half of the microphone body unscrews easily, just pop in the battery noting the correct polarity
The audio quality is "average", from each side is noticeably "fuller" with far better low end response, vocals into the top sound quite "reedy"
On - Off switch is noiseless - no great "THUMP!" when operated
Not a great choice for instrument mic work as you will get a great sound from one side of the microphone but it is also going to also pickup audio from the opposite side, unless you just use one channel!
But our sound engineer liked this mic to capture that "overall room sound" or simply for basic voice actor work - nothing flash but it did the job for some situations.
Both channel outputs working fine and are of the same audio level
I am supplying the microphone exactly as in the photograph EXCEPT there will be NO battery supplied.
It is likely this will be shipped and not picked up and in my experience, the Australian Postal service is "touchy" about items with batteries inside.
The original box is long gone but we have always kept this microphone in a sealed plastic - that is how it will be supplied.
