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Audio Systems/wireless microphone technology


QUESTION: namaste,
i have main two question regarding the wireless microphone technoloty.
1 - describe in detail the following techonlog.
    diversity receiver, true diversity, pll systhesis,sml technology.
2 - i am planning to purchase akg wms40 mini dual vocal microphone so i want to ask that this microphone comes with diversity receiver,pll systhesis , sml technology and also want to ask what is the operating range distance? AT LAST i want your opinion which is the best wireless microphone in this catageory.

ANSWER: True diversity or dual antenna diversity uses two antennas placed a few inches or centimeters apart and a circuit that can select the better of the two signals being received.  They are much more powerful in avoiding drop-outs and dead spots.  The single antenna is prone to drop-outs when the person carrying the wireless mike moves around.

PLL or Phase Lock Loop circuits are using an electric feedback systems that gives it the ability to track the received signal even if the frequency wanders or changes a little because of instability of the sending circuitry to be exactly on the right frequency.  Also, when in motion the sending system may be velocity modulated and difficult to track by simple rf receiver. PLL aids in these cases.

I don't know what you mean by sml technology.  Can you explain more?

For the AKG WMS40 system, please go to this web page:

where you can download PDF documents about its technology and applications.

I do not make equipment recommendations because there are too many subjective and application specific issues involved in making the right selection.  But, I wish you the best and hope that your research will lead you to the right decision for you.

Have a wonderful day.

---------- FOLLOW-UP ----------

QUESTION: Namaste sir,
you had mention akg wireless wms40minidual web link i went there but i found there is no information regarding my queation. so i request you to give your and other people input in reply of my following question.
1 - whether akg wms40minidual come with pll systhesis technology?
2 - whether akg wms40minidual come with smt technology?
3 - whether akg wms40minidual come with diversity receiver?
4 - what is the operating range of akg wms40minidual in feet?

If you go to

you will find the mini comes in different configurations.  Either one antenna or two (diversity).

You should decide which unit you are thinking of and do accordingly.

The mini2 spec sheet (downloadable pdf on AKG pages) gives complete answers to your questions.

The WMS40 mini2 Sets ensure brilliant sound and ease of use at an unbeatable price/performance ratio.
Unique HDAP (High Definition Audio Performance) technology ensures the best possible, most realistic
sound at any time.
The SR40 mini2 receiver provides three status LEDs each for channels 1 and 2, indicating ON/OFF
status, received signal strength (RF OK), and audio clipping (AF CLIP). The VOLUME control sets the
level at the ¼" output jack. Each receiver comes with a universal 12-V switched mode power supply with
EU, UK, and US adapters. The illuminated ON/OFF button switches both channels on and off
The PT40 mini bodypack is probably the smallest and lightest transmitter in its class. A reliable mini XLR
input allows you to connect every compatible AKG miniature microphone.
The rugged HT40 mini handheld transmitter features an ON/OFF/MUTE switch and a sturdy wire-mesh
cap protecting the cardioid dynamic microphone element. Battery life is the same legendary 30 hours off
a single AA battery as for the standard WMS40 models, reducing the need to replace batteries and thus
saving real money in the long run.
AKG Acoustics GmbH Lemböckgasse 21–25, 1230 Vienna, AUSTRIA
AKG Acoustics, U.S. 8400 Balboa Boulevard, Northridge, CA 91329, U.S.A.
© 2012 HARMAN International Industries, Incorporated. All rights reserved. AKG is a trademark of AKG Acoustics GmbH,
registered in the United States and/or other countries.
Features, specifications and appearance are subject to change without notice.
» Vocal Set - 2x HT40 mini, SR40 mini2
» Instrumental Set - 2x PT40 mini, SR40 mini2
» Mix Set - 1x HT40 mini, 1x PT40 mini, SR40 mini2
Carrier frequency range 660 to 865 MHz
Modulation FM
Audio bandwidth 40 to 20,000 Hz
Frequency stability (-10°C to +50°C) ±15 kHz
T.H.D. at 1 kHz typ. 0.8%
Compander integrated
Signal/noise ratio typ. 105 dB(A)
RF output typ. Max. 10 mW
Power requirement single 1.5-V AA size battery
Battery life >30 hours


Range is a function of the environment and location settings but they are designed for use in commercial spaces.  For example, in Las Vegas nightclub shows they use them where the sound board and receiver is quite distant.  In churches, schools, etc. probably 100 meters is too far but 20 to 30 meters is good - in my personal guesstimate.

Hope this will help you.  

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Audio Design Engineer; systems, loudspeakers, cd/dvd players, etc. I am knowledgeable in all high end audio equipment and installations. MAKE SURE YOU GIVE A MAKE AND MODEL NUMBER AND CAR IF IT IS AN AUTO QUESTION. Note: I am getting some who ask good questions that take a lot of time to research but then the questioner fails to read the answer. Please don't ask questions unless you are seriously looking for an answer. If you find an answer to your question otherwise then let me know with your reply. Thank you.


Have been associated with audio design, standards, testing and component systems for over 40 years.

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