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All remote microphones sends digital samples over the ether. Why no analog remote microphones?

I know that digital signals are less sensitive to noises, but there are several advantages of analog counterpart.

  • Simpler (only an AM/FM modulator/demodulator required)
  • Cheaper (no high performance AD/DA required) (Most mixers are analogue so DA is required too)
  • Lower latency (this is not significant)

Do I miss something?

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  • \$\begingroup\$ All remote microphones sends digital samples over the ether. The cheap ones from ebay (for example: ebay.com/itm/… ) do not, they use FM modulation. \$\endgroup\$ – Bimpelrekkie Feb 18 '19 at 8:25
  • \$\begingroup\$ @Bimpelrekkie the cheap ones from Sennheiser do, too. In fact, of all the halls that I ever held SDR-affine talks in, all but one had analog microphones! (Ask my audiences how I know.) Digital Mics are the future, but they are slow to come because latency is such a problem. \$\endgroup\$ – Marcus Müller Feb 18 '19 at 8:30
  • \$\begingroup\$ Latency has been a problem in music long before the era of microphones. One solution has been to have a conductor who leads the performace timing visually. Actually the whole orchestra would be unecessary if there's a conductor and someone could persuade the audience read the music from a partitude while they watch how it would be played if there were a perfect orchestra. \$\endgroup\$ – user287001 Feb 18 '19 at 9:00
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All remote microphones sends digital samples over the ether.

That's plain wrong. Most wireless microphones you'll find these days are still analog, so nothing to answer here; aside from you totally getting the three points wrong, too:

Simpler (only an AM/FM modulator/demodulator required)

Good analog reception/transmission needs good conditions; it's, today, probably harder to build a really good FM microphone than it would be to digitally transmit.

Cheaper (no high performance AD/DA required) (Most mixers are analogue so DA is required too)

A DAC is not required, that's not how LOs are generated.

Hell, you'll find that even the cheapest walkie-talkie handsets are based on digital chips (which sample a bad-quality audio FM, but that's a different story).

If analog transmission was so much cheaper, your Sennheiser mic's transmitter probably wouldn't be significantly more expensive than your smart phone's RF stage.

Lower latency (this is not significant)

Latency is the main reason why most concert-grade microphones are analogue, not digital. While digital wireless communications allows you to be flexible, spectrum-efficient and robust while still being cheap, you need to (and can!) do things like channel coding, but that always introduces latency, which is the killer in stage audio.

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Do I miss something?

Actually with respect to the electronics, a digital wireless microphone system is much more complex than an analog one! In this case my measure for complexity is the number of components (resistors, capacitors and mainly transistors) needed to build that system.

However the electronics needed for a digital wireless microphone system can be integrated into a chip (IC, integrated circuit) much more easily. Once such a chip is designed it can be produced at low to very low cost. The fact that you can now buy a bluetooth wireless headset for a couple of US$ proves this. I'm not saying such a headset has a similar quality as a dedicated wireless microphone, but the way how they work is very similar.

Also a digital system can be made to be much less sensitive to external disturbances so the audio quality can be much better as long as reception is of sufficient quality.

So your listed "advantages" aren't real advantages. A digital wireless microphone system has even more complex circuits however they can be made in a much cheaper way than their analog counterparts. For example, "high performance" ADC/DAC for audio are "trivial" to make and also cheap and as such they're used almost everywhere. A smartphone will have a couple of them already included on some of its chips.

Latency is an issue with digital wireless microphone systems as Marcus explains in his answer. This might be solved some day in the future by using higher RF frequencies and faster digital processing.

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  • \$\begingroup\$ I'm going to go with an "akshually, …" about the faster signal processing: while we could simply "explode" the bandwidth of the digital signal to make it robust against narrowband interference should we end up having that amount of spectrum, Shannon is pretty ruthless when it comes to ruining low-latency transmission with low error rates: You got noise, you will need a "sufficiently complex" channel coder that "smears" information over a long period – meaning latency. \$\endgroup\$ – Marcus Müller Feb 18 '19 at 8:46
  • \$\begingroup\$ By the way, awesome answer, +1. \$\endgroup\$ – Marcus Müller Feb 18 '19 at 8:48

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