Long distance Audio Communication

[vishweshgm]

Hello,

I am very new to audio processing & I want to understand how does the audio communication work in high rise buildings?

Let's say I want to build a system which puts a microphone and a speaker in each floor of a 100-floor high rise buiding, and one central microphone, speaker at a control room. Residents can either listen or transmit audio to&from control room. How do I design the system?

Analog, digital? Resolution? Dynamics, quality, expected delay between receivers?

Here are my thoughts. Please suggest/correct me wherever you feel necessary:

1. I want to have a Wired network instead of wireless. Because radio signals might not reach every floor from control room (which I assume situated in basement). Also I want to have the delay between transmitter and reciver to be very small as in 10s of milliseconds.

2. I want to have an Analog transmitter/Processing circuit instead of digital. Because transmitting digital code over long distance is not reliable. Also I want to have better voice quality than just some 8kHz sampled signal.

I want to understand if such system is practically possible, if yes, please suggest some circuits/challenges that I should prepare?

 

[KlausST]

Hi,

Analog, digital? Resolution? Dynamics, quality, expected delay between receivers?

Analog as well as digital will work. You know analog telephones worked for decades over 1000s of km.
But nowadays I´d rather go with digital systems.
***

Resolution, quality and so on:
Usually we can´t answer this. It´s determined by the application´s requirements.
If it´s just for fun "communication", then I guess you are free to use what you want. If tis is a part of an emergency system, then you have to keep on standards. Some standards even require tht the whole system is periodically tested (every couple of minutes) .. from microphone to speaker.
So: It depends.

Even for audio in a supermarket I recommend some quality ... not to annoy the customers (and personel) with high distortion or noise.

***
1) I´d also rather use wired than wireless. Maybe more a taste. But maybe consider to use fiber optic.

2)

Because transmitting digital code over long distance is not reliable.

I agree. This is why internet, digital telphony and cell phones never will become popular ;-)

Also I want to have better voice quality than just some 8kHz sampled signal.

Just "voice" does not need more.
If you want or need better qualtiy ... then it´s on you to to define the quality somehow.

***
So there are plenty of ready to buy solutions. Analog, digital, low to high quality, according some required standards or not.

Thus I recommend to first (maybe talk to your client) find out what you really need and what is "nice to have". Best if you can define it with standards, numbers with values...

Then do a research about the available systems, just to get a clue how others do it, and the benefits and drawbacks.
.. To find out which way you want to go.... and to ask more detailed questions.

****
I disagree with some of your opinions. Thus - if I had to design the same - to sell it multiple times. I guess I´d go with ethernet. This means you most probably can use already installed ethernet. It is simple to install (no need for an expert) and expand. You may use PoE, to avoid extra power supply at each node. And the cost and reliabilty should be fairly good. But in detail it depends on your requirements..

Klaus