Transport microphone and speakers audio through RJ45 câbles

[Joeyb197]

I don’t know if I am at the right place, and this is quite a “newby” question.

I am working on a project with a raspberry pi and I am trying to connect 4-5 speakers/microphone duos throughout my house. Since I will need pretty long cables, I thought of making it work that way, and was wondering if that would work and if not, what could I do:

- Raspberry pi 4 8Gb -> USB hub with 5 USB port.
- Plug a usb/3.5mm converter : https://www.amazon.ca/dp/B00IRVQ0F8/ref=cm_sw_em_r_mt_dp_DRNQ1X1HQD9FS5FQQA9Y?_encoding=UTF8&psc=1
- use 3.5mm -> RJ45 converter : https://www.amazon.ca/dp/B01IXZRXAS/ref=cm_sw_em_r_mt_dp_HFMT92537RZ5FVQCNPSW?_encoding=UTF8&psc=1
- use for example ~40m of Ethernet cables
- use another RJ45/3.5mm converter
- connect microphone and speakers (I guess I’d need active speakers and microphone with their own power cord, am I right?)

Would that work? Also, would it be possible the same way but for USB mic/speakers with a RJ45/USB converter?

Thanks in advance

[Terry Bites]

You can run balanced audio from a mic amp over STP- use it like regular shielded twisted pair. You will need differential line drivers and recievers. (https://sound-au.com/project51.htm) You can also send DC power the remote end using the other pairs- 960mA per pair max.
You need a separate STP or UTP lead to power the speakers. You can't run mic and speaker in the same line without getting horrible feedback and crosstalk.

However, CAT7 cable has individualy shielded pairs so you might get away with it at low power

Connecting to speakers over a long and small CSA cable will cause horrble losses and may destabilise your amp. I could work with couple of watts but not for much more.
If you want to squeeze more power you can use "100 Volt Line Transformers" Its far from ideal either way.

Tell us more about your plan.

[Joeyb197]

Hello, first of all, thanks for the answer, it is really appreciated.

I am currently building a personal vocal assistant to replace my Google home. Hence, I need a speaker and a microphone in every room I want my assistant to be. I do not think I’ll need very powerful speakers (except maybe for one room where I’d want good quality sound). For the other room, a couple of watt will probably be enough.

I want to run everything on a raspberry pi.

About your answer, I am not sure I understand every term used, I do not really have any electrical background except for personal small projects.

I thought of using CAT6, so I’d technically need one CAT cable by speaker and one per microphone, so 10 cable for 5 rooms if I want to avoid feedback and crosstalk?

I don’t know if that would be the best, but I think that would be the most simple way to do it: I’m thinking of buying speakers can be plugged in the wall, so I’ll just have to plug every single speaker in a different outlet in every room, and I will only have to transfer signal, not power. Would that be more simple?
For the microphone, if I want a small one, like a simple collar mic with a 3.5mm connector that I’ll plug in the RPi through the Ethernet, I think it will work, right? No need for extra power if I’m right?


Thanks in advance