Right way to connect a 2nd “extension” center channel speaker?

Given that you have an extra amp, you probably can try something like this:

https://www.amazon.com/dp/B00SJ49ZJQ?psc=1&ref=ppx_yo2ov_dt_b_product_details

I use them successfully to convert my subwoofer to wireless. They work great and are totally reliable. You will need 2 extra outlets to connect the transmitter and the receiver. Good luck. 

Just get a wireless powered speaker from the likes of Audio Engine, etc. and forget the wires.  That’s all you need for a kitchen speaker. 

Should I take the wire from the AVR to the Center speaker, and splice in the longer wire to the 2nd Center speaker?

In my opinion, this is not a good idea because the center channel doesn’t have all the signal for 5.1 sound.

If the Sony STR-DE995 digital MD tape out can provide PCM Bitstream, you can connect it to a "DAC" to feed the amazon amp in the kitchen for 2 channel stereo.

If not, you can using a "Optical Audio Splitter" to connect a "Digital Sound Decoder" convert the 5.1 digital signal to analog stereo signal to provide stereo sound to the amazon amp in your kitchen.

TV optical output --> optical audio splitter --> Sony STR-DE995 and digital sound decoder --> Amazon amp --> stereo speakers.

@spenav - that's an interesting idea, but my issue wasn't how to get the signal across the distance (I have a hollow moulding I can drop the wire into), my issue was where to get the signal from in the first place.

The AVR doesn't have a 2nd zone output if it's being fed by optical. So I was trying to split off the analog output from the speaker side.

@soix - it's the same issue. I would need to somehow duplicate the input to provide signal to the wireless speaker in the first place.

@imhififan - it doesn't need to have all the sound, I need the dialogue mostly. Just watching TV shows or documentaries, and can't really hear it if I'm in the kitchen and got mixers / blenders running, or even the water faucet.

I WISH the Sony AVR had an output, but apparently if you're feeding it a digital signal, it ONLY puts it out to the speakers, not to anything additional / secondary. Weird, I know. You already have the signal decoded, why not split it off to a 2nd zone as an option? Nope, Sony says you can't.

I was trying to avoid having to buy more equipment and having even more connections to manage... LOL.

There's no way to split off the center speaker and re-amplify its sound for a 2nd speaker copy?

https://amzn.to/3rTEfZP

If you use the center in your main zone, you might want to stick to the center channel only for the kitchen output. Otherwise, if you are using a phantom center you can use both the L and R.

For example, Yamaha’s Musiccast ecosystem was designed for whole house applications like yours in mind. A wireless musiccast speaker system can bring the music to another room without having to tinker with zones, cables and passives.

I use the following in my kitchen when I am cooking up a storm! You can get very good fidelity (for a kitchen, that is).

https://shop.usa.yamaha.com/en/p/audio-home-theater/desktop-audio/musiccast-50-wireless-speaker

SoundUnited (Denon/Marantz) has equivalent devices that run through their HEOS ecosystem. Sony may have something as well with their newer product lines.

@imhififan - the optical splitter idea worked perfectly! $ 25 splitter + $ 50 for a 50' optical cable + a soundbar in the kitchen with optical input = perfectly synced "2nd Center" setup that solves the problem. Thank you!

I use a Y splitter and bi-amp a pair to Von Schweikert VR4 Jr's. Absolutely perfect performance! I have none of the noted problems dual center channels are supposed to have.