Yes, I know that I always want the freshest equipment, but what if you have a Nice new LG C9 from last year and don't want to spend \$s for a new Audio/Video Receiver on it. Is there a way to use an older Denon that is 10 years old and still get decent sounds like the AVR-2310Ci. This is a 7.1 receiver, so not bad except that it has none of the modern decoding goodies.

At first I thought there really wasn't a choice, but to buy a new AVR like the Denon AVR-3700h (9 channel sound) for a small bedroom setup. But then I realized there is a way to make it sort of decent with a few hacks. So if you have an older AVR (one without eARC, let alone ARC and with only HD switching) and don't need the very latest processing, here is what you can do:

1. Modern TVs have so many sources built in already, for instance the 2019 LG C9 has Apple TV, Netflix, Amazon Prime Video all loaded into it and it supports 4K inputs as well. So the main trick is to not route everything though AVR, instead, feed the inputs, like say a computer or a game console directly into the TV.
2. Now the TV is really the video center and the trick is to get audio out of I, in effect, you are only using the AVR for the audio portion. There a couple of undocumented tricks here. The first is that if the receiver supports ARC (this means Audio Return channel and is a 1Mbps audio output *from* the television, so it is designed to carry audio back from the television to the AVR and the video then goes in the opposite direction). There is an even more advanced standard just coming out call eARC that's part of the new HDMI 2.1which passes a lot more audio signals for modern multichannel formats.
3. However, if your AVR doesn't have ARC but does optical then you are in luck. You can get an audio cable and get compressed 5.1 out of it. This is nothing like the 5.1.4 that you can get from a modern AVR, but it is pretty decent for a small room.
4. The big trick here is that the LG optical passes what is called PCM when LG Sync is set. This really had me fooled. It's a mode where you are outputting from the television speakers and optical so it falls back to PCM. It's buried in the menus in Settings/All Settings/Sound/Optical and then you need to set LG Sound Sync which only works with specific devices and if you flip it off, then you get a new setting called Auto for the parameter above. Now you get multichannel sound at least the 5.1 level.
5. The second trick is to turn of the SimpLink (which is generically known as CEC), this is supposed to control the receiver from the television. This at least for the Denon had the effect of turning this thing off randomly.