Sound from an Apple TV plugged in an LG monitor
The answer is both Yes and No depending on the model. Let me explain.
The model you have linked to at http://www.lg.com/hk_en/monitor/lg-IPS277L is the Hong Kong model and this has a headphone socket. However, if you were buying the model from another country (let's use Australia as an example) it may not have the headphone socket: http://www.lg.com/au/it-monitors/lg-IPS277L-ips-monitor
The model you have linked to is now discontinued, but you can still access the manual downloads etc from: http://www.lg.com/hk_en/support/support-product/lg-IPS277L
If you download the manual it seems to confirm the headphone socket exists, but does not make any real mention of this anywhere. However, the same manual is used for both the LG IPS277L and the LG IPS237L (they are identical, one is basically the 24" model, the other the 27" model).
Now, if you happen to read the review on this page about the LG IPS237L, it is clear that for this particular model you can do exactly what you want to do.
I suspect that as long as you have a Headphone port you will be right.
If you want high-grade, super-clear sound, you must keep a purely digital connection, or at least use a TV with an actual line-out and balanced cabling, if you want to go analog.
Although it does sound like you maybe already own the TV, but then want to buy an Apple TV; so if that's the case the answer is very simple, yes that will work, of course assuming your TV has a headphone jack.
So in other words, I would suggest buying a different TV; make sure you buy a TV with some type of digital out. In this sense I think '@norcal Johny' is right-on here, with his answer above. Surely though if you haven't just already tried this out, you are planning a future purchase or a gift.
If you use the setup that you asked about, your audio is likely to get degraded in at least the following steps:
- Internet compression (if applicable) & wireless degredation
- Poor re-amping from the [likely cheap] headphone-amplifier inside the TV
- Noize from using unbalanced RCA cables
- Noize related-to that fact that your plugging a hot signal into a line-input, likely, on your amp.
DISCLAIMER: Your idea, may actually be the most common way people get audio out of an Apple TV. It is not suitable for so-called "audiophile" listening though, for sure, in my opinion even not for the average cinema fan, if you're really into nice, rich sound. As well, in my observations, the sound from Apple TV in general is somehow distorted at least slightly, to begin with, perhaps due to the wireless transmission.
Knowing your audio cables is important. There are so many variations that I will limit it to what is normal for your situation.
Most personal and home electronic/audio devices well use or have a variation of the following.
- Headphone jacks (1/8" or 1/4")
- RCA jacks
- Digital Audio Cable
Headphone and RCA jacks are the most commonly used methods and will most likely be your best solution. (If you had a hi-end sound system, my recommendation would have been different. [ Digital Audio ])
Most home stereos provide RCA and Digital audio inputs.
So in your situation the best method is to go with 1/8" to RCA audio cables from the TV's audio out to your Receiver's Audio In.
The wires can be found at most places from Amazon to Walmart.