I have an HDTV which has a digital audio out function, I do not see anything about RCA output for audio.
I also have a set of 5.1 speakers which are analog with 3 jacks, I believe it is this system.
How can I hook those speakers up to the digital audio out jack on my TV? It would be cheaper than buying a soundbar.
FWIW, I don’t think I need true 5.1 sound with 3 channels because all the speakers are near the TV.
You’ll need something like this. If you can tell the TV to output stereo you can get by with a $20 converter.
what TV do you have?
LG brand 47LM6200
The speakers have a 3.5mm headphone jack, but the TV has a digital audio out function. I don’t know if that will work. I’m looking online, I don’t know what kind of converter will work for that kind of situation.
Will this do it? Anyone know?
I’m pretty positive that will do it. You’d be using the “optical SPDIF”. However, that does not come with a cable.
From what I can gather… optical audio is capable of carrying 5.1 surround sound signals… So you could probably get one that supports your speakers in surround sound… don’t they have something more than a headphone jack? If not they’re not really real surround sound. 
I have a headphone jack with my 26" TV and hook up computer speakers to it. You don’t have to have a surround sound decoder to get the some of the effect. Sounds that appear outside the area of the speaker are created by delaying the signal between speakers to fool the ear. While I’m not getting the full effect of surround sound I do get some of the spacial encoding. I find it a bit unnerving to hear sounds way to the left or right of my TV which is where the speakers are located.
You’ll definitely need some sort of active converter (a passive device is not possible). It also doesn’t work for all sound sources.
For example, I helped my dad with this same exact problem, got a little converter box to switch from the digital to analog. It works perfectly for his Blu-Ray player, and his Xbox 360, but when he tries to watch HD tv through his cable line (no cable box), the sound comes through as a very loud annoying buzzing/clicking.
So those converting devices aren’t perfect and the absolute best solution is to get a digital audio receiver/home stereo system.
http://logitech-en-emea.custhelp.com/app/answers/detail/a_id/8793/section/troubleshoot/crid/409/lt_product_id/211/tabs/1,3,2,5/cl/roeu,en
Above is the speaker owners manual.
The headphone jack on the right front speaker is output only - you plug in headphones and the speakers are muted.
The only output for sound is via the optical port according to the TV owners manual. If one of the converters mentioned above doesn’t work, you’d need a PC with an optical input on a sound card or the motherboard. Then take the outputs from the card/board to the speakers. Or get a home theater receiver with an optical input and use the analog output (you’d only get stereo output).
If you go with a soundbar, check for an optical input - if not, you’re back to square one.
The speakers have 3 plugs since it is a 5.1 system, but I am using this to get all 6 speakers working from one jack (for when I hook up my mp3 player or my PC, both of which have only 2 channel outputs and one jack).
My goal isn’t a true 5.1 system. This speaker set I have has bulky wires that would be everywhere. If I want to upgrade to a 5.1 or 7.1 system I’ll likely have to buy a system with wireless rear speakers. That is a multi-hundred dollar investment, and not something I’d do anytime soon. My main goal with this is that sometimes even when my TV is on the highest audio setting I can barely hear it. If the AC is on, people are talking in the hallway, and the show has low audio I can barely hear it. I want the X-530 speakers to amplify it.