I have a Logitech Z623 that I would like to hook up to a receiver in order to watch TV and instead of hearing the audio thru the tv speaker, I would like to have it come thru the logitech speakers.
I'm confused on how to exactly hook it up to the receiver. The receiver is an Onkyo HT-RC430
Not understanding why your audio isn't playing through your receiver's speakers, but you could try to connect the receiver's Zone 2 Line out to the Logitech's AUX input on the sub woofer. Not sure how well that will work, however.
Since the Logitech speakers require a line level input you will have to convert the front speaker outs to line level with an adapter such as this http/www.walmart.com/catalog/product.do?product_id=21647874&findingMethod=rr
You will need to set up the receiver as if you had no sub since it is not connected to the sub output. You will also only use the stereo mode as you only have 2 full range speakers.