Spkr level inputs vs. RCA
I'm setting up a small bedroom system and I plan on using an old reciever I have. It has no sub specific output so I'm looking at just using the speaker level input. How much of a difference in sound quality does this make? The guys at the store say it shouldn't be noticeable, but I want some real world answers.
You either want to rethink or reword your query.
If you are talking about using the speaker outputs on your receiver to drive the speaker level inputs on a sub, then you're fine. That's what they are made for.
If you're talkng about using speaker outputs to drive a device with line level RCA inputs, you may want to rethink that big time. I'd advise against it.
In your particuar situation I would avoid any sub without speaker level inputs.