Correct me if I'm wrong:

But isn't line-level = line-level???

I could have an CD diskman go into a old car tape deck (with the aux jack in the front) into a home amp; it doesn't change the fact that it's line-level?

And thus:

http://www.mobileaudio.com/rac-faq/rac-faq_5.html#SEC106

That applies to any line-level signal...

...correct?

I don't understand your question, but there are variations in output level of devices that you would call line level. For example look at headunit specs, some reach up to 8v and others 2v.

I don't understand your question, but there are variations in output level of devices that you would call line level. For example look at headunit specs, some reach up to 8v and others 2v.

Forget voltages for now...

...what I mean is that they are all line level signals; and, if you wanted to combine them into a mono signal, you have to use a summing circuit.

Right???

A line level could be mono. Generically speaking line level describes the strength of an audio or electrical signal that is transmitted down a wire.

A line level could be mono. Generically speaking line level describes the strength of an audio or electrical signal that is transmitted down a wire.

I'm talking about left-n-right rca's being combine to a mono signal...

...and how you need to use a summing circuit.

Some people think you can use a "Y" cable (which is wrong)...

I'm talking about left-n-right rca's being combine to a mono signal...

...and how you need to use a summing circuit.

Some people think you can use a "Y" cable (which is wrong)...

Correct.

You can split, but not sum.

I'm talking about left-n-right rca's being combine to a mono signal...

...and how you need to use a summing circuit.

Some people think you can use a "Y" cable (which is wrong)...

Correct.

You can split, but not sum.

I know...

...I just need the correct ammo to instruct others.

wtf does the topic "line level..." have to do with a summing circuit.

You need to stop using frigging dots and ask an actual question.