Unreasonable

I'm quite confident I don't have any level adjustment on it. Would something like this work? I should mention I'm already using RCA connectors for the connection between the units. Amazon.com: Harrison Labs 12 dB RCA Line Level Attenuator Pair: Electronics: Reviews, Prices & more

I have a line level aux source (OmniFi MP3 player). With the aux in on the Leptronix, the result is a signal level which is way too big. Any ideas?

Any chance one of these might be made to work with a USDM Outback (Head Unit P-201UN) ?