2014 JBL Entune HU Replaced... Caller Volume issues, Preout Amp?

TBH, even with the stock HU, the caller volume wasn't as loud as I would have like it, but now I have installed an Alpine iLX-F309 and it's even lower. The F309 volume is 0-30, at 0-14 with road noise is like it's barely there, 14-30 I can hear fine. Problem is, the volume for phone calls is 0-11. Sitting still I can hear a caller ok, at max 11, as soon as I'm going down the highway, nope. the only sound outputs that go into a JBL tundra are LF and RF, from pre-outs from an aftermaket HU. IF I put one of These in between, could that fix my issue? OR will this cause problems?

 

is the alpine headhunt sending a signal to the jbl amp or straight to speakers?

 

It’s sending it to the JBL Amp.

 

Anyone? I’m going to attempt this tomorrow, but if you think it may break something please chime in.