I do have the Mpow Ground Loop Noise Isolator for Car Audio / Home Stereo System with 3.5mm Audio Cable installed with it (Amazon recommended it as purchase WITH the Soundbox unit), but it makes NO DIFFERENCE regarding the horrid ECHO.If the seller has any recommendations, and/or wishes to replace the unit, I'd be happy to give it a try, and revise my review, but barring that - I DO NOT RECOMMEND THIS UNIT!

1 for my girlfriend to replace her cheap mpow plug-in and one for the boat!

So much better than pairing times for other bluetooth adapters I've tried.5) great sound, although I paired with an Mpow engine noise filter

I also ordered the Mpow Ground Loop Noise Isolator for Car Audio / Home Stereo System with 3.5mm Audio Cable (Black) to enhance sound quality

Mpow Ground Loop Noise Isolator for Car Audio / Home Stereo System with 3.5mm Audio

Only reason for 3 vs 4 is there is some electrical noise which I solved with "Mpow Ground Loop Noise Isolator for Car Audio / Home Stereo System with 3.5mm Audio Cable (Black

With the addition of a Mpow Ground Loop Noise Isolator for Car Audio / Home Stereo System with 3.5mm Audio Cable (Black), this Bluetooth kit works perfectly

I needed to purchase the Mpow Ground Loop Noise Isolator to eliminate that sound.

Mpow Ground Loop Noise Isolator for Car Audio to go with it

you must get Mpow Ground Loop Noise Isolator for Car Audio / Home Stereo System with 3.5mm Audio Cable (Black) to clear the Ground loop noise

Bought the Mpow Ground Loop Noise Isolator for around $8 and that made the humming noise completely disappear.

I purchased this in addition to the Mpow Ground Loop Noise Isolator and the previous

I also wish the adhesive was a little better, but some good 3M tape fixed that

Then it comes with sticky 3M on the back or 2 metal clips to install anywhere in your car since it's so small and magnetic on the back another BIG BOOM!!!