Speaker amplifier for Samsung Note 4 with case

After having a phone with front facing speakers, I really found it annoying that to get decent sound from my Samsung Galaxy Note 4, I had to cup my hand around to the back. There's a few 'docks' with a similar concept for iPhones and such, so I mocked up a quick model for the Note 4.

Please keep in mind that I made this for a Note 4 which had a Verus Iron Shield case on it. It's not a tight fit but it's at a stage that's good enough for me without having to remove the case.

Can't say what