Speakers sound too bright.

Obviously, I'm not either given me having to ask the question.  lol  I appreicate you chimming in though!

To test a speaker use a standard battery, 1.5 to 9v and connect to your speaker.  positive to positive should move the woofers towards the listener.  Most important is for both speakers to move the same way.

Ignore the app. Make sure the amp’s positive (red) terminal is connected to the speaker’s positive terminal and the amp’s negative (black) terminal to the speaker’s negative terminal. On both speakers. If one speaker was connected backwards, the bass is out of phase and will cancel out.

If the speakers are connected correctly (see above) and they are still too bright, try replacing the positive terminal strap that connects the upper and lower positive speaker terminals with a small value resistor and connect your speaker cables to the lower set of terminals. 1 ohm, 1.5 ohm or 2 ohms will drop the level of the midrange and and high frequencies a touch, more with the higher values.  5 or 10 watt resistors are far cheaper than new speakers!  And before I get roasted for modifying the crossover, please note that Wilson, Magnepan and others offer this same option to tune the level of their high frequencies, too. Those M-L speakers are excellent, don’t give up on them!

As someone once said " shiit in shiit out " or something like that. 

Someone else mentioned esl15a as a comparison and I would highly recommend that speaker instead of what you have,  on the other hand it's a bit more expensive 😉 

Run the lumin in dsd mode that sounds warmer