Paul,
Thanks for the reply. That's what I had assumed, which is why I wondered at the change.
Actually, now that you ask that, I realized I do have a current release MTH AC4400CW and it too sounds more tinny and less full and bass-filled compared to earlier PS3 engines. I don't have an earlier AC4400CW to compare it to, though.
As specific comparisons, I have an Atlas BNSF SD70ACe and an MTH BNSF SD70ACe from 2014, as well as an Atlas NS SD70ACe and an MTH NS SD70ACe from 2018, and finally an Atlas P42DC and an MTH P42DC from 2013. In each case, there's a marked difference in bass and distortion at higher volumes between the two, with the older PS3 engines winning out.
I realize sound quality is impacted by the sound file, board drivers, speakers, sound enclosure, and more. It does seem like something must have changed in the production on MTH's end lately. I should add that the Atlas models sound ok on their own - it's not like they're terrible by any means, but are noticeably different when compared to the older models.
