This is a Rectify Series drop-in speaker system for all Athearn Genesis SDP45 & SD60/70 locomotives using the single 28mm speaker mounted in the weight behind the PCB. The speaker uses the factory mounting and no modifications are needed to replace the factory speaker.
Since these types of factory speaker cavities leave so little room for a decent enclosure, the second photo above provides an alternative with one of two simple modifictions. Either remove the rear weight altogether or cut-off the round speaker part, leaving the rear part of the weight and install my RAPO-40CM system. This cut is very easy to make with an inexpensive hack-saw and about 60 seconds of work. This will provide a MUCH bigger, beefier sound with greatly improved bass.
The speaker comes fully assembled and tested.