Model as received:
Equipped with a LokSound 5 decoder and DCCSound's Premium speakers:
First, the factory speakers are removed along with the DC dummy plug. Then an ESU LokSound 21-MTC V5 decoder with GM12 sounds is plugged in. DCCSound twin-sugarcube speakers featuring the larger 13x18mm drivers are installed, being a very simple snap-in fit to the chassis. The body shell is refitted. All done!
Below is a similar installation, this time in a Trainorama S class model. The 21 pin version's motor connections seem to have been wired opposite to one another, such that the value of CV29 needs to change.
Trainorama 42 class with "Limited Edition" speakers: