So now I'm confused, is it this,
The small speaker is fitted on all models. The sound version also has the accurathrash large speaker fitted which you can also add after the fact.
OR is it this.
For the first time in an Accurascale or IRM locomotive, the Hunslet makes use of an ESU-designed speaker. We've used this speaker due to space restrictions and this twin speaker is included in all DC/DCC ready locomotives, as well as DCC sound fitted variants. So, if you want to upgrade to sound later, you just pop the roof off, plug in your sound decoder and off you go
I'm looking to upgrade to sound as well, maybe someone can clarify what is needed. Sorry for the state of this reply , don't know how to turn bold writing off, this is what your dealing with lads,