Dallee #911 Shay sound board

[trainstrainstrains]

I've just bought a Dallee #911 Shay sound board and realise I need a speaker and perhaps a battery also. Can I use any 8 hom 1 or 2 watt speaker of the appropriate size or is it best to buy a speaker from Dallee or Phoenix?  I intend to use this particular loco exclusively indoors.
About the battery, is it absolutely necessary?  I suppose it must be bought from Dalle?

Thanks in advance.

[Ted Yarbrough]

You may use any speaker that is rated 8ohm. Largest that will fit inside loco is best.