Converting DCC to sound

[uncbob]

Converting DCC to sound
I have 3 Bachman steamers with DCC and Sound ( 2-8-0  4-8-2  2-6-6-2 )and am satisfied with how they perform IN DC mode

I have 2 DCC only ( 2-8-4 and 4-8-4 )

Are there any instructions  on converting to sound --what decorders  are needed and what speakers --installation instructions etc

I want to  operate only in DC mode like my others

[uncbob]

Why can't I just set them up like my other sound powered Bachmanns that run in DC with Bachmann decorders or
does Bachmann use Tsunamis that are preset for DC/DCC ( CV 29 to 6 )

Thanks for the link