A few here might be interested in this document. At least many here will know what is involved and not only for HO scale is why I put this link here. You can download the document to your PC.
http://qsisolutions.com/pdf/loco_acoustics_design.pdf
Rich
Rich,
Thank you for posting this! I have a part time job as an Audio Tech and this stuff is great. I have saved it so I can read the whole thing at a later date. Sound systems for locomotives have come a long way but I feel they have a long way yet to go.
Thanks again,
Brad
Very useful, thanks for sharing!