I purchased a used MTH C&O 2-6-6-6 Allegheny a while back that I wanted to do some upgrades on sound wise. This one is the first PS2 version cataloged as 20-3115-1 from around 2003. It runs great, but needed a little work. It's missing some of the brass catwalk covers with the tread and the magnet on the speaker was beginning to disintegrate. Cleaning out a bunch of the metal/magnet shards improved the sound a bit, but it was still lacking.
I had previously used Mark DiVecchio's ADPCM tool to edit some sound files so I thought pairing that up with a new speaker could really turn this tired H-8 into a show horse.
I started by selecting a few speakers from Mouser to try out, and these were the candidates...
Visaton FR 58 https://www.mouser.com/ProductDetail/243-FR58-4OHM/
Visaton FRWS 5 https://www.mouser.com/ProductDetail/243-FRWS5-4OHM/
DB Unlimited SP530104-1 https://www.mouser.com/ProductDetail/497-SP530104-1/
DB Unlimited SP500208-1 https://www.mouser.com/ProductDetail/497-SP500208-1/
After trying them out, based on my initial testing, and taking into consideration how easy it would be to retrofit them into the existing chassis, I ended up going with the Visaton FRWS 5. It was also the most expensive of the four at $10, but is definitely the most well made of the smaller two speakers. It also has the benefit of a built in "seal" that didn't require any sort of baffle to be made.
I also took some of the sounds from the PS3 version of the Allegheny and modified them for use in a PS2 board. Mark has instructions for how to do this on his website. The sound quality isn't really affected all that much surprisingly. I think the key with the compressed PS2 sounds is that the recording has to be of fairly good quality to start with and benefits from careful modifications to EQ, dynamic range, and sampling rate.
I replaced the chuff sounds, whistle and alternate endings and added the grade crossing signal. I made room by deleting some of the train wreck sounds and other accent sounds I wasn't very interested in. I also put some added touches on the grade crossing sound in Audacity by adding some reverb and EQ to make it sound more distant and ghostly. I was looking for a sound there that would more accurately reproduce the live sound of the hooter bouncing off the walls of the Blue Mountains through which the C&O was famous for hauling coal.
Anyway, enough talking... here's the finished product.