This is a little project I started a few months ago. Started poking around the sound ROMs and discovered how easy it is to customize voices, sound effects, and musical instruments. I'm finally finished with it! The main goal was to improve the voices (and mute some well-known annoying ones) and improve some sound effects and the music to make everything sound less synthesized and more realistic.

The funny thing is as much as Brian Schmidt advertised the BSMT 2000 sound system to be superior to all other offerings, a lot of sound effects and instruments were still synthesized. I was surprised to find out that these were actual sound samples stored in the ROMs rather than synthesized sounds produced in real time. That was a big missed opportunity as Williams was still using fully synthesized music at the time. For example, the opening guitar riff in the C&C MF background music.

Because this is a custom ROM mod I have no idea if it will actually work in real machines. The game (or at least the sound board) may refuse to boot due to a checksum error. But I don't know if the DSP checks the sound ROMs on startup. I'm guessing it doesn't given the very fast startup time. List of changes is below including a demo video and download link.

I'm impressed -> Hey, that's good work
Here comes trouble -> I'm Chaos, he's Mayhem
You blew it -> Wait!
They got away -> Phooey!
I got a bad reputation -> Gunfights, explosions, sharks...
He's getting away! -> Grab the cat!
You have no authority -> That's not what I'm thinkin'
What Leo wants -> I owe this guy one
Leo Getz -> Gimme something to do
Ho -> Moo
Police officer! -> Will ya shut up?
Get the bad guy! -> Drill him! Get outta the way!
Loaded -> Step aside
Nice shooting -> Have a nice day
We're back in action -> Don't eat the tuna

Removed:
Ok, ok, ok
Hey Moe!

To apply the changes to your u17 (lw3u17.dat) and u21 (lw3u21.dat) sound ROMs run the program included in the zip file and apply the ppf patch files to each original ROM file respectively (load the ROMs in place of "ISO" in the program, you will need to view all file types to make them visible). The version I used is 2.08 but I don't think the sounds were updated between code revisions anyway.

http://www.mediafire.com/?1zklec46gehu5yb

Not that I know of, unless you found a way to decode the binary music data in U7 into something usable like Impulse Tracker or MIDI files.

The 27256 256k chip is what you want for both ROMs, you can get them for $4 at Pinball Medic.

http://www.pinballmedic.net/game_rom.html

This is a small project done in my own time man, don't sell these just so you can make a profit. And guys, like I said I'm not even sure this will work in an actual game so don't stock up on blanks to give to friends or whatever. Run a couple of test cases first. And it it does work I'd like to see a video!

Anyone tried this in a real game yet?

Bump. Johnnyo any luck burning the ROMs?

Sounds interesting, I'll have to get a list of what's in the ROMs to begin with. Start putting together the sound you would like replaced. Any sounds I replace cannot be longer than the originals, but I can insert shorter ones. You can burn ROMs and test this correct? Can you start by burning the my LW3 ROMS and posting a video? I really don't have a way to show this running on an actual game.

Well the only Marty quote I found is "Where?", which comes before "Back to the future!" Are there any others that are less obvious? I mean it sounds fine, would seem pointless to do all this just for one quote.

All you need is Audacity and some basic knowledge of the PCM audio format, VOX ADPCM, and ROM offsets. You will need to teach yourself to work with raw audio snippets either in PCM or VOX format. Not difficult and the method is archaic but it can sound complex at first. If you're curious check out these links:

http://support.microsoft.com/kb/89879

Please post a gameplay video if you can!

Just use "import raw" and select 8-bit signed PCM with no endianness. Most are recorded at 8kHz (phone line quality) but some use 11,050Hz or even higher. If you come across some that sound like static try VOX ADPCM. If it still sounds like crap then it's Brian Schmidt's propriety ADPCM format which has not been reverse engineered that I know of. Most bites are padded by several blank (low) samples, this makes identification easy.

Thanks for the boot confirmation! Forgot to mention that you cannot edit straight in Audacity. Because Audacity interprets every byte as a sample, bytes you did not even select will change, corrupting the ROM. You use Audacity to find your offsets and convert formats. You actually need to inject a sample block (sound byte) at the offset that Audacity specifies and be absolutely sure that the ROM size does not change. To get offsets in Audacity change the view to samples. There will be a combo box near the position indicator at the bottom of the window. And since this is simple ancient 8-bit audio, each sample is 1 byte long (not 2 like it commonly is today). So you can just say "I have 19,546 samples selected, so I have 19,546 bytes to swap out here."

I use HxD to swap out blocks. Save your sound bytes in raw 8-bit PCM headerless format, then open that file with HxD. Select and copy the entire file making note of the size in hex. Convert that to decimal using Calculator in scientific mode. If it matches the length of your selection you made in Audacity, then you're good to go. Press Ctrl+E in HxD and plug in your offset and length in bytes. Once you have selected your block then paste in the block you copied from your raw PCM file. Be sure the selection size at the bottom does not change when you do this. Then save and you should be ok.

Again the reason why editing straight in Audacity doesn't work is because every byte in the file, whether it be part of the header, a pointer to a sound, or a sample, will be changed. You are feeding in binary data and interpreting it as sound. The same limitations sound data has, such as precision and range, are applied to data in the entire ROM, thus corrupting it. The same thing happens when you open a binary file in Notepad and save it, bytes Notepad does not recognize will be replaced by square characters.

No it's more than just sound data, there is a header at the beginning and some sounds have some header/pointer data before the actual sound data.

Not much room for improvement on the musical instruments, there may be one or two things I missed, I'm not sure. I changed more than you might realize, the original synthesized instruments were close to real samples, but still off. It was just bugging me to know that although these are actual sampled instruments, it still unneeddlessly sounded synthesized.

As for the muffled sounds, unless the bass on your machine has been upgraded, I can tweak those to reduce the low frequencies. I can't increase the fidelity obviously.

The only one I see issues understanding is, "Grab the cat!" I'll end up replacing that with something better, including replacing a few more sound effects like the synthesized punch sound. Any other suggestions? Should I mute "It's a (something) community..." By Murtaugh? Unfortunately I can't replace it because it is encoded using a custom ADPCM format. Thanks for the video, I had a small hiccup with one of the songs in an emulator but it seems to play just fine on the original hardware.

"That's not what I'm thinkin'" from the bomb scene. Mainly intended for if you press start with no credits.

I really need to finally wrap this up... Look at the first post, it explains how you can apply the patches to your ROMs.

That sounds awesome, great work!

Can anyone else confirm any issues when playing the "Have a nice day" callout when draining via an outlane? Just take the glass off and trigger those a few times. The sound caused a high pitch tone to play (a bug) in Pondwater's video.