First of all, I’m going to be talking primarily about the PC version and later ports. This is because the Gamecube version’s sound format hasn’t been reverse engineered yet to allow direct sound quality comparions (although we can make some rough estimations). If you want to read about sound downgrades in the Gamecube version, skip forward to the part where I talk about sound bugs and missing sounds.
There are several types of sound issues in SADX, and they are specific to different ports. Here’s a list of issues and the ports affected by them:
- The music no longer loops – 2004 PC port
- Lower quality voice clips – 2004 PC port (all clips), Steam and nextgen console ports (only some clips)
- Lag/stutter caused by the voice file format – 2004 PC port
- Lower quality sound effects – 2004 PC port, Steam and nextgen console ports
- Missing processing effects on some sounds – all ports
- Sounds being cut off, looping incorrectly or playing too early/too late – all ports
- Some sounds are missing – all ports
- Wrong soundbanks are loaded, causing wrong sounds to play – all ports
- Sound volume problems: some or all sounds are too quiet (PC 2004 port) or too loud (Steam/nextgen console ports)
- Sound playback problems (sounds/voice clips playing in lower quality than the actual sound/voice files) – Steam and nextgen console ports
Let’s talk about the music first. The Gamecube, Steam and nextgen console ports use ADX music files that are the same as in the Dreamcast version. On the Dreamcast, some music tracks were downsampled in the versions of SA1 that contained both English and Japanese audio clips – this downsampling was undone for the GameCube version, so unless you own the Japanese version of SA1 this is technically an upgrade (however, the Steam and nextgen console ports fail to take advantage of it and end up sounding worse, which I will discuss later).
For the 2004 PC port, ADX music files were converted into WMA files. The main problem with the WMA format is lack of looping, which means the music in the PC port fades out and restarts at some point, while in other versions of the game it loops seamlessly. This isn’t a major issue, especially because the Mod Loader has brought back ADX music support.
However, there are other problems with the WMA format. Character voice clips were also converted into WMA for the 2004 PC port. This would’ve been fine because the voice clips don’t need loop points, but the conversion reduced the quality of the resulting voice clips. Here’s a voice clip from both versions with audible quality difference despite the WMA one using a higher sampling rate and stereo sound:
A well-known problem with the 2004 PC port is the stutter that happens during the kart race when you hit the jump panels and Sonic says “woohoo!”. When this happens, the game pauses for a brief moment. This has something to do with the voice clips being in the WMA format because it doesn’t happen in the ports that use ADX audio. Thanks to the Mod Loader you can fix the problem in the 2004 PC port by installing a mod that replaces all WMA voice clips with ADX voice clips.
Although the Steam/Dreamcast Collection port goes back to ADX voice clips, which are the same as on the Dreamcast/Gamecube for the most part, there are several voice clips that were edited. Those edited clips are lower quality than the original voice clips. There are only 9 English voice clips and 11 Japanese voice clips that are different from the Dreamcast version. Most of the edited voice clips have to do with the options menu, where the “Options” part was cut out for some reason. You can hear that the edited voice clip sounds a bit muffled:
Now let’s talk about reduced sound quality. The easiest way to illustrate the reduction of sound quality is to compare jump and ring loss sounds across different versions. Here’s the jump sound:
And here’s the ring loss sound:
I think the sounds speak for themselves, but by sound quality I mean not only technical things such as sampling rate, but also volume, processing effects and looping of various sounds. The biggest problem with SADX sounds is that they are too quiet. In the Dreamcast version, almost every Action Stage and Adventure Field has some kind of a background noise that is loud enough to be audible without washing out the music. Those sounds are still present in SADX, but they are so quiet a lot of people think they are missing. One of the most illustrative examples is the machinery noise in Final Egg Act 1, which you are supposed to hear right from the start, but it’s barely audible in SADX. The sea in Station Square hotel is also barely audible in SADX. Another example is the ticking sound of the clock in Speed Highway Act 3, which is there but due to a combination of low volume and SADX’s positional audio weirdness it’s rarely heard ingame.
Some sounds have missing digital processing effects. For example, if you watch the cutscene before the Chaos 0 fight, you can hear the sound of bullets falling on the ground after the police shoot Chaos. In the Dreamcast version, that sound had a reverb effect that created the impression of multiple bullets falling, but in SADX it sounds like a single bullet. A similar problem happens with Zero’s chest thumping sound, which is barely audible in SADX because of the missing reverb effect.
There are several sound bugs in the ports that cause sounds to play too early or too late, or not play at all. The game’s sound engine doesn’t always work well with the increased framerate of the port, which causes some sounds to get cut off or loop incorrectly. A good example of that is the looping background engine noise of the Egg Hornet, which plays fine at 30 FPS, but cuts off at 60 FPS.
As for the sounds that play too early, most of the cutscenes involving the Tornado crashing or landing have sound timing problems. For example, in the cutscene where the Tornado 2 lands on the Egg Carrier, the metal screeching sound plays before the Tornado actually touches the Egg Carrier. This doesn’t happen in the Dreamcast version. The Dreamcast version also has a few sound problems like that (for example, the sound of the Tornado crashing in Tails’ opening cutscene plays too early and gets cut off), but SADX has many more.
The ports have code bugs in the positional audio system that cause some sounds to never play ingame. In addition, some sounds were deliberately removed or disabled. It’s difficult to talk about all of them in detail, but here’s a list of SADX sound bugs that weren’t there in the Dreamcast version (this isn’t a complete list, also some of these were reported to me on Sonic Retro forums before I started working on the Sound Overhaul mod):
- The spindash sound gets cut off if you have the Light Speed Dash upgrade.
- In the cutscene where Knuckles attacks Sonic, Sonic says “Whoah!” before jumping backwards. It isn’t heard in SADX because Sonic’s soundbank isn’t loaded by that cutscene.
- A thud noise is missing when Sonic (or Tails) and Knuckles run into each other and drop the Chaos emeralds before Chaos 4 emerges.
- The water splashes made by Chaos 4 are muffled by another sound that was mistakenly set to stereo, which interferes with the positional audio system.
- A skid noise when Beta backs up just before his first boss battle is missing.
- A foreboding noise when ZERO’s shadow casts over Amy in the cutscene after Twinkle Park is missing.
- The cutscenes in Amy and Gamma’s story where Gamma lets Amy escape load the wrong soundbank, which causes the cutscenes to either be silent or play random unrelated sounds.
- Bush rustling in the Angel Island hub no longer loops, although the sound is still there.
- The rings that NiGHTS takes you through in Casinopolis’ NiGHTS pinball game no longer make a sound as you travel through them.
- The bombs dropped by the airplanes in Ice Cap Act 3 no longer make a whistling sound as they fall down, and their explosions are silent.
- The sound of collecting rings is in mono instead of stereo – this is because the sound file itself was converted to stereo. The game alternates between the left and right channel when playing this sound, which requires it to be in mono.
- In Sky Deck Act 2, Eggman’s announcements when the ship changes altitude (“Descending into the clouds; slow the ship down!” or “Go up! Full speed ahead!”) are no longer heard because they were removed from the Sky Deck soundbank. The game still plays them if the sounds are put back into the soundbank.
- The ambient machinery noise at the Mystic Ruins Final Egg base is missing – the noise sound was replaced by a single beep, and the function to play the noise was disabled in code, probably because the developers realized that the replacement was annoying. It’s unclear why the original sound was replaced.
- Hot Shelter loads the wrong enemy soundbank, which makes badniks like the Egg Keepers play the sound of the ocean.
The Chao soundbanks were replaced in SADX because the Chao system itself was changed to be more like SA2B. We talk more about Chao-related downgrades on the Chao Gardens page, so here let’s focus on the sounds. It’s hard to compare sounds directly because the soundbanks are very different between SA1 and SADX. Nevertheless I found some identical sounds that we can compare. Which one do you think sounds better?
Finally, let’s discuss the ADX playback downgrade in the Steam and Dreamcast Collection ports. Sound quality in the 2010 ports is undeniably the worst among all versions of the game. Unlike SADX Gamecube and PC 2004, these ports have the opposite problem with sound volume. The background noises drown out almost everything but the music (example: try playing Casino Act 1, where even the music is barely audible because of the gushing water noise). There’s also something noticeably wrong about sound quality. I originally assumed those problems came from the sounds themselves, but apparently it’s a bit more interesting.
The 2004 PC port uses WAV sound effects stored in DAT soundbanks, while the 2010 version uses the same soundbank format but with ADX sounds instead. The soundbanks themselves are identical between the Steam, PSN and X360 versions. When I extracted the soundbanks and tried playing some of those ADX files, I noticed that they sounded better in the audio player than in the game. Why does the game play them like that? I can’t say for sure but here is a possible explanation:
ADX is a closed-source lossy ADPCM-like format, which uses a prediction-based algorithm for decompression. Perhaps there was a precision error either in the game’s programming or with how the sounds were originally encoded, and they ended up sounding inaccurate ingame. Maybe they were encoded with one version of the algorithm, but the game uses another. I’m getting similar results with some tools.
Here’s a sound from the E_0001 soundbank that plays when Chaos 0 is defeated. This is how it sounds if the ADX file is decoded with an old tool called adx2wav. It sounds like that ingame too:
And this is how it sounds when decoded with vgmstream:
The same sound from the 2004 port for comparison:
To test my guess, I set up scripts to convert all soundbanks from the Steam version into the format supported by the 2004 PC port – these scripts are now used in my mod installer. The quality of sound effects in the Steam version is about the same as in the 2004 PC port, though many sound issues from the 2004 port remain unresolved. Unfortunately the Steam and nextgen console ports of SADX fail to play these sounds in their original quality.
To fix sound problems in the PC version of SADX, I went through all sounds in the Dreamcast version (except Chao-related soundbanks) and converted them into a format supported by the 2004 PC port with proper looping where necessary. I’ve also adjusted the volume of background noises, added processing effects to several sounds and restored many missing sounds. The majority of sound issues mentioned in the blog post is now fixed in the 2004 PC port with the Sound Overhaul 2 mod. To learn more about mods for the PC version, visit the “Fixing the PC version of SADX” section on this blog.