For a project I'm working on, I'm considering the idea of making my game try to emulate the capabilities of a SNES game as much as I can.
When trying to decide how much I want it to be as if it were a SNES game versus just emulating a game of that era, I need to know what some of the actual limitations are.
I've got plenty of information available for creating era-accurate graphics, but I can't find out quite what it would take to replicate authentic sound effects.

Now there's a myriad of places and programs for create "chip sounds" but they are geared toward older systems. I've seen a lot of folks trying to create SNES music and so there's a lot of info posted about that as well.
But I can't find information about creating SNES-style sound effects.

I saw some posts on this forum suggesting there are some people here who know what they are talking about, so I thought I'd join and ask here.

I've been listening to the sounds in a number of SNES games, and a lot of them actually sound like real audio; certainly there are a number of them that actually are taken from real audio recordings, but they are also clearly not at the same high quality as sounds I might use today.
What limitations does a SNES sound effect have? If I were to use a high quality sound file, what would I need to do to it to make it have the correct attributes of a SNES sound? And what sort of other limitations would I face, such as maybe how many active sounds can be loaded into memory at any given time?

But there are also a lot of sounds in SNES games that do not sound like they came from recordings, a lot of generated sounds. How could I create sound effects like those? Like I said I've seen programs geared toward creating older chip sounds, but not anything for that generation. I don't even know where I could begin to create the sounds that didn't resemble any true sound in the real world.

I would like a detailed understanding of what sound was capable from that system, and what was commonly done for creating sounds.

I don't know if you've already seen it, but you might be able to get some information from the topic "Help! Trying to create classic SNES sound." It is, as you mentioned, more focussed on music rather than sound effects, but there's some discussion of the hardware and limitations which should also apply at least partially to the sound effects.

I'm sure more direct feedback will also be provided if that doesn't help you though.

Many of the SNES sounds were sampled (i.e. recorded) sounds that were greatly reduced in fidelity so they'd fit into the game. What I'd recommend doing is getting some source sounds you like then use an audio editor to downsample the sounds. You'll notice the sounds will become grainier and distorted. If you don't have an audio editor or access to sound source files, then I'd suggest reaching out to one of the many audio providers on GD.net and see if they'll be willing to take this task on for you.

Thanks!

Nate

I don't know if you've already seen it, but you might be able to get some information from the topic "Help! Trying to create classic SNES sound." It is, as you mentioned, more focussed on music rather than sound effects, but there's some discussion of the hardware and limitations which should also apply at least partially to the sound effects.

Yeah it was that intelligent thread that prompted me to post here.

What I'd recommend doing is getting some source sounds you like then use an audio editor to downsample the sounds.

I figured that's what I'd be doing, but I don't know exactly what specs to which it needs to be downgraded. I tried altering a few by taking the sample rate down to what I read the system was capable of, but it barely sounded any different. I turned the sample rate as low as I could but all that did was make the sound muffled and a little bit like an AM station. It doesn't match the right sound at all, in fact it lost a lot of the tone and clarity that I CAN hear in many SNES sounds.

I'd also be interested in other limitations the system faces. What I imagine is the case is that the system can support some pretty clear audio, but it comes at a cost which leads most games to have only select sounds use such quality. For example, the main character may grunt when he is hit, which on some games sounds very clear and realistic, while the other sounds are a bit more generated and grainy. Knowing the precise limitations helps me figure out how the sounds should arranged.
I mean, Tales of Phantasia had mother-lovin' dialogue spoken, but the other sound effects were practically simple chip tones.

Here are a few hints:
The SNES had an 8-voice, very simple sampler as its synthesizer. All the samples had to fit into 64kbytes (though that was 3.5:1 compressed data, so the equivalent of about 220k)

It is not a matter of taking studio-produced music and downsampling it. Rather, you need to use the same kind of synthesizer to make your music as was in the SNES.

Create your own instruments and use them in a sampler with only very simple features (no filters, etc..just plain audio playback with a simple loop).
Create extremely short loops. If you want to be really accurate, limit the size of your entire palate to around 150kbytes. (yes, Kilobytes).
So the sum total of the size of bass, drums, brass, strings, etc for a single song can't exceed around that amount.
It's that limited palate size that gives the SNES its sound; the SNES had only 64k of sound ram to fit all the instrument sounds and sound effects.

In order to get the instrument sounds that small, you need to create tiny loops and downsample very low (maybe have some instruments go as low as 8 or 12kHz), and then truncate them to 8-bits.
Finally limit your polyphony to no more than 6 notes. That's what we typically used (which left a couple channels open for sound effects).

You are exactly correct about certain "select" sounds being 'high fidelity'... We'd take the important sounds and leave the sampling rates of those fairly high (eg around 22kHz). Of course when you do that, they are bigger, so other sounds have to be made smaller, either by making shorter loops or by downsampling.

Brian Schmidt
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That does clarify things a bit, although, you are talking music again, and I'm making a point about the sound effects. Granted, they are run by the same system, but you'd take a different approach for them.

How could I get the same synthesizer as what's in the SNES? The only thing that comes to my mind is some sort of emulation software, but I'd have no idea what to do with it. I've never seem anyone make a program that creates synthesized SNES sounds, and that would be far beyond my ability to create one.

I've taken a few sample sounds and tried to compress them to a smaller size, and for an individual sound 64 kb is starting to seem generous, compared to my expectations. I grabbed a few sounds to test with, and once they were trimmed down to a little less than a second, I got the .wav file to fit in that size with a sample rate of 32000 with 16-bit resolution. I can't honestly tell the difference in the sound quality at that rate. And for a very quick sound (about 0.11 seconds) I could keep it at its original quality and it only takes up 11 k. I tried some other file formats, but couldn't find anything relevant that made any distinct changes to the file size.

There's certainly something I'm missing about the compression and resolution that I don't know how to set.

Sound effects on SNES had to use the same sound RAM as music.
So very often a SNES sound effect isn't a 'recorded sound effect' at all, but is instead a little MIDI score using some particular timbre/patch.
So instead of having a 3 second trumpet fanfare as a 3-second recorded wav, it would be a very short MIDI file (the notes of the fanfare), to play a very small trumpet patch.

For the SNES games I did, most sound effects were like that-- little MIDI sequences, rather than digitized effects. (exceptions were things like Madden "football collision" sounds, weapon sounds, etc.).

I did leave out that the SNES synthesizer compressed data to Nintendo's proprietary ADPCM format. Not really a good way to duplicate that, though you could try using something like IMA ADPCM.

There's no real way (short of an emulator) of getting the SNES synth, but like I said, if you use a generic sampler, and turn off all the bells and whistles, and make your instrument loops REALLY small (eg a trumpet patch might be a 2kbyte loop), you'll probably start to approach the SNES sound.

Remember, that a game level's ENTIRE sound package had to fit in that 64k. So although you are technically correct that a 32kHz 16-bit wave file would allow you to have one full second of sound effect, that would leave no room for anything else. So we never did that Even the very quick sound-- that one "very quick" sound you use in your example wold have taken up almost 20% of all the sound RAM.

Do you have some examples of "Classic SNES sound effects" you have in mind?

Marcaleb - it would be helpful to be able to see this project, if you're willing and able, so we can make further recommendations. In some cases you don't have to completely emulate the actual make up of a retro console but, rather, get close to the basic idea but using more modern techniques. Other times a unique fusion of low-fi and high-fi elements can create a cool presentation of the game.

I can't speak to the SNES as I was in elementary and middle school when it was out (sorry Brian! ) but I've worked with several guys that did stuff for PS1 and PS2. Even with those more recent consoles they had to create multi-functional sound elements which could be blended together to make "new" sounds in the game. So much of what made retro..... retro was dealing with extremely small storage space. I know that when I was working in Nintendo DS titles I would recycle instruments from cue to cue (with some changes) to help keep music space as small as possible. Then using the MIDI-sample-bank method that Brian mentioned I was able to get 10+ levels of music crammed into a VERY tiny amount of space. It was a pretty fun challenge actually.

Which brings to mind:

"My freedom will be so much the greater and more meaningful the more narrowly I limit my field of action and the more I surround myself with obstacles. Whatever diminishes constraint diminishes strength. The more constraints one imposes, the more one frees one's self of the chains that shackle the spirit."

- Igor Stravinsky

Remember, that a game level's ENTIRE sound package had to fit in that 64k.

Ah, well that makes a difference.
Either way, switching to 8-bit resolution and and dropping to a lower sample rate doesn't seem to be quite replicating the proper quality of sound. It mostly makes the sounds more muffled. But I can't think of any other way to reduce the file size, or at least I can't find any other relevant changes that I can make with my software.

Do you have some examples of "Classic SNES sound effects" you have in mind?

Well I ran through a gamut of different games, listening to the sounds to figure out what I was looking for... The first thing I noticed was that many many many of those games had sounds that were far too realistic to be synthesized. Doors creaking, footsteps, cries of pain, many explosions...
I guess I could put a few samples together, but the point remains that they used a mix of sounds that most likely were sampled, and others that might have been sampled or synthesized, I can't honestly tell. But all the sound synthesizing programs I can find simply can't create anything that has the fidelity range to sound like it might be a distorted real sample.

Marcaleb - it would be helpful to be able to see this project, if you're willing and able, so we can make further recommendations.

Well I can post a link to a page I made for it, but that's not going to show much relevance to the particular discussion. What I should be clear on is that right now I'm investigating the possibility of an adamant retro theme.

It's more than anything else about finding something withing my capabilities to create. Earlier I was planning on using a hand-drawn theme, but I got a few tests put together and it looked like crap. Well what else could I do? Hey, why not go with a retro theme? Sure, I'll bet I can do that.
I've done a few art tests and that's looking well, so now I'm moving down the line to the sound. So I face the question: can I create sound that matches this theme? If I can, I'm moving forward. If I can't, I'm finding something else.

And certainly, there is no law that says I can't use retro-style artwork with modern quality sound, but that's not quite the way I work.
I absolutely HATE IT when I see people makes games or other media that is supposed to be retro -that are supposed to create what was seen in a certain era- but botch the thing into some talent-less monstrosity. Look, if you're going for a retro style it is because you are trying to appeal to the people who grew up loving and playing those games. And those people knew what sort of things those games were capable of; we lived in that era, and watched games grow, and got blown away by what they became.

So if I go for a retro theme, I'm going to go for whole-hog, and make it look indistinguishable from the games of the era. Or if I go for something that's just retro-inspired then I'm going to whole-hog with that and thoroughly blend modern capabilities into retro ideas so that it is obvious that such was my intent. And if I go with some other non-retro theme, then I'll whole-hog with that, whatever it might be.
But I will NOT create one of those monstrosities that tries to appeal to the retro crowd, but can't figure out if it's trying to be something from the Atari, NES, or SNES.

Other times a unique fusion of low-fi and high-fi elements can create a cool presentation of the game.

Oh that's something that's on my mind too, believe you me.

FYI, I wrote a Gamasutra article on this technique (mixing high fi and low fi assets to create complex sounds.).

http://gamasutra.com/blogs/BrianSchmidt/20111117/90625/Designing_the_Boot_Sound_for_the_Original_Xbox.php

Another thought:
It might be that the "sound" you're looking for is related to the ADPCM compression.
Try compressing the sound with ADPCM,and then un-compressing it again.
Also, before we downsampled, we'd usually tweak the sound (boosting some highs) to try to recapture some of the brightness that we knew we were going to lose.
Or we'd eq the highs back up after downsampling as much as we could..

Brian Schmidt
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