Retro Game Audio

Aug 25

Can you explain what it means, exactly, for music to be “8-bit?”

Can you explain what it means, exactly, for music to be “8-bit?” What significance does the number of bits have for waveforms, channels, sample size/quality, volume, speed, etc? In other words, the number of bits limits _____ to _____?

This is a great question, I’ll try to answer as best as I can.

1. What is 8-bit music? 16-bit music?

In general terms, I’d argue that these titles are meaningless by themselves. A lot of people associate “8-bit” with things that sound like the NES, but the problem with this is that the NES doesn’t primarily sound the way that it does because it’s 8-bit, it sounds the way it does because of the particular kinds of sounds it uses.

It’s not that the limitations don’t matter at all, the NES would have had different audio if the system belonged to a different ‘bit generation’, but here’s an example of why these titles don’t mean much on their own:

Let’s say you have a 16-bit wave file of CD music and you convert it to 8-bit. Is the end result something that sounds like the NES? Not at all.

This is why specificity matters. Classic video game systems sound the way they do because of the approach to building or creating sounds. Is the system using sound synthesis? If it is, is it perhaps using subtractive synthesisFM synthesis, or wavetable synthesis? Or is the system playing back samples, or some combination of different kinds of synthesis and samples?

Once you determine these distinctions, this tells you why a given system sounds the way it does.

2. Another way of putting it, is that systems can sound similar or dissimilar regardless of which bit generation they belong to.

Another way to illustrate my first point would be to share a few examples. Consider Amiga music:

This is 8-bit music, but it doesn’t sound anything like the NES. This is because it is music that’s sample-based, making it more comparable to the SNES (SNES uses 8 channels of 16-bit sample playback, Amiga uses 4 channels of 8-bit sample playback).

Another good example is the Virtual Boy.

A while back, I was trying to find out more about the audio behind the Virtual Boy, and was disappointed to find that most sites, including wikipedia, had nothing more to say than “16 bit stereo audio”.

That doesn’t tell me practically anything. The SNES is also 16-bit, as is the Sega Genesis, which all sound different from each other (it turns out that the Virtual Boy uses 6 channels of primarily wavetable synthesis).

Last but not least is the Game Boy. It is the closest thing there is to the NES in terms of audio, but it’s 4-bit, not 8-bit.

3. But the bits do matter…

Before I give the false impression that the ‘bit limitations’ of a system aren’t incredibly important to the sound capabilities (too late?), I’ll need to clarify that the amount of bits available that can be manipulated are the be-all end-all of what you can do.

Then why spend so much time downplaying the titles of “8-bit” and “16-bit”? It’s because these titles can be misleading, as they often don’t tell you about the specific limitations of different parameters.

THE NES / Famicom

Let’s consider volume on the NES. If we were to assume that the NES was 8-bit everything, then we’d expect there to be 256 different possible volume settings for a given voice. But that’s not the case, the channel volume is determined by a 4-bit value, allowing 16 possible volumes (0-15) for the pulse waves and noise channels.

What does this mean in musical terms? Lower bits means less resolution. Let’s say you wanted to have a note fade out. If you start with a high or medium volume, you have room to descend and your ear will hear a smooth-enough fade out. But if you started with a quiet note and wanted to do a long fade out, there are no values in-between what’s available. If you go from volume 3, to 2, to 1, and then 0, and you don’t do this quickly, you won’t hear a smooth fade out at all. The volume will distinctly “jump” between those values, with no means for a smoother fade (unless maybe you try to cover it up with other sounds at the same time).

There’s also the sample channel on the NES. Those samples aren’t 8-bit either, they’re actually just 1-bit/ 7-bit… (more on that in a future post)

A quick search on the NESdev page that details the NES APU will yield 5 matches for 4-bit and 0 matches for 8-bit. Go figure.

Wavetable Synthesis

Some systems use wavetable synthesis, which in layman’s terms is a sort of free space to draw whatever waveform you wanted. In software, it often looks like a bar graph.

-The Game Boy allows for a table of 32 4-bit samples to create a waveform (in one channel).

-The Virtual Boy allows for a table of 32 6-bit samples to create a waveform (in five channels).

-The Famicom Disk System add-on adds one additional channel to the Famicom that uses 64 6-bit samples.

Even though these are all examples of wavetable synthesis, the bit-limitations create sounds that are distinct from each other. In a future post, I may compare the wavetable synthesis of these three systems more closely. The basic summary is that the lowest resolution of the three is found on the gameboy, which has the “dirtiest” sound. By comparison, the Famicom Disk System can create some very smooth sounds.

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I hope this answers your question. The number of bits limits your resolution, which affects the qualities and potential for all sorts of parameters.

There are plenty of videos out there explaining bit depth for audio samples, or how bits + binary work, though when discussing video game music I think the most important distinction to make is that the “bit generation” a system belongs to doesn’t tell you anything about how it sounds by itself.

pingosimon said: Can you explain what it means, exactly, for music to be "8-bit?" What significance does the number of bits have for waveforms, channels, sample size/quality, volume, speed, etc? In other words, the number of bits limits _____ to _____?

(apologies to those who already saw the above post down here before. I had a request to make it reblog-able. I wasn’t aware “ask” posts couldn’t be re-blogged!)

pancakeinrainbows said: Good to see you haven't abandoned us! I saw your previous video on the Triangle Kick Drums and loved the resulting sound. Can you show us how to use the same trick for augmenting snares? (I have no idea what it's supposed to sound like.)

The same basic trick applies to the snare drum, but it usually involves higher pitches, sometimes with a shorter duration.

If newer readers haven’t seen it yet, you can watch the video in this post for a demonstration of how the triangle wave is used for percussion.

Comparing kick vs. snare triangle effects in several games, I’ve found that the snare sound was actually pretty similar in all of them. The “sweet spot”, at least for these examples, seems to be starting somewhere around G3-A#3, and then pitching down only within that octave, or going down somewhat into the octave beneath but not very far.

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^Asterix Triangle Snare - A#3, G3, E3, F#2

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^Hero Quest Triangle Snare - G#3, F#3

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^Solstice Triangle Snare - G3, F#3

If you want to compare these snare drums to the bass drum sounds used in these games, I uploaded an album showing both:

http://imgur.com/a/hc5ms

If you want to create this effect in Famitracker, be sure to use a newer version (anything since v.0.3.8). This is because older versions of Famitracker don’t have an option in the instrument editor for “fixed” arpeggios. Fixed arpeggios allow you to insert the same downward pitch bend at the beginning of every note, regardless of the note you sustain on afterwards. This way your bass and snare effects don’t change along with your bassline.

pianissimissimo said: Amazing blog, thank you for it! What are your thoughts on the Solstice soundtrack? I think it sounds ridiculously huge and have always wondered how the composer achieved this!

Thank you! Solstice has an excellent soundtrack composed by Tim Follin. He is highly regarded for his “clever manipulation of limited sound hardware”, as wikipedia puts it.

The big sound comes from a combination of techniques; we can use the title theme to demonstrate them.

At around 8 seconds in, we hear an explosion of colorful sounds. It’s a drastic change from the introduction, as if it’s mocking the simplistic sound.

1. Using the Triangle Wave to Augment Percussion

The triangle channel, which is most commonly used for basslines in NES music, is used to make the drums sound a lot bigger and heavier. This is achieved by adding quick downward pitch bends to create bass drum and snare drum sounds (that double up with the noise channel).

If you were to isolate the triangle channel, you would hear that the basslines are clearly interrupted by these percussive sounds. But when everything is put together, your ear is never really bothered by the fact the bass never hits at the exact same moment as a bass drum or snare drum. It’s always a little behind or “in-between”, and the end result is a full sound with big drums.

This previous post explains triangle percussion in more detail, with a video demonstration.

2. The Arpeggio Effect

Rapidly alternating notes are used to simulate chords in the NES’ monophonic channels. To overcome the limitation of not being able to play a chord in a single channel, chords are broken up into their individual notes and changed very quickly.

Solstice doesn’t use this effect timidly, instead it it opens up after the introduction with two different arpeggios stacked on top of each other. At other times, one of the pulse waves may be playing a melody while the other supports it with arpeggios behind it.

More information on this effect here.

3. Dynamics

Including voices that are quiet go a long way in making this track sound bigger. If everything was loud, you’d adjust your speakers accordingly and there’d be little room to go up.

There are more tricks you can identify, like single channel echo and duty cycle modulation, which add a nice quality and detail to the sound. Though overall I think the three things listed above are the most important elements in giving Solstice the large sound that it has.

(back from long hiatus)

Apologies to those who’ve had unanswered questions. I didn’t intend to take such a long break from this blog. I hadn’t logged into my youtube channel or tumblr for quite a while, but I’m happy to discover newer followers and questions being submitted in that time.

I’ll try to answer what questions I can over the next couple days, and hope to start posting again somewhat regularly. Unrelated, here’s a gif I made from Flashback:

-bucky

NES Audio: Single Channel Echo in Moon Crystal

In a previous post, I explored a technique for single channel echo utilized by Neil Baldwin. I wanted to demonstrate another example that’s found in a Japanese game:

Moon Crystal by Tsukasa Tawada features this effect in a couple of its tracks. It’s accomplished by writing a pattern of notes, and then inserting a copy of those notes in-between itself at a reduced volume. In musical terms, it’d be like taking a pattern of 16th notes, then doubling the notes up so that you have 32nd notes instead.

Additionally, to exaggerate the impact of the echo effect, the notes can be shifted so that the quieter in-between note isn’t a softer version of the note immediately before it. Instead, it’s delayed and falls after the next note. Here’s the beginning of the part heard at 4 seconds into the above video:

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The basic melody without echo is shown on the left, what you hear in-game is shown on the right. 8 and 4 are the volumes of the notes (you can ignore the number “15”, that was the designation of the instrument I was using).

The notes (without volume commands) would look like this in sheet music:

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(^before the effect)

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(^after the effect)

May 07

Reader responds: Regarding MSX Audio…

2PLAYER answered my question. You can visit his tumblr here

Channels 7, 8, and 9 have 6 slots and are used to generate the 5 rhythmic sounds. Bass drum uses 2 slots with FM while the other 4 sounds are created using the OPL white noise oscillator combined with frequency data. So yes, you could make your own OPL drums with the 9 channels but this allows you to squeeze 5 drums out of 3 channels.

Thanks for the information! :D

A question for my readers: Regarding MSX Audio…

Hello everyone!

A couple weeks ago I responded to a question about the sound behind the MSX and the Metal Gear 2: Solid Snake soundtrack. But there’s actually something regarding the description of the soundchips in MSX-AUDIO and MSX-MUSIC that I’ve never understood when reading about them. I’d be interest if someone can provide an answer.

According to wikipedia and other sources, both MSX-AUDIO and MSX-MUSIC are described as having:

9 channels of FM sound (without drums), or 6 channels of FM sound + 5 FM drums.

Does anyone know why that is, or what that means? You can create percussive sounds with FM synthesis. And with the Sega Genesis YM2612, for example, that doesn’t require a special feature or different mode. You can use one of the 6 FM channels to make a drum sound as you would make any other sound. 

Is there a reason you can’t use the first 9 channels however you want (ignoring MSX-MUSIC having presets)? Or is it that you can do that with MSX-AUDIO, but they found a way to create drums with less resources, making it better to have an option that allows for 5 channels of drums with only sacrificing 3 “normal” channels? Does that come from restricting the number of operators?

Perhaps I’m simply misreading a feature as a “rule”. With the drums enabled, I don’t understand why you couldn’t have 11 channels of drums. Any clarification would be great!

May 06

NES Audio: Reinterpretation of The Exorcist theme

Visiting a friend in Washington, D.C. this past weekend, we happened to run into the staircase from The Exorcist when I stopped for gas.

I was reminded of an arrangement I did of the “Exorcist theme” for the NES some years back. It’s not the entirety of Mike Oldfield’s Tubular Bells, just the segment popularized by the movie:

It was made shortly after I extracted the Sunsoft bass samples from Gremlins 2. I wanted to have a better understanding on how melodies worked in the sample channel, so I used it in this arrangement. I also hadn’t played around with much triangle percussion at that point, so creating this was a good learning experience!

Apr 21

xitebike3000 said: Can you explain how the MSX2 sound chip works? I was listening to music from Metal Gear 2 and it's got some great sounds.

Sure! Metal Gear 2: Solid Snake on the MSX2 has one of my favorite computer game soundtracks from the 8-bit era. I’m not as familiar with MSX audio as I am with the NES, but I know a little bit about the soundchips they used and the general limitations they had.

A brief introduction:

MSX machines are a family of home computers from the early ’80s. Part of the ‘8-bit’ computer market, MSX competed with computers like the Commodore 64, Atari 8-bit, and ZX Spectrum. They were popular in parts of Asia, Europe, and South America, but mostly unknown in the United States. You can read more about the MSX here and on wikipedia.

MSX2

(an MSX2+ [image source]) 

For audio, the MSX2 primarily used the Yamaha YM2149 programmable sound generator. It is a variant of the General Instrument AY-3-8910, which was used in many other systems like the Intellivision, ZX Spectrum, Amstrad CPC, and more. It is also similar to the Texas Instruments SN76489, the competing chip that was used in the Sega Master System.

The AY-3-8910 Sound Chip

This sound chip has three channels of sound, comprised of square waves and a noise generator (you can read an incredibly in-depth analysis here). This video demonstrates a youtube user’s favorite MSX music made with this PSG audio:

But Metal Gear 2: Solid Snake used a sound expansion cartridge for more advanced audio. Known as MSX-AUDIO, the cartridge contained the Yamaha Y8950, a sound chip that offered 9 channels of FM sound (or 6 if FM percussion is being used), and included an 8-bit ADPCM sampler. If you wanted to compare the audio to another system, it’s kind of like a more primitive Sega Genesis.

Three different cartridges for MSX-AUDIO were made by Philips, Toshiba, and Panasonic. Here’s what one of them looked like:

MSX-AUDIO Cartridge

At the moment I’m having difficulty finding a complete list of games that used MSX-AUDIO in their soundtracks, but I know that Konami had several, including Metal Gear 2: Solid Snake.

Something I like a lot about the Metal Gear 2 soundtrack is how it embraces the synthesizer aesthetic. The introduction to MG2 has one of the most cinematic-like openings of any 8-bit game I’ve seen, and the music has elements of ’80s horror / sci-fi themes. I’m reminded of music by John Carpenter (Halloween, Escape from New York, Assault on Precinct 13) at moments throughout MG2, reinterpreted with a Konami-esque sound.

There was also another sound add-on for the MSX known as MSX-MUSIC, which used the Yamaha YM2413 sound chip. It also offered 9 (or 6+ drums) channels of FM sound, but it was more limited than MSX-AUDIO because it allowed only one customizable voice at a time, with the rest being presets (more information here). MSX-Music was a built-in feature on some of the later MSX models. Fans of the Sega Master System will recognize the sound as the same FM chip used in some Master System games. 

One of my favorite MSX-Music soundtracks I’ve heard is the MSX port of Final Fantasy. I generally expect console-to-computer ports from the ’80s to not do the best job converting the music, but I actually like the MSX version of Final Fantasy more than the original Famicom/ NES version:

The Legacy Music Hour - Episode 77: Sunsoft

Episode 77: Sunsoft

I was invited via skype as a guest on the most recent episode of The Legacy Music Hour podcast. I talk a little bit about Sunsoft audio, their use of melodic samples, and a couple other things. It’s a great episode with some excellent selections by Brent and Rob.

Episode tracklist:

Gimmick! - Masashi Kageyama - Good Morning (Introduction) - Authentic Entertainment/Sunsoft - Famicom - 1992

Super Spy Hunter - Naoki Kodaka, Nobuyuki Hara, Shinichi Seya - Staff Roll - Sunsoft - NES - 1992

Journey to Silius - Naoki Kodaka, Nobuyuki Hara, Shinichi Seya - Stage 3 - Sunsoft - NES - 1990

Batman - Naoki Kodaka, Nobuyuki Hara - Stage 3 - Sunsoft - NES - 1989

Blaster Master - Naoki Kodaka - Level 6 - Sunsoft - NES - 1988

Tel-Tel Mahjong - unknown - BGM 4 - Chat Noir/Sunsoft - Mega Drive - 1990

Fester’s Quest - Naoki Kodaka, Nobuyuki Hara - Outside - Sunsoft - NES - 1989

Super Fantasy Zone - Naoki Kodaka - Staff Roll - Sunsoft - Mega Drive - 1992

Pescatore - unknown - Unknown 1 - Tierheit/Sunsoft - Famicom - 1991 (unreleased)

Freedom Force - Naoki Kodaka - Stage 2: Terminal Walkway - Sunsoft - NES - 1988

Trip World - Tsutomu Ishida, Masayuki Iwata, Atsushi Mihiro, Phase Out - Credits - Sunsoft - Game Boy (Japan) - 1992

Benkei Gaiden - unknown - unknown - Sunsoft - PC Engine - 1989

Hebereke - Naoki Kodaka, Nobuyuki Hara, Shinichi Seya - Hebe’s Adventure - Sunsoft - Famicom - 1991

Tel-Tel Stadium - Shinichi Seya - Sound Test 0B - Sunsoft - Mega Drive - 1990

Batman: Return of the Joker - Naoki Kodaka, Nobuyuki Hara, Shinichi Seya - Ending - Sunsoft - NES - 1991

Apr 07

NES Audio: The Arpeggio Effect

A brief explanation and several examples of the arpeggio effect.

In an earlier post I talked about the arpeggio, and gave more specifics about how it works on the NES, although I wanted to make a youtube video with more examples. :)

Apr 06

The Legacy Music Hour podcast

http://legacymusichour.blogspot.com/

http://itunes.apple.com/us/podcast/the-legacy-music-hour/id405561057

The Legacy Music Hour podcast was created by Brent Weinbach and Rob F. for the purpose of sharing and talking about video game music from specifically the 8-bit and 16-bit eras. No remixes, no covers, no video game inspired music -just pure, original music from the NES, SNES, Genesis, and more…

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I’d like to thank the guys from the legacy music hour podcast for the kind words and sharing retrogameaudio with their listeners in the last episode. I’d also like repay the plug by recommending The Legacy Music Hour to my followers on tumblr. Check it out!

I’ve been digging through their archives and I’ve discovered some awesome game music. I really appreciate the show and I’m looking forward to tuning in weekly.

Apr 05

[video]

Mar 30

NES Audio: Legend of Zelda, video display of sound channels

created by: 1ucasvb

I found some cool videos that show the waveform display for each sound channel. It’s a very nice way of demonstrating how the music is arranged.