How to make ym2612 instruments?

[djcouchycouch]

Hi,

Now that I can play music and sound effects in Goplanes, I'm in the process of figuring things out to actually go and compose new original music and sound effects. One place I'm a little stuck on is with instruments. Short version: I have no idea how to make them.

I don't want to take them from other songs since I feel that there are probably certain copyright issues there that I don't want to deal with. (like "hey! you stole my drum sounds!")

So does anyone know of resources I can look at to get an idea?

I want to be able to answer questions like: how do I make a guitar sound? how do I make a drum sound? how do I make a piano sound? You get the idea.

Thanks!
DJCC

[Chilly Willy]

If you aren't much for making your own FM instruments, get this. It has a BUNCH of different FM instruments.

[fletto]

Hi,

Now that I can play music and sound effects in Goplanes, I'm in the process of figuring things out to actually go and compose new original music and sound effects. One place I'm a little stuck on is with instruments. Short version: I have no idea how to make them.

I don't want to take them from other songs since I feel that there are probably certain copyright issues there that I don't want to deal with. (like "hey! you stole my drum sounds!")

So does anyone know of resources I can look at to get an idea?

I want to be able to answer questions like: how do I make a guitar sound? how do I make a drum sound? how do I make a piano sound? You get the idea.

Thanks!
DJCC

Hey there DJCC,

I guess the quick-and-dirty answer to this is: Take a VGM file which contains the instrument you want, look at the register values, and tweak them around a bit so it ain't an exact replica of the original (although I don't believe anybody would hit you with a copyright complaint if you _did_ shamelessly clone the instruments.)

But as always, there's the hard way which achieves better results.
(I'm assuming you don't have previous background on audio physics)

The 'signature' of a given instrument, or any sound for that matter, is its harmonic content as seen here:
http://www.phy.mtu.edu/~suits/sax_sounds/index.html

Notice how the spectra relate to our 'feeling' of the saxophones.

FM synthesis create a set of smaller harmonics around the output operator's (AKA carrier) frequency, as described here:
http://www.soundonsound.com/sos/apr00/a ... ecrets.htm

The replication of a physical instrument on a YM2612 requires looking at the desired spectrum, finding a couple major formants, and then trying to come up with modulation levels that will better approximate that harmonic profile.
Since that is pretty damn tough and time consuming, people prefer 'genetic' (random computer trial-and-error) algorithms:
http://forum.dmc.ntnu.edu.tw/~wocmat2006/pdf/2-3.pdf

Last but not least, composing an interesting tune is not as hard as it may sound (pun intended), pleasant Western music revolves around simple four chord progressions, demonstrated here:
http://www.youtube.com/watch?v=R2De2cK1 ... plpp_video

The entire Warbeats video series is great, it teaches you the most important topics in writing good sounds without getting too technical:
http://www.youtube.com/user/nfxbeats/videos

Bobby Crispy teaches riffs and techniques on the Harmonic Minor scale (which gives hard rock and heavy metal their distinctive sound:)
http://www.youtube.com/watch?v=IKBBocFl2vI

Okay, hope that gives you a push in the right direction.

[fletto]

If you aren't much for making your own FM instruments, get this. It has a BUNCH of different FM instruments.

Yep, that's even better than my VGM dump idea. I never tried tfmmaker 'cuz I wouldn't run Windows even if my life depended on it and it doesn't run well on Wine.

[neologix]

fletto has some great advice, especially regarding the science and theory of it. Given my personal experience w/the YM2612 I have some practical advice that I'll edit into this post as I think of it.


edit 1:

Learn how the 8 available operator (aka "slot" or "op") configurations (aka "connections," "algorithms," etc) work and how much OP1 self-feedback will affect the overall resulting sound at the end of the chain; when in doubt, use configuration 8 which replicates a purely additive synthesis connection. You have four operators to work with, and ignoring OP1 feedback and with the exception of algorithm 8, every algorithm has at least one operator being modulated by another. A visual diagram of the 8 connections can be found here. (edit - apparently operators only become "slots" when their output is directly added to the final result)

Each operator has a volume envelope; learn how the envelope will affect the attenuation (an engineering term, kinda like the inverse of volume in this case) and when. The vast majority of configuring an operator is configuring its volume envelope, and there are 6 separate registers per operator that handle 9 different pieces of the envelope:

• TL: total level (aka "attenuation," the maximum volume of this op's envelope)
• RS: rate scale (aka "do higher pitches affect the speed of the envelope")
• AR: attack rate (how quickly volume reaches the total level)
• AM: amplitude modulation (aka "does the LFO affect the envelope")
• D1R: decay rate (how quickly volume reaches the sustain level)
• SL: sustain level (once reaching this level, switch to secondary decay)
• D2R: secondary decay rate (aka "sustain rate," or how quickly volume decays to 0 while key is still on)
• RR: release rate (how quickly volume decays to 0 after releasing the key)
• SSG: secondary sound generator (aka "SSG," a secondary envelope generator that is rarely used in Genesis audio but can produce some interesting effects to the overall sound when used properly)

There is also a register that controls the frequency of the operator (both coarse and fine detuning) with relation to the base frequency. This relationship is the basis of FM synthesis theory and proper configuration of it combined w/configuration of the volume envelope will determine the base timbre of your resulting sound and how it's affected over time.

more to come later.

[djcouchycouch]

Wow, that's a lot of stuff! Thanks guys.

Thanks for all the theory, fletto!

I had no idea tfmmaker came with so many instruments! A large part of the reason I was asking to make them was because I couldn't find any. I'll definitely look into those. Are they free to use? Do they have any licensing? Are there other instrument sets available elsewhere?

DJCC

[fletto]

Wow, that's a lot of stuff! Thanks guys.

Thanks for all the theory, fletto!

Hey, it's always a pleasure to support talented fellers like yourself.

I had no idea tfmmaker came with so many instruments! A large part of the reason I was asking to make them was because I couldn't find any. I'll definitely look into those. Are they free to use? Do they have any licensing? Are there other instrument sets available elsewhere?

DJCC

I found a couple of unused FM 'recipes' I created myself and didn't use on any proprietary projects, get them here:

http://tsdmedia.com/segastuff/FM_insts.zip

You might find the 'powerchord2' and 'slapped bass' instruments the only ones really useful to get a tune going, but hey, it's a start.
I converted them to Deflemask format (www.deflemask.com.ar), it should be pretty straightforward to retrieve the register values. Standard Redneck Licence: "They is free f'y'all tah use, by Gawd"

[Delek]

I never tried tfmmaker 'cuz I wouldn't run Windows even if my life depended on it and it doesn't run well on Wine.

If you are in Linux, you could use the Linux build of DefleMask, a tracker that supports, among other systems, SEGA Genesis.

I'm working in the OS-X build right now.

Regards.

[fletto]

I never tried tfmmaker 'cuz I wouldn't run Windows even if my life depended on it and it doesn't run well on Wine.

If you are in Linux, you could use the Linux build of DefleMask, a tracker that supports, among other systems, SEGA Genesis.

I'm working in the OS-X build right now.

Regards.

Thanks for the tip, Delek, I already came across your (excellent) tracker and used it to create a couple instruments for our buddy djcouchycouch.