Monday August 20, 2012 20:14

Phantasy Star Online 2′s Dynamic Music System “SYMPATHY”

Posted by Ricardo

At CEDEC 2012, Sega Research And Development Team (including PSO2 sound director Hideaki Kobayashi) discussed the concepts behind how PSO2′s music is procedurally generated.

This process is done through an in-house program they call “SYMPATHY.” It allows them to dynamically change the music back and forth depending on the situation.

Now this kind of article discusses the concepts behind the music which can make it somewhat hard to understand. So if you are not a music major, you’ll have to brush up on certain music terms.

Basically, each sound file is known as a “clip.” A clip is approximately the length of 1 bar of music. When you place many of these clips together, they become a “phrase“. When you connect these phrases together they become a musical movement (Here we go!). We can refer to these movements as sections of a song. When you connect these movements together they become “Parts“.

(Though they didn’t specify, a “part” could be the entire song itself, possibly the entire non-battle portion makes up one part of the song, and the entire battle portion makes up another part of the song. Parts however do not play the same way when looped as will be explained further on. )

In the slide above, if you check out the right side of the pic, each large box is a subsection of the box below. So several clips make up a phrase, a line of phrases make up a movement, a line of movements make up a “part.”


Clips are the length of 1 bar of music plus reverberation. Basically each clip will fade into the other clip. PSO2 can have several thousands of these clips and the Sympathy system can arrange it all.

There are various clips that contain different components of the song. A clip can consist of the “rhythm section”, the “melody” and “sound effects” etc.


Phantasy Star also has transition music where the song switches from one mode to another. If you follow the red arrow, the non-battle music heads from one phrase to the transition music then exiting out to the battle music.

PSO2′s music system has even evolved from its previous counterparts. For example, in PSO1, after the battle portion of the music ends, and you immediately encounter a different enemy, the non-battle music would play for a while.

In PSO2, there’s another musical piece known as the “Sudden Battle Music” that can be inserted mid-way.

To illustrate this, at the top of the slide the battle music is playing, after the battle is over, it starts to play the transition music when suddenly, another enemy appears. It will then quickly play the “Sudden battle Music” to transition into the battle music.

There’s three main points to SYMPATHY’s music system. For one, its intent is to prevent the player from losing interest. Since they will play similar quests multiple times, they may lose interest when the same BGM is played over and over. The SYMPATHY music system allows them to play a different BGM every time. We can illustrate this in the next slide.

They can:

  • Shuffle the different sections of music,
  • Skip different sections of the music.
  • Skip different phrases of the music.

They can even choose clips at random, and also prevent the same clips in succession from being chosen when a part of the song is looped. (It could play one set of clips, then loop, play another set of clips, etc..)


This slide shows an example of Sega’s Symphony Music Editor.  The boxes are clips, the red boxes are clips currently chosen to be played. When a part of the song is looped, the clips get shuffled.  The red frame is the sound effects,  the yellow and green frames are rhythm portions.

The second point of Sympathy is for the player to experience the climax of the BGM. (But not in that way you’re probably thinking… ) Basically the BGM changes depending on the situation. This is calculated through three parameters, “Hero,” “Pinch,” and “Climax.”


According to this slide, a number of things can affect these parameters. For example, the  Hero score is affected by things like PSE BURST, the number of people in your party and other parties, the mid boss enemy strength, and boost enemy strength.

The enemy strength, character’s HP, and party member HP influences the Pinch score.

The number of nearby enemies, how long until you reach the goal, and emergency trials factors into the Climax score.

This lovely debug window shows the three scores which are updated in real-time to affect the BGM.

When you surpass a particular level in each parameter, that parameter’s music gains priority. For example, when your hero levels are high enough, you’ll hear clips that only play during that mode. Same goes for Pinch, you’ll hear music specifically for that situation.

Another way to illustrate it, normally you’ll hear the rhythm and melody clips playing, when you acquire hero mode, the melody track is dropped and instead plays the hero clips. If you are in pinch mode, all tracks are dropped and only the pinch clip plays.


The Boss music is dynamic too. For example, you’ll hear the normal boss music when you encounter the boss, but if you happen to take down one of its legs, another set of clips will play.

The third concept was a little bit hard to understand but the gist was that even though the music is played at random, everything should sound like one musical composition. Meaning each section should still sound like it’s from the same song, and these sections should connect and reference each other.

Even in pop music, as the song moves forward, the previous theme is referenced. Sympathy does this automatically.  The phrase used at the beginning of a section is referenced in the next section.

As we go from battle to non battle music, in essence it should sound like one musical composition as the music changes. While this change is occurring, it references the first phrase in the battle music and the last phrase in the non-battle music.

[info and pics via 4gamer]

Odds and Ends

  • Sakai will update twice this week.
  • Since they asked nicely, you can hear me in episode 8 of the EXP FULL podcast. Check it out!
  • September: Three New Classes and Five New Weapon Categories
  • Planned for October: Level Cap 50 and _ _ B  _ LASS. Yes they’re coming, just have to wait a bit longer.
  • Sending out a nice round of thank you emails this week! Heading back to school next month! :S

30 Responses to Phantasy Star Online 2′s Dynamic Music System “SYMPATHY”


August 20th, 2012 at 6:46 pm

Thank you, Ricardo! ^.^ You come through yet again!


August 20th, 2012 at 6:58 pm

Really interesting stuff, thanks, actually seems to work kind of similarly to the RAH system in Ar Tonelico, in terms of pure coding


August 20th, 2012 at 7:02 pm

Well this shoots a number of my theories out of the water, Oh well. Here's some of the research I did back during alpha. It may not be Sympathy, but it opens some possibilities maybe.


August 20th, 2012 at 8:01 pm

i think this system they made may be partially to blame for why a lot of the time i feel like the music just sounds like it's got way too much shit/noise/sounds going on.

there should also be a future option to prevent battle music from turning on, because there are a few stages where i like the ambient music only, and the battle music is just no good.


August 20th, 2012 at 9:01 pm

the big problem with this system is that it ultimately creates a boring, repetetive kludge of a soundtrack. I hardly get to hear the basic music for a region because every time enemies show up, it either immediately kicks into the DUN DUN DUNNN BAD GUYS ARE HERE! track or worse, the "pinch" track that's the same everywhere and grating everywhere. the soundtrack feels lifeless due to this all, and the lobbies/bossfights/victorytheme are the only really memorable bits. and I suppose the obnoxious "pinch" track if only because the game spams it in your ear so much you're forced to remember it.

hell, I can stand still as the only person on a map and sometimes it'll still go juggling moods for no reason.

it's kind of silly when I'm wandering the desert, and everyone's HP is full, the party has been buffed, and because two of the little tiny cannon fodder darkers spawn, the game decides IT'S TIME FOR THE "Pinch" TRACK!!!, which also robs the track of it's identity-of-purpose. instead of being the "oh crap" track it becomes just another irritating piece of the background noise.

give me normal music tracks any day.


August 20th, 2012 at 11:25 pm

Wait there are new classes in September? I thought we were only getting Sub Classes?


August 21st, 2012 at 1:12 am

I think the SYMPATHY system actuall limits the quality of the compositions quite a bit. It ends up really just being background music. Wheras most of the field songs from Universe were so good that I never tired of them (and have the full soundtrack.) I don't think SYMPATHY could pull off the track Raffion Medow, or the track that plays in parums first ancient area. Those are masterfull compositions, well timed themes and climaxes that work because the entire peace builds carefully towards them. SYMPATHY makes everything a bit of a mash, and even themes I want hear (which aren't many, most of it is just bleh so far) I can not expect, nor are they particularly well prepared for musically.


August 21st, 2012 at 1:15 am

PS, SYMPATHY does make compositions on par with most bgm tracks from the PSO games… which is a much lower bar than PSU. Still I have yet to hear anything better than the best field tracksfrom PSO. And I have not heard anything close to the non field tracks from PSO


August 21st, 2012 at 2:57 am

Too bad the devs got it all wrong, this Sympathy system is utter crap and completely ruins the atmosphere overall. I want fixed tracks and memorable music, not this pile of dirt =/


August 21st, 2012 at 3:51 am

Not fixed tracks please. What they said is exactly how it is, when I run a mission twice on a fixed track it already gets annoying. Now if I run the same missions multiple times I never get bored of the music, and it does add to the excitment of the game when you're in a pinch XP

Of course, that's my opinion. Memorable music = boring music


August 21st, 2012 at 4:44 am

Gonna admit the BGM isn't all that stellar (have to use my own custom playlists sometimes =x) aside from City BGM and the S-rank SFX =P

But yeah, I give them credit on trying something new, especially on an attempt on randomizing the BGM.


August 21st, 2012 at 4:48 am

Damn you guys have such shit taste. All of the music in PSO2 is pretty godlike, not even counting the boss music which absolutely shits on anything from past PS games.


August 21st, 2012 at 5:55 am

@Brightstar, if you could do that to Desert, it would be great. Desert doesn't seem to follow the rules of this system like other stages. The non-battle desert ignores the looping rules.


August 21st, 2012 at 5:56 am

@IAmSecretSpy The new classes are just classes. Think of them like alternative classes. Later on there's a subclass feature that we should know more about in October.


August 21st, 2012 at 8:10 am

What, people hating in Kobayashi and Tokoi? WHAT THE HELL ARE WRONG WITH YOU GUYS?! They're demi-gods of music!


August 21st, 2012 at 8:11 am

P.s. Jun Senoue is the God. *bows*


August 21st, 2012 at 8:20 am

I'm a little divided on the soundtrack overall, but I like what they've done with this system. Having reactionary music is what made PSO so unique and enjoyable, and had a rather negative effect when it was non-existent in PSU, even though PSU did have an excellent OST. Still, very interesting read for what goes on under the hood.


August 21st, 2012 at 9:59 am

I waved this article at a musician I chitchat with. the response I got was "…I haven't even heard the game's music and I can tell that's a crap system that would sound terrible.". /swt

yuki-chan/ololo> I can't tell if you're sucking up or easily pleased. the composers might be capable, but they're working with something that doesn't allow their talents to shine. it's not their fault, but upper management's. :P

Variable Mix is not an easy trope to get right. sega has, like many, not gotten it right.


August 21st, 2012 at 11:11 am

This is another example of how hard it is to make a random/procedural generator create content on par with the creativity of human beings. It can create more content of course with all the variations, but usually the quality of the masterpieces created by actual people overcomes it.

It's just like F.E.A.R. 3 random "scary" scenes. A different thing can happen every time you play said part of the game, but it will not scare you like those good moments from F.E.A.R. 2.


August 21st, 2012 at 12:02 pm

@-Z- I don't think his opinion matters if he didn't even take his time to listen to it. No offence to him, but to dismiss something right off the bat because he doesn't like the general idea of how it works is kind of … well, lame. Imagine he is a fruit connoisseur, one day you give him (what you think is) a very delicious apple he's never tried before, he looks at its surface and says "I haven't even eaten this, yet I can already tell this apple tastes terrible." Not quite right, no? Using "experience" as an excuse to criticize something he havesn't even tried…

And no, I'm not saying that the way PSO2 music is handled is perfect, but I'll take that over generic, orchestrated themes that always sound the same no matter how many times you visit the same area. Besides, there's nothing worse than hearing the same battle theme (or rather, 1st 30 seconds of it, cuz that's usually how long it takes to kill the all the enemies in a typical MMO) over and over again, you just end up turning the music off altogether.


August 21st, 2012 at 1:55 pm

*agrees with Plant*


August 21st, 2012 at 2:39 pm

I like the concept and think the implementation of SYMPATHY is well done. It does remind PSO, NiGHTS into the Dreams (perhaps the precursor of that genre) and Skies of Arcadia (especially the battle mode).

The music system made the game more interesting because it speaks to the player. That concept will soon be a standard to future MMO games.


August 21st, 2012 at 6:01 pm

Pretty much agree with Ololo, Plant and FinalZone.

The music in PSU was DULL and boring, like many of the

in-game areas in PSU became dull and boring, except for Haibaro Forest and some of the Seed monster populated areas. PSO2's dynamic music is excellently done IMO


August 21st, 2012 at 6:31 pm

I completely agree with Plant.

@bluejay: Raffon Meadow? That track was really dull to me, sometimes when playing PSU Raffon areas I would turn the music off due to that track being so boring.


August 21st, 2012 at 7:32 pm

see though you guys, the thing is… you're [i]wrong[/i] inasmuch as you don't have to hear something in action to understand it's flaws when you understand the field it's working in.

there is a difference between "can't judge a book by it's cover", which is what you're trying to call, and being able to judge something by understanding what makes it work. an automotive engineer looking at the blueprints for a car doesn't have to drive the finished product to see that the person who designed it screwed up. a researcher who's life's work is the study of snakes doesn't have to get bitten to know if a snake is venomous. a doctor need not suffer the same injuries as the patient to recognise something painful.

the flippant attitude with which you bandy about such out-of-hand dismissals is… kind of sad, honestly. suggests you've got absolutely zero clue about the subject and are simply desperate to defend it at any cost.

and further, I do wonder how many of those of you who are hating on PSU's music are doing so specifically because it's PSU, which I understand the PSO franchise fandom loathes for not being PSO1. I've seen people actually argue that stuff that was in PSU shouldn't be in PSO2 specifically because it was in PSU. that's… mindless blanket hate. and all fandoms for all things have SOME group that will do it.

I'll take actual music over randomly assembled clips any day. it's nice to actually know if the composer and perfomers have any clout, which you can't find out with something like sympathy. the only reason I don't have the music off in PSO2 at this point is that having none at all drives me up a wall, and I haven't a good replacement for it that won't end up obscuring things I do need to hear ingame.

and by the gods, since pre-ob I've gotten REALLY sick of the "pinch" track. again today I got the game throwing it at me when the party was alone in the area, in perfect condition, and curbstomping the monsters-of-the-moment. sympathy doesn't know how to gauge the action and adapt accordingly, from my experience ingame.


August 21st, 2012 at 7:55 pm

I agree entirely with Plant as well.

It's not a perfect system, and indeed, they should really add more unique sections designed to actually sound pleasing to the ear, but the sheer amount of variety that this system creates is nothing short of jaw-dropping.

Hell, the fact that the music is even COHERENT with so much swapping in and out is seriously noteworthy in and of itself…


August 21st, 2012 at 10:14 pm

the only thing that's good about this sympathy system is that it can make many combinations, but they're not implementing it well so the music that it's making to me at least, generally isn't good most of the time.

it's definitely still making music, and i suppose it's decently varied, but i'd rather listen to something i like, then something i'm eh whatever, to.


August 23rd, 2012 at 10:08 am

I like that the music changes according to your situation, thus never boring, and tells you of danger when it shifts.

I think the music feels "alive", y'now organic and sheeet.

And for those that complain, I get to hear the calm music a lot – For those that don't, you're not killing enough or fast enough lol :P

Each to their own tho…


August 23rd, 2012 at 12:56 pm

the problem is when it doesn't actually fit the situation. a full party curbstomping trash monsters in a few hits each should NOT trigger the "you're in a pinch!" track. that should be "hero" stuff, according to the system. so not only is it a crummy system it doesn't even do what it's meant to do. :P


August 23rd, 2012 at 1:20 pm

unless the "pinch" music was for whatever the game qualifies as "overwhelming numbers" regardless of how much trouble the party is having.

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