difference between ym2149 and AY-3-8910?

By syn

Prophet (2106)

syn's picture

12-04-2011, 22:07

From the information that I gather from wikipedia and such, the ym2149 (as used in for example atari ST) and the AY-3-8910 (msx PSG) are almost identical.

But when I listen to music on youtube of atari st mods/demos, I feel the ym2149 sound is different than psg.. maybe better (though this may be a matter of taste). I was just wondering, is it just difference in chip or maybe faster processor resulting in better control over the chip itself (from trackers or whatever)?

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Enlighted (6890)

ARTRAG's picture

12-04-2011, 22:17

as you said all the difference is on how the Atari ST processor controls the chip
consider that it has programmable timers that allows the YM to be addressed at 21KHz
allowing in this way pcm audio mixed to the standard tones

look at the YM format here for details

apart this the two chips have almost the same features
only envelops differ slightly but at user level there is no difference

By wouter_

Champion (492)

wouter_'s picture

12-04-2011, 22:33

Like ARTAG already said, the envelope differs slightly: AY8910 has 16 envelope levels (same levels as can be chosen by the volume registers), while the YM2419 has 15 extra in-between envelope levels.

Another lesser known difference is that on YM2419 you can read back a register value just as you have written it. While on AY8910 unused bits (e.g. upper 4 bits of register 1, 3, 5) always read back as '0' (even if you had earlier written '1' to them). But of course this doesn't make any difference in the generated sound.

By syn

Prophet (2106)

syn's picture

14-04-2011, 01:57

thanks for the link artrag, it was very informative. I already noticed the higher quality drums in a lot of tracks, so now I know are digidrums. And the sidvoice and syncbuzzer would explain the nicer melodic sounds.

The question is, would turbo r or 7mhz upgraded msx be fast enough for something like this? (I am no programmer so I have no clue how to implement everything)


Enlighted (6890)

ARTRAG's picture

14-04-2011, 08:19

probably yes, but the answer depends on the sampling rates to be emulated
For sure, with higher rates you cannot implement the code on the line interrupt
and you have to do cycle accurate code (for a 7MHz z80) or poll the RTC in test mode

By MäSäXi

Paragon (1884)

MäSäXi's picture

14-04-2011, 18:41

Maybe this answer will tell you something:

I once bought a lot of Your Sinclairs for just mere shipping costs, and when I read issues I didn´t had, I found out something which surprised me. One Spectrum fan told that he got new Atari ST and was really irritated as Atari ST games´ music sounded just the same what his 128K Speccy gave...... there was something more, but I cannot remember any better.

By Gradius2

Hero (652)

Gradius2's picture

08-07-2014, 02:18


Sorry for the bump, I was looking for YM2149 and found this topic.

YM2149 is superior to PSG, I remember that since 1986 and 1987 when I heared Atari ST personally, it really sound better than PSG, no question!

By AxelStone

Prophet (3176)

AxelStone's picture

08-07-2014, 08:29

It's strange but I allways thinked that PSG is better, I prefer MSX musics than Atari ST musics Shocked! . Perhaps the japanesse compositors are vey used to PSG but I feel that Vampire Killer has better sound that any Atari ST game.

By Manuel

Ascended (19058)

Manuel's picture

08-07-2014, 12:30

I don't think you can hear the difference between them as they're 100% equivalent for how they are used.

By Grauw

Ascended (10635)

Grauw's picture

08-07-2014, 15:22

The PSG embedded in the Yamaha MSX Engines is the YM2149, so the YM2149 is also used in many MSX computers.

I think difference in sound quality between MSX and Atari ST is indeed probably due to higher resolution timers.

By hit9918

Prophet (2926)

hit9918's picture

09-07-2014, 06:43

It does not always need to be the cpu doing work of "kilohertz digi" rate.
On the "monitor rate effects" side, going 2x or 4x the usual 50 / 60hz too could do things.

Drums were mentioned, they go with flipping registers at monitor rate, a candidate.
The player called at higher rate, needs more cpu, a candidate for TurboR games.