iYM2151

iYM2151

by wolf_ on 21-05-2012, 12:24
Обсуждение: MSX Related
Теги: CX5m, iPad, YM2151
Языки:

The YM2151 chip was used in several products, the Yamaha CX5m (often seen as a music computer first, and an MSX second), the SFG-01 and SFG-05 expansions, several Arcade machines and a number of Yamaha DX synthesizers. For almost all MSX users, this chip (in whatever shape) never gained the popularity which the FM-PAC had, and frankly: if you listen to music made by Micro Cabin, Falcom and Compile, you may wonder what the point of this YM2151 was anyway. One might argue that music from Xak - The Tower of Gazzel blows any conventional YM2151 output away, although it must be noted that Micro Cabin was far from conventional as far as their music was concerned. So, to compare regular usage of this YM2151 with the best Japan had to offer in the 90's would be a bit unfair.

So, back to the YM2151; it has some nice bits to offer, to name some: 8 channels, 4 operators, stereo. Owners of an iPad can now have a go at all this in form of iYM2151, developed by DETUNE Ltd., who already made an App based on the famous Korg MS20. With this new App, users can create sounds and music on their iPad. For a quick impression of how iYM2151 works in practice, there is a whole slew of demonstration videos available here. For ¥3,000 (roughly €30), this App is yours.

Relevant link: iYM2151 at iTunes

Комментарии (20)

By Jorito

Mr. Ambassadors (1761)

Аватар пользователя Jorito

21-05-2012, 19:21

Especially the second demo song reminds me a lot of the Philips Music Module songs somehow.

By Manuel

Ascended (15682)

Аватар пользователя Manuel

21-05-2012, 21:07

Imagine with Microcabin would have done with the YM2151!

By dvik

Prophet (2200)

Аватар пользователя dvik

21-05-2012, 23:00

Looks very nice Smile That keyboard would be something for MSX.emu to include to make full use of the CX5M machine in the emulator.

By Gradius2

Hero (574)

Аватар пользователя Gradius2

22-05-2012, 05:40

First time I hear this thing, the bass is nice and the stereo too, the rest not anymore.

By shaiwa

Champion (369)

Аватар пользователя shaiwa

22-05-2012, 08:32

Nice, recently found a SFG-01, need a to nomal slot converter soon when hearing this ...

By wolf_

Ambassador_ (9767)

Аватар пользователя wolf_

22-05-2012, 13:56

You may be surprised by the fact that extra operators and algorithms, the specific way they're implemented in the YM2151 (but also in e.g. the Moonsound), offer relatively only few handy new bits for a composer. Added value from extra operators will have value if each operator has fine tune and when there are multiple feedbacks in an algo. Extra waveforms, and complex signal flow (such as [4]->[3]->[2]->[1]), usually tend to complicate waveforms into a complex tone that doesn't add much compared to simple 2-op models like in the FM-PAC. Again, listen to Micro Cabin..

The best way to make an enhance FM-chip would've been to add polyphony (18 2-op FM channels is far more practical than 9 4-op channels), and add a few DSP effects such as chorus, delay and reverb and offer send parameters per polyphonic channel. Technically this would really not be very complex, the implementation techniques for such effects are rather simple in fact.

By DamageX

Master (214)

Аватар пользователя DamageX

23-05-2012, 10:04

wolf_ I am surprised you would write that, because for me there is a clear difference in sound between 2-op MSX/SMS/Adlib compared to tracks from 4-op chips like in X68000/Genesis. Although I can believe that stacking all four ops wouldn`t be very useful (my Yamaha DX synth doesn`t even include that algorithm).

When you mention 18 FM channels are you thinking of MSX-AUDIO + FM-PAC or more like OPL3? Don`t know if I`ve ever heard anything that utilized all 18 channels or close to it.

By anonymous

incognito ergo sum (109)

Аватар пользователя anonymous

23-05-2012, 13:44

With these 18 channels I wasn't referring to anything specific. FM is just FM, whether it's a Yamaha synth, a VST or an FM-PAC.

Of course there is a difference between 2-op and 4-op, the question is whether this difference is relevant and whether it's relevant enough to offer a polyphonic channel for that. With sine operators (like a Yamaha DX7), I could see a number of applications for 3- and 4-op serial algorithms (e.g. 4->3->2->1), but since this YM2151 and the Moonsound have operator waveforms, the advantage is less relevant- though not completely zero. In my own FM8 videos, many sounds are in fact composites of 2-op algorithms. So even when I use all 6 operators, then it'd often still be 2-op + 2-op + 2-op.

So, is there a difference between 2x 2-op FM and 1x 4-op FM if this is the algo: (4->3->output, [FB]>2->1->output, known for being used as the DX/EPiano). Suredo!

With two 2-op channels you gain the following:
- a feedback per operator stack, rather than only one
- detuning per operator stack
- stereo panning per operator stack

Next to all that: basic sounds are very practical.. be it sawtooths, blocks, it doesn't matter. There's more often than not barely any point in extremely complex sounds. They may sound funny 'n cool in the voice editor, but in a musical context they're often not needed - a perfect analogy with weird preset sounds in synthesizers that sound nice in the shop but are very impractical in a musical context.

By AuroraMSX

Paragon (1901)

Аватар пользователя AuroraMSX

23-05-2012, 17:35

ok, now I really need to buy an iPad oO

By WORP3

Paladin (804)

Аватар пользователя WORP3

23-05-2012, 19:47

Is looking nice Wink
The most of you will recognized this song:

http://www.youtube.com/watch?v=oX-INdxV-So&feature=related

By wolf_

Ambassador_ (9767)

Аватар пользователя wolf_

23-05-2012, 20:37

Ah, so it uses full channels for its drums.. in this case reducing melodic channels to five. No matter how contradicting it may be, but I think the FM-PAC and PSG together outrun this YM2151.. Smile

By janghang

Expert (115)

Аватар пользователя janghang

24-05-2012, 10:20

anybody knows why there has not been any game or demo which supports YM2151 (CX5M/SFG01,05) in MSX? Is this due to some technical problem? For instance, do playing YM2151 music require too much CPU or memory resource to run normal game or graphics demo in CX5M?

By wolf_

Ambassador_ (9767)

Аватар пользователя wolf_

24-05-2012, 11:23

Probably because it's not very mainstream. Commercial game companies aim at the biggest market share, and demo makers aim at the biggest audience. It can't be a technical issue: if an MSX can play 24 Moonsound channels and 18 FM channels together (although it hasn't been done yet), then operating 8 FM channels of the YM2151 shouldn't be any trouble.

By msxholder

Champion (336)

Аватар пользователя msxholder

24-05-2012, 22:20

There is an Demo Tape maybe I 'm willing to take it with me to Hoorn this Saturday

By erwinmusik

Master (140)

Аватар пользователя erwinmusik

27-05-2012, 13:04

Amazing! Now it´s time for me to by an iPad.
That´s the funniest reason Smile Smile Smile

Thanks for these information, I never searched the Appstore for those stuff, Z80 emulators, basic emulators....I never came up with the idea to search 2151

By syn

Paragon (1920)

Аватар пользователя syn

29-05-2012, 01:17

wolf_ wrote:

Ah, so it uses full channels for its drums.. in this case reducing melodic channels to five. No matter how contradicting it may be, but I think the FM-PAC and PSG together outrun this YM2151.. Smile

as much as I love msx music I dissagree. Purely judging from youtube (since I dont have a real x68000) I feel in general ym2151 sounds "fuller" compared to msx music.

for example the sharp x68000 had a ym2151
http://www.youtube.com/watch?v=OyfcUaszGmU&feature=related xak on x68000.. this also answers manuels question what microcabin could have done with a ym2151
http://www.youtube.com/watch?v=uhPSonNiMJk YsIII
http://www.youtube.com/watch?v=3cJtaN5hHtQ&feature=related Genocide 2, I really love this soundtrack :D

okay ofcourse the x68k also has 1 channel pcm, probably used for the drums so you should ignore the drums if you want to compare.

and besides, I would say stereo alone is a big step forward/improvement

By popolon33

Expert (84)

Аватар пользователя popolon33

29-05-2012, 08:38

wolf_ wrote:

In my own FM8 videos, many sounds are in fact composites of 2-op algorithms. So even when I use all 6 operators, then it'd often still be 2-op + 2-op + 2-op.
With two 2-op channels you gain the following:
- a feedback per operator stack, rather than only one

Sorry to say that but this is kind of "additive" synthesis, not the way FM should be used Wink
that's why there is no such algo in most of the FM-Chips/synths (FM8 excluded...)

wolf_ wrote:

It can't be a technical issue: if an MSX can play 24 Moonsound channels and 18 FM channels together (although it hasn't been done yet), then operating 8 FM channels of the YM2151 shouldn't be any trouble.

Sure it's not a problem ^^
http://www.youtube.com/watch?v=wX1u7a_s4mg

By wolf_

Ambassador_ (9767)

Аватар пользователя wolf_

29-05-2012, 11:44

popolon33 wrote:

Sorry to say that but this is kind of "additive" synthesis, not the way FM should be used Wink

There's no law that dictates how complex FM should be in order to be labelled 'FM'. 2-op FM is FM. Heck, one operator with feedback is FM already, just as having a very fast vibrato connected to an oscillator. There's no point in going complex, only for sake of being complex, the only thing that counts is the result. Now, a serial algo of 3 or 4 operators has its uses if your operators only have sines, like in the DX7. Because with that, you can make modulator envelopes making the sound go from "complex to complex", rather than "complex to sine". But as soon as an operator has operator waveforms (FM-PAC, Moonsound, YM2151), having a non-sine as carrier already means an envelope from "complex to complex". Anyway, all this is pure academic blah. Imagination and ears, that's what you need to create FM sounds, not what the books and the specifications say.

Btw:
fb[1]->[2]->out
[3]->[4]->out
is a rather standard algo in FM synths (the DX7 ePiano). 'Additive' as you call it, although true additive would refer to Fourier synthesis, which is not the case here. So, if that's already standard:
fb[1]->[2]->out
[3]->[4]->out
[5]->[6]->out
shouldn't be that alien, no?

As for which algos those synths had or didn't have: these algos often had no point, other than being a variation to the other algos. The number of people who could create decent FM sounds out of a DX7 was frustratingly low - hence, you hear the same presets being used on all these albums from the 80'. With such little user feedback for Yamaha, they probably wouldn't know what algos to make anyway. And why would users want a 3x 2-op structure anyway.. for pads? Go for a Jupiter, Synthex or Prophet, not a Yamaha DX.. or heck, a DX connected to a chorus effect. The Yamaha SY77 would later have custom FM routing, multiple feedbacks, and - more importantly - filters. Especially the latter was like finally giving in to the fact that at some point you're going to need some filters - FM synths omitted those for years.

As for stereo: yes and no. Hard-panning with a low number of polyphony is tricky business as it creates great holes in the stereo image. If you pan a sound full-left, then in the center and right you have nothing, this creates this hole. Of course you could pan another sound full-right to balance the left sound, but you get the same issue again. In a way you are making the stereo image somewhat weak if autonomic voices are hard-panned. Of course you can create a double voice; one instrument with a left sound and a (different) right sound, but that'll cost you two channels from a chips that hasn't got much of those anyway. In the Moonsound it works a bit better because you can have up to 18 channels (2-op), so there's a lot more space to counter-balance hard-panned instruments. The best way to create a stereo image would've been by adding DSP effects (reverb, stereo delay, chorus etc.), which really aren't that hard to make - it costs you some memory though, to store all the audio from the delay lines.

By popolon33

Expert (84)

Аватар пользователя popolon33

30-05-2012, 08:35

I understand your point "as a composer"
IMHO, sound output with algo 3 OP is richest than sound output with algo 2*2 OP, whatever you would do to enhance it.

Wolf_ wrote:

Ah, so it uses full channels for its drums.. in this case reducing melodic channels to five. No matter how contradicting it may be, but I think the FM-PAC and PSG together outrun this YM2151.. Smile

nope, you can use all channels as you like with OPM.
that's why i think that SFG series (YM2151 8*4OP) was the best chip for MSX, even if it lacks ADPCM.

By Manuel

Ascended (15682)

Аватар пользователя Manuel

30-05-2012, 10:28

X68000 looks like a very nicely specced machine. Kind of like the Japanese Amiga Tongue Great thing, it seems.