What is fm synthesis like on other synths (non yamaha dx's)

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Re: What is fm synthesis like on other synths (non yamaha dx

Post by GuyaGuy » Sun Apr 07, 2013 7:20 am

Jabberwalky wrote:This has probably been considered and rejected due to cost, but why has a knobby FM synth never been created in a compact synthesizer? The Dx200 is the only one springing to mind.
The DSI Evolver does knobby FM synthesis--in some ways more and in some ways less flexible than Yamahas. Apparently the Prophet 12 has some FM capabilities too--quite likely better for bell tones if they used cleaner oscillators. (The Evolver's oscillators have fairly obvious aliasing, which create ruder FM tones.)

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Re: What is fm synthesis like on other synths (non yamaha dx

Post by CZ Rider » Sun Apr 07, 2013 7:27 am

Tiger Jackson wrote:Why didn't the dx's have a filter?
The Synclavier II has CV outputs on the back for interfacing with external CV filters. The outputs could track at 1 volt per octave, and the CV's were part of the saved patch.
Pic of the many CV outputs on back of the Sync 2:
Image
There are dedicated buttons on the front panel to select the ammount and tracking. These could be used for any preset CV needed, but were designed with external analog filters in mind.
Image
The original Synclavier 2 is a strange digital FM synth that was around before MIDI. So many of the settings have very fine increments and not limited to the common MIDI 128 steps. While it was not "knobby", it did have a dedicated button per function. Tweaking the functions done by a single spring loaded knob, and had two real-time CV pedal inputs. The FM voices are made up of an additive type fixed oscillator with 32 harmonics. This can be used alone or FM'ed with a seperate sine via an envelope generator. Each voice can contain up to 4 parts called partials. Depending on how many voices, mine had 16 voices, a 4 partial voice would have a 4 note polyphony.
Here is a sample of a violin voice made up of 4 partials. In the sample I first play all 4 together, then each individually. I did set each voice with different LFO rates to fatten up the sound. Played at the end of the sample with effects like delay and chorus.

You can hear the oscillators "whine", kind of like a turbine engine sound when they go to lower frequencies. The Sync 2 has a full/large sound due to all the sound cards making the tones. For each set of 8 voices there are five large cards. One is a controller and the other 4 each contain 2 voices. So compared to a DX type synth, this would be more like a TX816, where you have seperate digital generators being mixed via analog audio together.
Here is another sample demo of the oscillator range. All done via the large front panel knob. I think it was playing a Cmin7 at first to show how there is no sidebands/artifacts when the oscillators go into the high range. A little polyphonic glide at the end. (Any sidebands/aliasing is from the MP3 conversion.)

It really does sound strange and has a sound all it's own. You can play the keyboard and transpose an entire sequence while it is playing for some really crazy fun. Sounds like tape slowing down.
Here is a sample of transposing a playing sequence.

A real advanced FM synth in it's day. The DX took FM a step further, but the Sync 2 was out years before Yamaha licenced FM from Stanford University.


The Casio Phase Distortion synths had an interesting way of getting around that license. The Yamaha is actually Phase Modulation, and Casio's take was to read the phase of a sine wave faster and slower. To distort the sine wave into shapes by clocking the reading of the 360 deg. phase at different rates. It does basically the same thing, just a different way of getting there.
I always like the Casio method, and is was more of a subtractive approach. Had three 8 part envelopes, first one for pitch the DCO. Next one for the wave shaper or phase distorter called DCW, and another for amplitude DCA. The numbers assigned to the envelops were a bit strange. A zero time was the longest and 99 the shortest. I found it best to think of these numbers as angles where zero equaled a 1 deg angle, and 99 equaled a 89 deg. angle. Imagining drawing the angles that way gave a better visual of what was going on with the envelopes. There is also anassignable sustain and end point, making these 8 part envelopes the strength of the CZ.
The battery operated model CZ-101, 1000, 230s always sounded different to my ears. Must be the 9 volt rails those models have limiting the headroom, creating a distortion. The 15 volt rail models CZ-1,3000,5000, seem to be lacking that same grit. They seem to just sound clean and loose something.
My favorite patch on the CZ-101 is the guitar one. As the tone settles back to the original sine wave, almost sounds like feedback. Very expressive and a fun sound to play.
Casio CZ-101 lead guitar sound. (Moog modular bass and Simmons drum backing)


The CZ-101/1000 were the originals, with the other models following later. The CZ's popularity was due to being the first affordable MIDI keyboard many owned. Casio later followed up with the iPD, or Interactive Phase Distortion line including the VZ-1, VZ10M,VZ8 and the iPD synthesizer guitar models like the PG-380. The iPD was a little more like the DX series with 8 operators, and sounded different from the CZ series. Casio left the professional synthesizer market after these. Too bad, really!

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Re: What is fm synthesis like on other synths (non yamaha dx

Post by vinyl_junkie » Sun Apr 07, 2013 11:58 am

There have been knobby DX's... Well kind of

The Access DX-7 Programmer

Image

I've always loved FM synths mainly cos they were my first synth. Badly need a DX-7 for no other reason than because more is more and it looks damn good lol

I actually like all the aliasing and c**p the cheap DX's make like the 100 and use it to good effect

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Re: What is fm synthesis like on other synths (non yamaha dx

Post by Jabberwalky » Sun Apr 07, 2013 1:20 pm

Holy s**t! Ok, well, from a cost standpoint I can see why it isn't something common. However it could possibly be something more similar to the 4-op Dx synths with about half as many knobs as that programmer.

I'm also a big fan of the crunchier FM synths with the bad DACs. Dx9, Dx21, Dx7mk1, CZ1000. Just adds something unique and scathing to any sound.

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Re: What is fm synthesis like on other synths (non yamaha dx

Post by 8bit9bot » Sun Apr 07, 2013 2:41 pm

@CZrider - thanks for posting those synclav demos... except... now i have to cry cuz i will never get a chance to use one in my music x.x

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Re: What is fm synthesis like on other synths (non yamaha dx

Post by CZ Rider » Sun Apr 07, 2013 5:03 pm

So how would a knobby interface actually work on an early DX type synth?
On the CZ series, depending on the model, there is very little real-time control of parameters via MIDI. Even with a knob per function controller, you would need to keep sending the entire patch to make changes. The front panel works the same way and it stutters if you hold a note to listen and make changes. This was the early days of both MIDI and digital synths, so there was no real standard way of doing parameter changes inside the synth engine. For those early Casio's the whole program packet was sent, making any real-time changes slow. The Casio could not accept just one parameter change inside the CZ engine, but needed the entire patch sent. Guessing the DX's were different this way. Casio always had a wonky MIDI send/receive hand shake going on, so any MIDI editing needed both MIDI in/out to be connected. Today they would do it differently.

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Re: What is fm synthesis like on other synths (non yamaha dx

Post by Bitexion » Sun Apr 07, 2013 5:51 pm

I doubt it would work very well for its purpose. Knobby analog synths don't require the pinpoint frequency accuracy that a DX synth does to track pitch over many octaves without losing the exact frequency ratio (and thus sounding dissonant). And DX synths don't have or need a lowpass filter either. And there's such a myriad of important parameters that the control surface would be a total mess.

Big filter cutoff knobs are for realtime direct control. You don't do much of that on a DX synth, except for the modwheel.

Wouldn't make much sense with operator pitch knobs either, since you'd just be fine-tuning it forever to get the exact decimals rather than just click a button and get it right there.

It's sort of like wanting screws on a digital watch to set the time instead of just click, jump to next digit, click. Or replacing the keypad on a calculator with data-entry knobs. *shudder*

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Re: What is fm synthesis like on other synths (non yamaha dx

Post by CS_TBL » Sun Apr 07, 2013 6:15 pm

CZ Rider wrote:So how would a knobby interface actually work on an early DX type synth?
Perhaps the answer could be compared to how I use FM8; using a mouse! I don't use a controller at all, there's just too many parameters to find a decent controller for, not to mention having dynamic things like segment envelopes. The thing with FM is that most tweaks (especially in the FM algo: output levels, feedback loops) are very subtle. I really don't need a hardware knob for that when I have a mouse moving area of 20..30 cm for that parameter. I also don't need to tweak multiple things at the same time, nor do I need to switch between parameters within a split second.

If I could make an analogy: editing FM is like painting fine and realistic art, like being Rembrandt. Lots of careful details per square inch for which you really don't need multiple things at once. Having a few knobs to do quick tweaks would - to me - feel more like speed painting modern art. Now, of course I haven't used FM8 with a controller (apart from an hour with my Behringer BCR2000, after which I concluded that even 32 knobs wouldn't work for me), but my gosh; a controller for FM8, that would be a big boat anchor of a machine, with a price to match.

So, assuming that my FM8 thingies have so far turned out to be pleasant thingies, then obviously I'd be fine with the mouse being the only parameter editing controller I have. At the same time it's perhaps a bit hard to compare a synth-like surface with a computer screen (lotsa parameters in a small space, because the software doesn't assume there are human fingers touching these virtual buttons/sliders). But alas, what can you do..
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Re: What is fm synthesis like on other synths (non yamaha dx

Post by Jabberwalky » Sun Apr 07, 2013 6:17 pm

I'm thinking of it in a Meeblip sense, where you have both digital switches and analog knobs (which could be modulated VIA CV)

No filter knob. Just give it 4 volume knobs, 1 per Operator. That would be simple, with pretty much the same effect.

Knobs or sliders for the envelopes...those work almost exactly the same as many other synths. I hate pluging in envelope values via a data slider.

Now the pitch knobs could have a course, and either a detented fine tune, or one with latching values.

A feedback knob would be simple and could possibly be more flexible.

All the other parameters like, LFO modulation, rate, etc are taken from the analog domain and would be the same.

I think something like that would be an excellent and fun instrument. It wouldn't be a classic FM programmers synth like the oldies. It'd be more of a down and dirty, gritty and direct approach for live tweaking. This is all theoretical, so I might whip something up in Synthedit to see how useful it is in a song writing session.
Last edited by Jabberwalky on Sun Apr 07, 2013 6:23 pm, edited 1 time in total.

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Re: What is fm synthesis like on other synths (non yamaha dx

Post by CS_TBL » Sun Apr 07, 2013 6:22 pm

Bitexion wrote:And DX synths don't have or need a lowpass filter either.
That's actually a myth being kept alive by far more insane FM fanboys than I am.. ^^

There's certainly a reason to use a filter, but it's all about being subtle. You won't see me doing traditional reso/filter sweeps for "wow"-kinda basses. But "acoustic" pianos do require a filter (24dB if possible), and brass instruments may profit from filters too. Also, keep in mind there's hpf too, you don't easily do that (or not at all) with alternative FM parameters.

I'll assure you that I've put a considerable amount of time in the filter when making this piano.
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Re: What is fm synthesis like on other synths (non yamaha dx

Post by tekkentool » Sun Apr 07, 2013 6:56 pm

CS_TBL wrote: There's certainly a reason to use a filter, but it's all about being subtle. You won't see me doing traditional reso/filter sweeps for "wow"-kinda basses.
oops :oops:

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Re: What is fm synthesis like on other synths (non yamaha dx

Post by Bitexion » Sun Apr 07, 2013 7:05 pm

I have sometimes wished for a lowpass filter to dial out some of that hissy aliasing on DX7 patches, sure. Just..using different waveforms and multimode filters on a DX7 dilutes the purity of the concept to me.

I come from the computer era of SID chips and 8502 assembly programming, I even thought it was cheating to load up a "music program" on the C64 instead of coding the music on the chip directly to make SID music. I had to learn how to work within very tight memory limits. So I kind of kept the same view on my DX7S programming. "Keepin it real" so to speak. It's a silly obsession, but that's me, I guess..
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Re: What is fm synthesis like on other synths (non yamaha dx

Post by 8bit9bot » Sun Apr 07, 2013 7:05 pm

@CS_TBL amazing piano! why dont DX synths have filters? i think the primary reason is cutting cost - but yeah also LPF is the most common filter type - dont need that on a DX... but clearly HPF sounds quite awesome in your example

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Re: What is fm synthesis like on other synths (non yamaha dx

Post by CS_TBL » Sun Apr 07, 2013 7:56 pm

Oh there's no HPF in that piano, just an LPF with a weeeeeeeee bit resonance, but the Fc-peak isn't even visible from a distance.. :)

Filters have their place in FM, just more subtle. In subtractive synths, the filter is one of the most important sound shaping elements (next to waveforms, ringmod, sync, pulsewidth), while in FM-synths the basis shape is usually done with operators. But even then, a filter has its role.

Look at it from a different angle: In FM the 'brightness' (the FM level) grows harmonics in a bi-directional way, while filters wipe harmonics top-down (one-directional). A filter is a more radical way to cut away harmonics, and sometimes it's this radical style you want.
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Re: What is fm synthesis like on other synths (non yamaha dx

Post by vinyl_junkie » Sun Apr 07, 2013 8:24 pm

Jabberwalky wrote: I'm also a big fan of the crunchier FM synths with the bad DACs. Dx9, Dx21, Dx7mk1, CZ1000. Just adds something unique and scathing to any sound.
Yea I love it.. All that snap+crackle&pop :-D


It still amazes me what you can get out of these very limited 4OP synths


Another nice moody evolving bell like tone

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