Learning ACE.. FM

[GruvSyco]

Hello,

I am trying to get a feel for programming ACE (finally after owning it for 6 months) and have been stepping through the manual. I was a little stuck on the LFO1 section where it talks about FM and I think I got it but not sure. Is the following patch an example of basic FM on ACE?

http://dl.dropbox.com/u/766311/basic_fm.h2p

I couldn't figure out how to do the self modulation that it talks about... assuming you are routing the output of LFO1 back to itself. But the patch above kind of reminds me a bit of my early experiences of tweaking the DX synths (in that you can get some really shrill tones).

I've been pretty thrilled with just patch tweaking so far but learning to program ACE is bring that to a whole new level.

[xh3rv]

Is the following patch an example of basic FM on ACE?

Yes - LFO1's phase mod input is the path to classic FM sounds.

It's actually a little more than 'basic' FM as you're feeding a square wave 'modulator' into the 'carrier'. The rule with FM is the modulator creates mirrored sideband frequencies based on the relationship between it's harmonics and the carrier's harmonics - this is sort of sane and calculable if both are sine waves, since only fundamental frequencies are involved.

A square wave has a lot of harmonics, so a lot of sidebands are generated.

I believe classic FM was pretty much about sine waves. The easiest way to stick with sine waves in ACE is to use LFO2, but it's also worth noting the filters can give a very sine-y wave when self-oscillating. Also OSC1's alternate waveforms are a little tamer than saws or squares for FM uses.

ACE being ACE though, there's real power in feeding exotic things into the phase mod of LFO1 It's often a tricky balance but worlds of possibilities exist.

Worth noting that the depth of LFO1's phase mod knob affects the amplitude of FM sidebands - putting some kind of envelope on what gets fed in here with e.g. one of the multipliers or LFO2's depth mod (conveniently already set to adsr2) is a useful technique. As filter envelopes are to subtractive synthesis, envelopes on the modulator are to FM.

(Oh, also I think the self modulation you mention is feeding the output of LFO1 back into the LFO1 phase mod knob)

There is plenty of (more) helpful stuff on the net for explaining FM, worth searching YouTube and Vimeo even as well

[GruvSyco]

Wow, thanks for the in depth reply. I knew the square wave was not traditional FM, I just really wanted to make sure the routing was right.

The phase knob usually determines phase position. This value can be modulated
by any signal. For instance, connecting another oscillator gives you classic FM
sounds (which illustrates that those synths were actually based on phase
modulation - "FM" is a misnomer). Of course this modulation source could be LFO
1 itself ("FM feedback"), which results in a much brighter waveform similar to a
sawtooth.

I was playing around trying to get this to work with a minimum of routings, once just trying to route the output of LFO1 back into the Phase Mod input of LFO1 and nothing seemed to work. I went through the mixer once and got what appeared to be some FM but with the initial wave of VCO1 as well. I had gotten frustrated with this that I went on to the next section of the manual about S&H with LFO1 and played with that for a while since I was actually able to make a noise. I went back to the FM part and just tried putting the cable in different places until I got what I expected it to sound like when adjusting oscillator pitch. Thats why I posted the question like I had it, it wasn't really a conscious choosing of what I had done and wanted to make sure I had the routings right for FM.

Anyways, I played a bit afterwards, incorporating the sample and hold tricks just to see what I could do and came up with this. http://dl.dropbox.com/u/766311/basic%20fm%20noise.h2p. Lowering the gain and cutoff yield cool laser blast like sounds while playing with resonance changes the character of the explosion-like sound. Pretty cool, I thought.

Then I was wondering what would happen if I tried modulating the other three oscillators in the same manner and got this fun patch. http://dl.dropbox.com/u/766311/fm%20sprungpiano.h2p. I haven't listened to it this morning yet but last night at 2am I thought it sounded kind of like a cross between a harpsichord and a music box piano.

I don't know enough yet to intentionally do any of this but, I'm assuming this will come with playing around and experimenting and seeing exactly what happens when you move cables and such.

[xh3rv]

I don't know enough yet to intentionally do any of this but, I'm assuming this will come with playing around and experimenting and seeing exactly what happens when you move cables and such.

Ya that's pretty much where I'm at too - I want to say something about how ACE is a chess match compared to a lot of soft synth's checkers ... it's a chess match where you can check-mate yourself every once in a while

[GruvSyco]

lol

[Gonga]

Bookmarked. Thanks for this thread.