1.333 FM Ratio

randy909 · 2023-01-06T01:42:41.363Z

I’ve been messing with setting the operator offset to .333 on my DN and really enjoying the result, so much so that I’m wondering why 1.333 is not in the list of values for operators C or A. It sounds dissonant but less so than 1.250 does to my ears. This thread has some info on this topic but it seems to apply to ratios more like 1:3 than 1:1.333. Is there a relationship?

bibenu · 2023-01-06T10:58:41.228Z

This might help -> Frequency and Ring Modulation calculator (FM & RM) - Michael Norris, Composer

Example: you add in carrrier of 256 (C I think) and a modulator of 256*1.333, with low modulation, then it adds a 4th below (F) and 9th above (D)

randy909 · 2023-01-06T22:03:22.008Z

Very helpful thank you!

I think what I’m preferring about this ratio is that several of the sidebands are harmonics. BUT the first sideband of 1:1.250 is a fifth whereas with 1:1.333 the first harmonic is an augmented 6th? A to F# whatever that is. So if you have a lower modulation set the 1:1.250 ratio probably sounds a lot more musical? Eh, I just tried it and 1:1.333 sounds smoother to me. Tried some chords to see if one was superior for that but they both sound terrible.

I conclude that 1.333 is a great ratio! I can share the numbers I came up with (the list of sideband frequencies) if anyone is interested.

LyingDalai · 2023-01-06T23:34:46.237Z

Note that you can choose a ratio of 1.250 then shift it with the ratio offset (of +.083 to reach your favorite ratio) on SYN1 Page 2.

RustyRoses · 2023-01-07T00:05:59.399Z

This is the kinda technical nerd talk I come for

plragde · 2023-01-07T00:07:41.444Z

That 1.333 = 1.250 + 0.083?

randy909 · 2023-01-07T05:32:55.581Z

I’ll take that as permission . Here are my nerd notes.

1.25 ratio, carrier at 110, modulator at 137.5
Frequency (Hz) Note
27 A
110 A2 is fundamental
164 E (5th above)
247 B
301 D
384 G
438 A (~440)
521 C
575 D
658 E (~660)
712 F
795 G
849 G#
932 Bb
986 B (~990)
1069 C
1123 C# (~1100)

1.33 ratio, carrier at 110, modulator at 146.63
Frequency (Hz) Note name
36 D
110 A2 is fundamental
182 F#
256 C
328 E (~330)
402 G
474 Bb
548 C# (~550)
620 Eb
694 F
766 G (~770)
840 G#
912 Bb
986 B (~990)
1058 C
1132 C# (~1100)

As you can see (pushes up glasses) there are more harmonics for 1:1.333. I just noticed that they are all odd harmonics so maybe that wave is more square-ish than the other where the first two harmonics are even? I wish ableton had a scope plugin. Anyone know of a good free scope plugin for ableton on mac?

LyingDalai · 2023-01-07T08:11:00.878Z

randy909:

scope

PC software oscilloscope Other Gear

Hi all! I should like to watch my eurorack signal using an oscilloscope on PC. I never use computer to make music, so I don’t have a DAW and other software. I just want to plug my eurorack output into PC’s audio input and watch graphical representation of the signal, with frequency and amplitude. What’s the best software? Any advice?