DSN-12 Tutorial: Chapter 7: The FM Sound of Genesis

It would seem logical that after discussing the NES, I would want to write about the SNES next. Well there is an issue with that. The Super Nintendo used a wavetable synthesis method, meaning the waveforms were drawn manually. It is quite the opposite of the subtractive synthesis on our DSN, in fact it is a method called additive synthesis. What I've seen from the Korg M01D for 3DS sounds very SNESy to me, but I think that app only has presets and no wave shaping utility, so there are limitations. The Sega Genesis also used additive synthesis, but in a completely different way, and although we can't get all the same sounds on DSN, we can get close. I haven't found a whole lot of information about recreating the Genesis sound, which is kind of sad because it was so different in it's approach and sounded exactly as grungy as I like to remember the 90s.

FM synthesis refers to Frequency Modulation. The name may make you think of FM radio, which also means frequency modulation, it's just used in a different way. Let's not talk about FM radio, because I will just end up getting too in the weeds here, and I just wanna make some noise.

The technique behind FM synthesis was first discovered on analog synthesizers, but the instability of analog components did not yield consistent results. It wasn't until the 1980s that FM synthesis got to shine in the new fancy digital synthesizers. DSN looks like an analog synth, but it has the pitch stability of a digital synth, because it is a digital signal. FM synthesis involves modulating the (you guessed it) frequency of a wave with a carrier wave. Frequency refers to how frequent the waves are, so more waves is higher frequency. If you've played around with the keyboard on DSN and looked at the oscope, you may have noticed that as the pitch changes, the frequency changes at the same rate, because pitch and frequency are kind of the same thing. This sounds kind of easy actually, just use the patch page! Let's do this.

Start a [NEW] song then navigate over to PATCH for Tr01. Just connect VCO2 to VCO1 PITCH IN. We simply go from this:

Now that looks like a mess. I can see why people claim the Genesis had inferior sound. But wait! It was not inferior, it was just different! Let's tinker with the PITCH IN knob on PATCH and the VCO2 PITCH knob on SYNTH to hear all sorts of different sounds. What a range. Change both VCOs to the triangle wave (full left) and you have something that sounds in the range of a Sega type sound. Here is another video using the DS-10, or the DSN's predecessor. I also really like both as square waves, it really reminds me of Sierra adventure games from the early 90s.

Now a few things to note. First of all, although we can make a wide range of complex sounds with this technique, a lot of them sound messy. This is a problem that musicians and programmers in the US did not like about FM. Many relied on presets, and not all great ones. This only gave people more reason to think that Sega sounded bad. The Yamaha DX7 was everywhere in 80s pop music, but many musicians relied on presets there as well.

Now, I know that there were more operator waves on the carrier waves in both the Genesis and the DX7, whereas we are only working with 2 waves, making it much simpler, since we only have two knobs to change around. If we had four knobs to change, and changing one makes the others act differently, you could get lost for hours in that situation. The FM synth on the OP-1 synthesizer is great for that, actually. If you are looking to drop some serious cash on a synth, I recommend that one.

Back to DSN. so we have our two knobs on two different pages, but it gets old quick switching back and forth between the two. Let's use Kaoss. From SYNTH, click on KAOSS. Go to 3. Click the words on the bottom left, like so:

You will see KAOSS X and CUTOFF are highlighted. Click on VCO2 PITCH. Click on KAOSS Y and then VCO1P MOD. Click YES on the bottom right. Now we control those two knobs with our Kaoss 3 pad. X is the horizontal (left is lowest, right is highest) and Y is the vertical. Once you find something you like, use the REC button above the kaoss pad to lock it in, or adjust the knobs to the levels that you mimicked on the pad, or you could go to SEQ and set KX and KY to adjust at the steps you want. Trying to figure out where on the pad correlates to what position on the sequencer can be a bit tricky, so I just use the REC button, then clean up the sequence later. I should note, though, that using the kaoss pad and sequencer only gives you 16 distinct values for each knob, while manually adjusting the knob let's you get to values in between. You have been warned.

I will show you my patch I ended up with. It doesn't exactly sound like any Sega games I remember, but I'm happy with what I made. SYNTH and PATCH we already looked at, I just have both VCO set to triangle wave. Here is SEQ:

NOTE