Chapter 8: Vocal Synthesis

So this chapter is a highly requested one, and is something I researched a lot while I waited for DSN to be released. It's definitely more about linguistics than music, but it can be used in musical ways. If you've ever used the homebrew gameboy synth LSDJ, you may have come across the vocal samples built in to the recent updates. LSDJ has 42 "words" it can make. If you are interested, check out the list here, on page 57, but it's not necessary for us. Also, there is a popular YouTube video of somebody using vocal synthesis on DS-10, see it here. From what I can tell, it looks like he's only using DS-10 to make the vocals and not the rest of the song's sounds. His patch screen looks a bit different than what we will set up. Here his is, don't freak out:

To recreate what  that would look like is pictured here:

We don't need to do all that, though. Let's use "Disco" as our guide.

My interest definitely peaked when I saw the "Disco" promotional video for DSN, in which the song ends with the synth speaking its name. The demo song comes built into the DSN, check it out to hear some great examples of what this little app is capable of.

Formant synthesis is the term usually used for replicating vowel sounds this way. "Like an old speak and spell" is the best way to describe it. I could discuss the different sounds language makes in terms of fricatives and sonorants, but that's a complex subject I won't get into.

Let's start with vowels, because they are the clearest to hear and the easiest to replicate. Try making these sounds with your mouth (and nobody listening, so you don't look crazy). Keep your tongue pressed down and in one continuous breath, say "ah, eh, ee, oo, uh". Notice how you're mouth says open and you are using how open your mouth is to filter the sound. Your vocal cords are the oscillator. Diphthongs like ai and ey are actually two different sounds next to each other, in this case ah/ee for ai and eh/ee for ey. It just sounds like one sound because of how quick you change your mouth filter. 

Use the following patch. I noticed we get the best results with VCO2 set to triangle or square:

Now all we need to do is adjust the CUTOFF on the SYNTH page. Notice how there is a small range here that makes the vowels, if you open or close the filter too much, it no longer sounds like a voice. In fact, if I set CUTOFF to change with the KX sequencer, this is the only positions that have useable vowels:

There are actually good vowel sounds between those steps that you can get by manually setting the CUTOFF knob, I just wanted to show you the limits here. And playing the sequence at a slow tempo will give a good idea of what to listen for. By manually having your CUTOFF set to a spot between these positions and leaving some steps in the KX sequence blank, it will jump back to your manually set spot when the KX has nothing. I hope I wrote that in a way that makes sense. 

What I like to call the spitting consonants are made in a completely different way. Try making the following sounds with your mouth: "Kuh, Fuh, Huh, Puh, Suh, Tuh, SHuh, CHuh". Try it without the vowel sound at the end. Do you hear it? In addition to sounding like you are dismissively angry, these sounds are a lot like the hiss of the VCO1 noise wave, with different envelopes and filtering. Good, we already know how to change those, let's do this in the same setup we used before, with VCO2 patched to VCA. You can have KY switch VCO1 to noise by setting KY to VCO1 WAVE and putting it to max in the part of the word that is noise. This works good for S sounds, at least. It makes a sharper T kind of sound if you set your GATE to 25%. Telling the difference between S and SH would have to be a subtle change in CUTOFF, as far as I can tell.

Kuh was a tough one, but I think I got it. The trick is to set GATE to 50% for the step that K is on and change KX to VCF EG INT. Set up your KX so that it is in the spot 6 down. Like this:

Other consonants sound more like waves. Buh, Duh, Guh (like the g from gum), Juh, Luh, Muh, Nuh, Ruh, Vuh, Wuh. Also you don't spit the sound out like we did on those first consonants. These last consonants are the most difficult part to synthesize, and it's easy to not be able to discern them without hearing it with a vowel, it just sounds like another synthy sound. Try saying without a vowel sound at the end. It just stops. Making these sounds is done by using the filter EG INT on the vowel that comes after, reducing attack, and sending EG TO VCO2 PITCH IN. We can't separate these consonants from the vowels, but we really don't need to. Here is DEE:

On the VCF EG INT, it's really easy to go from DEE to YAY with just the smallest tweak. Finding the right points takes some careful movements. I also found a kind of WUH, or the first part of the word what, by messing with the ATTACK, VCF EG INT, and the PITCH IN knob. Check it:

Chaining together your sounds into words can be done in several ways. I just COPY the vowel setup and paste both the Sequence and the Tone across the patterns in the same Track row. From there, you can adjust as necessary for each sound, but you'd basically start from the same setup.

I haven't mapped out every sound, but I feel like we can get everything from the setups above. Please leave a comment if you run into any issues or need help with a specific word.


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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

GATE

PANNING

 KX

KY

Notice how my notes were the same throughout, but the sound was all over the place? FM has as much attitude as a blue hedgehog. 

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Chapter 5: Envelopes and Intensity

Pitch, Envelopes, and Intensity

Let’s start with [NEW] song again.

The first two knobs in the PITCH section is relatively simple. OCTAVE snaps to 5 different positions from low to high. PORTA is portamento, basically when you move between notes, it can make the pitch change glide instead of jump. Left is off, right is the slowest glide. 

The envelope is defined by ATTACK, DECAY, SUSTAIN, and RELEASE. These are common terms in the world of synths, there’s even a nice Wikipedia page. Your waveform is going to follow a pattern of volume changes when it is triggered (a note is pressed). Check out this chart that comes with the manual:

Attack is the start, rising in volume. Left is a sharp attack, it starts out at the full volume of your envelope and even has a bit of thump to how it starts. Moving right will make the rise more gradual, until you get all the way right and there is no attack at all. 

Decay is falling down to the sustain level. Left is quickest, fully right will skip the decay and sustain completely.

Sustain is the level the note will stay at for as long as you hold it down. It goes from nothing on the left to full volume on the right. It won’t go higher than the peak at the attack, because this is a very simple EG we are working with.

Release is really handy for recreating string sounds. Once you let go of a note, it will gradually reduce the volume, fully left goes straight to silent, going right makes the note last longer, fully right keeps it full volume forever, or until a new note is pressed and restarts the envelope.

What’s going on with the different EG INT knobs on the SYNTH screen were not immediately apparent to me. A quick glance at the manual says that the EG INT in both the PITCH section and the VCF section “adjust the amount of EG on a pitch” and can be “used for hitting sounds.” So basically, the envelope can shift the pitch, but how are these two knobs different? 

Experimenting around, the EG INT for PITCH is a bit like having an MG wave going into the VCO PITCH IN, only now the modulation is done by the wave that your Envelope is making. Now that chart is showing its worth, because it can show how not only the volume will change but also the pitch if the EG INT in PITCH is used. For this one, center is no pitch change, going right makes your attack rise in pitch, decay falls to the sustain pitch, and release falls from what your sustain was set to. Going left on this EG INT knob will do the opposite, meaning the attack will fall in pitch, decay will rise, and release will rise. Try these two configurations, holding down B for a few seconds, then letting the button go. 

The EG INT for VCF affects the CUTOFF, and seems to have the most noticeable change when the CUTOFF is set somewhere between left and center. Like this:

Try some PEAK in that configuration. That sounds pleasant. 

This EG INT does not have a reverse effect, its just a sliding scale of how much to raise (it never lowers) the CUTOFF, so set your CUTOFF knob set to your lowest desired position. On the PATCH screen, connecting EG to CUTOFF IN will get you the drop in CUTOFF by moving the knob towards the left. Try using both techniques seperately and together in different knob positions of CUTOFF, EG INT and the CUTOFF on the PATCH screen.  

On the PATCH screen, you can try connecting your EG to other things, the PITCH IN here has the same effect as we saw for the PITCH EG INT on the SYNTH screen, using both techniques together can make some interesting pitch changes. Remember PW IN only works on VCO1 in Pulse wave. Do this and you will see that in the left direction, your pulse gets fatter with attack, and to the right makes it get skinnier with attack. The oscilloscope on the top screen is magnificent!

If you connect EG to PITCH IN for just VCO1 and set up your synth so you have equal balance of both VCOs, you can have a changing pitch with a steady one. Turn on VCO SYNC and you just created a whole new wave that moves in pitch with no drone. I made one with both VCOs on triangle and it looks like a shark fin. I call it an ocean wave.

That’s all I can think to write about for this chapter. As you can see, EG Intensity can get really…intense. I’ll see myself out.

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