Today, we’re diving into something really exciting—recreating iconic 4-op FM Sounds inDdexed. In particular, the famous ‘Lately Bass’ from the Yamaha TX81Z that was featured in the hit “What Is Love?” by Haddaway. What I had planned as a simple tutorial turned into an intriguing journey exploring the nuances of FM synthesis and how we can translate and adapt these classic sounds into Dexed’s 6-op architecture.
The points we’ll touch on in this post are:
- Finding parallels between the 4-op DX100 FM and the 6-op Dexed FM synthesis
- Other incarnations of 4-op FM in Yamaha synthesizers
- Understanding how to select Dexed Algorithms for 4-op sounds
- Manual and automated tools for conversion
What are the differences between 4-op and 6-op FM synthesis?
At a high level, the primary difference between 4-op synthesis and 6-op synthesis in Yamaha’s implementation of FM is (surprise, surprise) the number of Operators in an algorithm. As you may remember from our discussion about Dexed Operators, they are the sine waves that combine to generate audio into an FM synth.
There is however, there’s a larger difference – the number of algorithms present in the 4-op synthesizers that they released in the TX81Z era. Now, the TX81Z was the second generation of 4-op synths from Yamaha, the DX100 being one of the earlier generations. The TX81Z added the ability, which neither Dexed nor the DX7 ever had, to produce waveforms other than sine waves from the Operator. Still, it was confined to 8 algorithms. As it turns out, ‘Lately Bass’ uses only the sine waves in its Voice, so we can figure out a way to replicate this Voice in dexed.
There are other differences in the product lines as well. The DX100 is a feature-reduced DX7 with an even noisier output stage. Its Operators use only sine waves, like the DX7 and Dexed, for tone generations. The DX11 is essentially a keyboard version of the TX81Z, which added the waveforms below to its Operators:
Just note this for reference – we don’t need to be concerned with the additional waveforms in our study of Lately and Solid Bass. However, if you are considering a nice flexible hardware rackmount synth – the TX81Z may be for you.
How do we map TX81Z 4-op Algorithms to Dexed?
Here is a graphic showing the algorithms available to programmers in the TX81Z
As we found in our previous FM Percussive Voice post, the Algorithms in Dexed can provide the ability to generate “partial” tones – separate audio pathways via two or more carriers within the algorithm. Examine the chart above and carefully compare it to the chart of the 32 Algorithms available in Dexed:
This is a little small, so if you need a larger version like me, it’s here.
After staring at this for a while, I found that there was a mapping between the four Operator Algorithms in the TX81Z and dexed. In each case, one of the Carriers needed to be disabled. With this assumption, we can derive a table of 4-Op Algorithms that can be duplicated in Dexed:
| 4-Op Algorithm | 6-Op Algorithm | Dexed Operators to disable |
| 1 | 1 | 1, 2 |
| 2 | 14 | 1, 2 |
| 3 | 17 | 5, 6 |
| 4 | 7 | 1, 2 |
| 5 | 5 | 1, 2 |
| 6 | 24 | 1, 2 |
| 7 | 31 | 1, 2 |
| 8 | 32 | 1, 2 |
Note that when re-creating 4-op Algorithm, your parameters for Operators 2, 3, and 4 will be a bit more tricky; 4-op Operator 4 maps to Dexed Operator 2, Operator 3 to Dexed’s 4, etc. Beyond that one exception, the emulation of the 4-op Algorithms in Dexed is straightforward.
“Lately Bass” and “Solid Bass”
There is a healthy obsession with ‘Lately Bass’, as evidenced by searching for it on the Web. Your search results will show at least ten pages of links to sites that discuss the patch on various FM platforms. This is well-deserved – the Voice was a factory sound in the TX81Z that heavily contributed to a huge dance hit: “What Is Love?” Kudos to the Yamaha sound programming team and Haddaway as well. As with all things on the Internet, though, we need to analyze what search engines give us and chart our own way with the information provided.
There are many versions of the Lately Bass voice for the DX7 and subsequently Dexed. I listened to the Haddaway tune a couple of times before landing on what my ears tell me is the closest emulation. How did I make my selection? I first watched this video, where Ed Synth & Bass shows various velocity levels of the sound being played on a TX81Z, then on Arturia’s DX7V. Then, I found several versions of the Voice already converted to the DX7. Finally, watched this video where madFame converts Solid Bass (a different but very similar voice) directly from the DX100 to the DX7.
Translating the TX81Z version of Lately Bass to Dexed/DX7 is problematic because of one issue: the DX7 and Dexed only use sine waves in their Operators. On the TX81Z, as we mentioned, there are a few other waveforms available. Waveform #5 is used on Operator 3 in the selected TX81Z Algorithm 2. With some slight tweaks to a Dexed version of the sound, however, we can get very close – but not exactly. I’ve included several versions of Lately Bass in a cart in the “Resource” section below. There is also a version of Solid Bass, which was a DX100 patch and can be translated directly to dexed.
Step-by-step Translation from TX81Z to Dexed
If you have not already downloaded and installed dexed, please follow our tutorial to begin.
How to Convert the “Lately Bass” Voice from the Yamaha TX81Z to Dexed
1. Select the Algorithm:
• Open Dexed and choose Algorithm 14. This algorithm is closest to the structure of the TX81Z’s Lately Bass (Algorithm 2).
2. Disable Extra Operators:
• Dexed has 6 operators, but the TX81Z uses only 4. Disable Operators 1 and 2 by turning their output levels to zero or muting them. Focus on Operators 1–4 for the core sound.
3. Set the Operator Ratios: Adjust the operator frequency ratios in Dexed to match the Lately Bass settings:
- Operator 3: Set the frequency ratio to 0.5.
- Operator 4: Set the frequency ratio to 0.5.
- Operator 5: Set the frequency ratio to 1.00.
- Operator 6: Set the frequency ratio to 1.00.
- All active Operators have the “Ratio” switch set to “ON”
4. Adjust Operator Envelopes:
- Match the envelope characteristics from the image above to achieve the Lately Bass’s snappy attack and short sustain:
- For Operators 5 and 6, set a quick attack time and short decay to give it the percussive edge.
- Set Operator 3 and Operator 4 to a slightly longer decay for sustain and body in the bass sound.
- Note that the Envelope Rates don’t translate exactly. I recommend starting with the EG Rate 2s for Op 3, 5, and 6, at around 51, then adjust from there. Operators 3 and 4 release rates should be lengthened slightly to 92 or so.
- I was getting too much effect from OP6, so I adjusted Attack Level 1 to 94 to tame it. KeyVel is set to 7.
5. Set Feedback:
- Increase the feedback setting to add a touch of grit and fullness to the sound. Experiment with the feedback level until you get a similar metallic texture.
6. Fine-Tune and Detune:
- Adjust the slightly detuning Operator 4 to create a subtle phase shift, enhancing the bass’s metallic character. Just modify the Fine parameter one ‘tick’, so that f=0.505
7. Save the Patch:
- Once you’re happy with the sound, save your patch in Dexed to recall it easily for future projects. Keep in mind that we did nothing with the LFO → Pitch, AMD, dexed Filter, or the Pitch EG. You may experiment with these settings if you wish.
The platform also makes a difference. The fact that Dexed runs on a computer with reasonably high-quality digital-to-analog conversion resources will make the implementations sound different – Dexed will be cleaner than a DX7 or a DX100 or a TX81Z. That said, you can experiment with the PARM → Engine Resolution settings for Dexed to determine if any of these settings get either sound closer to the original.
How can I make this easier?
Honestly, it would be handy to know if translating 4-op FM synth voices to Dexed/DX7 6-op voices is a practical exercise and to see if one can make it easier through automation. There are two approaches that I have used in translating 4-op to 6-op voices. First we have discussed a bit – manually translating the Algorithms using the above table and manually entering all of the Operator parameters between the two synths. This may be fun a couple of times, but facing the conversion 32 voices from TX81Z to dexed would take a couple of hours. This is not my idea of fun.
What is fun, at least to me, however, is to set up Martin Tarenskeen’s DX to TX conversion tools found on his website. Martin has created an informative site with tools, downloads, and a little explanation of what he’s been up to in developing this Python toolkit. Essentially, you download his tools, download Python, and he offers instructions on how to take 4-op FM sounds and convert them to DX7 sounds (and I believe, vice versa). I have used the tools with great results, saving a lot of time converting banks of sounds from one format to another.
Wrap up
My original intentions for this post were disrupted by the realities of the Internet and the basic differences between TX81Z and Dexed FM synthesis engines. 4-op FM Sounds in dexed are possible, but there is some “tweaking” involved. There is a lot of inaccurate information on the web about Lately and Solid Bass. There’s a lot of good, fun stuff, too – including some great videos on comparisons between voices and Martin’s tools. While the “Experimentation” assignment of this post doesn’t have a dedicated section, it is to check out DXConvert/TXConvert and experiment with the Engine Resolution setting with your converted voices to see which one creates the closest emulation to your ears.
At SoundEngine.com, where we’re all about empowering you, whether you’re a professional sound designer or an audio enthusiast. Our mission is to fuel your creativity with high-quality sound libraries that won’t break the bank. With decades of experience crafting sounds, we give you mix-ready sounds that can elevate your projects.
In the next installment of the Dexed Owner’s Manual, we’ll take a look “under the hood” at a SoundEngine voice. We’ll start with a basic sound and build it to a custom sound that is unique and different. Until then, thank you for joining me today, and happy sound designing!
Resources:
- The Dexed plug-in:
- The LatelyBass and SolidBass patches discussed in this article:
- The sounds included with Dexed:
- FM Synthesis:
- SoundEngine’s Rebuild: Dexed (Sounds, documentation, and tutorials):
- Our custom programmed banks – Flywheel & Crankshaft: Dexed:
- The Complete Dexed Owner’s Manual Series:
Leave a Reply
You must be logged in to post a comment.