Preen/FM synth question

This is a tricky tech question, and I’m guessing Mutable folks have the knowledge base to answer this question.

There are two FM synths I really love: PreenFM2, and Korg 707. To my ears, they just sound huge, 3D, the oscillators easily phase in and out of each other real nicely, and they have all the character of analog synths, just in a digital way. And they sound MUCH fuller to my ears than software.

So I’ve been looking for other hardware FM/digital synths that sound as good, but can complement these with other options. Here’s an example of the sort of sounds I’m looking for: https://www.youtube.com/watch?v=7OQ3s8rfHVA. All the easy tweaking and in between sounds are great to my ears, and fit my spacerock meets industrial music. Not into ambient, I like my FM full and flangey, and the Korgs and Preen have that, and decent user interface helps get that.

But looking for other FM/digital synths which are also like this has been difficult. Demos of the DX7 MkI and Casio CZ series seem woolly and noisy. Tried the Yamaha Dx200 and it sounded real sterile and flat. Just played with a Korg Kronos with its Mod-7 VPM/FM engine, fun waveshaping with the FM, but still sounds too refined, too tame, too much like software. Kawai K5000s without its effects sounded really thin to me. I’d like to try a Yamaha SY line, or maybe a Casio VZ, or a TX802 or DX7II, but seems so much overlap with the Preen.

Here’s my question: TECHNICALLY speaking, what is it that the 707 and the Preen have in common that is making them sound good? One is 4op 16 bit FM, and the Preen is sort of 18 bit. Both just sound to me like they have real depth to their sound. Maybe it’s just better stereo imaging, or maybe easy tweaking is allowing me to just get those types of sounds better. But they seem technically quite different in terms of processors, DACs, etc. What makes these sound good? And knowing that, should I be looking now at the Yamaha SY line, Alesis Fusion, or something else? Or just use FM8 for the rest, cause the more refined hardware will start sounding like softsynths?

What makes hardware digital, when you strip the effects away, sometimes sound full and like HARDWARE, and others sound plasticky? An Sq-80, even if you use just digital with no filters, sounds brittle but still phasey and organic and not like software. Is it just the 12bit waves layered and detuned into a hardware amp? I also played a teenage engineering OP-1 recently, maybe too quickly, but while it had a ton of bass, it also sounded a bit flat and plastic to my ears. What does that?

Without saying too much about FM, I think that one quite basic difference between hardware and software synths is that the former may have some character in the DA conversion and amplification stage. Often it can be mimicked with just some EQ’ing. One example of great DA/amplification stage is Ensoniq ASR-10. Even if you don’t do any manipulation of a sample (and there are tons of possibilities) everything sounds (subjectively) better just going through it.

Cheers

PS Then I guess there may actually be algorithmic/implementation FM differences as well DS

I noticed the same with my Analog Rytm. Playing samples through it makes them sound more “analog”. I guess it’s coming down to distortion. The Rytm has plenty of saturation/distortion - you can notice easily when all tracks have a high volume: It just gets muddy. On the other hand that means that - with lower volumes - you get a more gentle saturation that makes anything sound warmer.

Applying saturation gently will make anything sound more like “hardware”. So maybe you can get good results by adding a tube emulation/saturation/tape saturation effect after the FM8? I’m using the Vintage Compressor series and the vintage EQs from native Instruments and even without noticeable compression/EQ I can hear a difference that makes things a little warmer. I don’t always like it though.

Another trick that I like is running audio through my tapedeck, without actually writing it to the tape. I set the switches to “input monitoring” and run the audio through the deck. It never passes the record/play heads but instead directly goes from the input stages to the output stages. The old transistor-amplifier stages add plenty of hiss/noise but also plenty of nice saturation. You can even control the amount of saturation with the input gain. I can’t tell what exactly is happening, but it just sounds better. BTW: I actually like the noise and leave it in there mostly. When its not wanted, I can add a high frequency gain before the tapedeck and a high frequency cut after the deck - thus reducing the volume of the noise without altering the original sound too much. Kind of an analog empahasis.

Anyways - to my ears, “analog sound” comes down to a combination of noise and the right type of distortion.

As far as I have read there are a few factors…the most important is the resolution of the tables used to create the waveforms and the clock speed of the DAC. The sampling rate / bit depth was actually pretty high on the old DXs (e.g. 12bit / 49kHz on the DX7). The early Yamaha chips (e.g. the 2164 in the 707) had very fast clocks (at 4mHz) which too me gives them ‘punch’…I can’t remember what the clock of the preen is but I remember thinking that it was fast. As I remember the later SY/TG chips were the normal 44.1 / 48 khz which is not even in the same ballpark. So far I have seen no soft synth that states specifically that it has settings to emulate these factors in the sound (the FM4 ipad app has the vague ‘vintage’ settings). I thought about a preen many times because I like tiny black boxes, but I like the vibe of the old stuff. I can fit all the paramters on two ipad pages, so the 707 is the easiest to control via MIDI (or those three sliders). If you are a computer user there is the great CTRLR editor for both the DS8 and 707. The 707’s architecture is exactly the same as the DX27 and DX100…they have access to each operator / algorithm but neither have aftertouch. A fun alternative is the TQ5. It is a DX11 / TX81z descendant with crunchy built in effects.

Hadn’t even thought of the clock speed! What exactly does lock speed do to the sound? I’m not sure if ‘punch’ is what I’m looking for as much as the dimensionality or depth, but maybe clock speed is what I’m hearing.

It could of course be gain stage and distortion (nice tip on using a tape deck mixer), which I’d figure in an older item like the 707, but not the Preen, though maybe as a DIY box it’s got a relatively cheap amp circuit in it?

Btw, can’t say enough good about the Preen, it’s really excellent. Got mine built from Raph at Michigan Synth Works, highly recommended!

The FS1R can sound really nasty and also nice. They get hyped a heck of a lot though and the prices are high. I bought one last year and I’m pleased with it.

Korg Prophecy and Z1 have an FM oscillator model. I can’t remember how advanced it was, I sold my Prophecy years ago.