Over the years, I’ve owned countless hardware synths, both
analog and digital. There are a few that I just had to keep because
they’re utterly unique. One of those is a Yamaha TX81Z. For many synth
aficionados, the 81Z was a bit of a trifle, even in its day. As Yamaha’s
FM synths go, it only had four operators, basic envelopes, and crunchy
digital-to-analog converters with more than a whisper of noise. But it
was also one of the most popular synths of the early house and rave
scene. In fact, its “Lately Bass” preset was a cousin of the DX100’s
“Solid Bass” patch that anchored countless tracks, notably Orbital’s
“Halcyon and On.”
So when Primal Audio’s new FM4 came out, I immediately
purchased it to see how close it got to the sound of a real TX81Z. The
specs indicated that they actually spent time and resources on
recreating the distinctive character of the Yamaha D-to-A converters, so
I was more than a little intrigued.
The user interface is brilliantly designed for an FM
synth. Everything is on one page, so there’s very little fussing around
whether you’re modifying one of the 128 factory presets or creating your
own. It’s all in plain view and as a sound designer, I love that kind
of attention to detail.
As with the 81Z, there are four operators, each with the
same eight unique waveforms that really defined the sound of the Yamaha.
Every operator includes the same ten parameters, neatly laid out in a
row: level, ADSR envelope, tuning, waveform, LFO depth, velocity
sensitivity, and keyboard tracking. With all these parameters within
easy reach, it’s quite clear what’s going on with your settings as you
Another lovely design touch is the way Primal Audio
implemented the TX81Z’s algorithm selector. As you flick through these
routing options, there are clear lines indicating the configuration next
to each operator’s on/off switch, so you can always see at a glance
which ones are carriers and modulators.
Also included is the 81Z’s selection of eight mircotuning
modes, which includes academic options such as Werckmeister and
Valotti-Young. While most users will likely ignore these options, there
are others who will be in heaven because of their presence here.
The LFO controls include the TX81Z’s waveforms, along with
both tempo-sync and triggered modes. Even the simple ramp-based pitch
“envelope” is in place.
Primal Audio’s enhancements to the architecture are
straightforward and functional. There’s a unison knob that can double,
triple, or quadruple-layer FM4’s voices for an added thickness that was
beyond the original’s scope. A “model” switch that toggles between three
different Yamaha D-to-A characteristics, with the most extreme option
reducing the presence and adding digital noise to the output, just like a
vintage unit. Finally, there’s a simple arpeggiator with up, down,
up/down, and random modes. I’ve always loved random arpeggiators, so
this addition really made me smile.
As for iOS features, CoreMIDI and Inter-App audio are in place, with Audiobus planned for an update by the time you read this.
After reviewing iOS apps for over five years, I’ve gotten
pretty finicky about “me-too” apps that don’t really bring anything new
to the table. FM4 is anything but that. It’s a distinctive soft synth
that does a fantastic job of capturing the sound of Yamaha’s
four-operator FM synths of yesteryear, with the added bonus of a
brilliantly designed interface. This may be Primal Audio’s first synth,
and I doubt it will be their last.
Spot-on recreation of Yamaha’s classic four-operator
synths. Eight microtuning modes. Brilliantly designed user interface
makes editing sounds a breeze. Unison mode adds needed thickness to FM
You still need to have a working knowledge of FM to edit your sounds intelligently.
Better than a real TX81Z in every way.
$9.99 download | primal-audio.com