|Oscillator||4 operators per voice
|LFO||2 in performance as well as dedicated vibrato(multitimbral) mode
1 in single voice mode
assignable to pitch or amplitude
|Synthesis type||Digital Frequency modulation|
|Memory||128 factory patches
32 user patches
24 user performances
|Effects||Pseudo-reverb for each voice|
The Yamaha TX81Z is a rack-mounted (keyboard-less) frequency modulation music synthesizer, which was released in 1987. Unlike previous FM synthesizers of the era, the TX81Z was the first to offer a range of oscillator waveforms other than just sine waves, conferring the new timbres of some of its patches when compared to older, sine-only FM synths. The TX81Z has developed a famous reputation, largely based on some of its preset bass sounds.
The unit is multitimbral, and has 128 ROM slots and 32 RAM slots. The RAM slots were rarely utilized due to the perceived high quality and usability of the original patches and the difficulty of programming new sounds with the limited front-panel interface. Among the presets is the famous LatelyBass, one of the most popular presets in synthesizer history.
The TX81Z is backwards-compatible with sound patches developed for Yamaha's DX21, DX27, and DX100 synthesizers. It is also very similar, and almost completely patch-compatible, to the DX11 synthesizer, which is essentially a TX81Z with a velocity and pressure-sensing keyboard, and a pitch envelope.
The many faces of the TX81Z
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Some say the prevalence of the TX81Z's presets was also because of the difficulty in creating new patches. Creating new sounds from the unit's front panel is possible, but numerous nested parameters must be navigated by way of 11 buttons and a backlit 16 character, 2-line LCD. However, several personal computer-based editing applications have been developed since its release. The Dutch company KissBox released in 2013 a TX81Z editor based on RTP-MIDI communication, which makes the hardware synth appear as a VST plugin, while being controlled over a network link in real-time.
The TX81Z was designed as a low-cost FM machine and has always been relatively inexpensive compared to most other FM synthesizers. The TX81Z is built around a single FM chip, known as the Yamaha YM2414B ak OPZ, while other machines like the DX7 are built around a chipset (typically EGS chip for envelope generation + OP chip for signal generation). The 63B03 CPU is in charge of LFO generation, in parallel with MIDI and user interface management. Since the YM2414 is a hardware FM generator (not a DSP running software), the TX81Z is strictly limited to the capabilities of this chip. In particular, the operators can not be reallocated dynamically, making the polyphony limit to 8 voices, even if some voices are not using the all four operators.
The TX81Z can run quite quickly out of resources, especially under Performance Mode, where the 8 voices are shared between the 16 MIDI channels. It is also quite sensitive to System Exclusive messages timing when being edited remotely. Special care must be taken not to send System Exclusive messages with a delay too small between them (it can take up to 50ms for the synthesizer to process a new parameter value).
The low price made the TX81Z popular with many producers on a tight budget, and is still used by part-time house and acid house producers. Eliot Kennedy uses it for one purpose, a "classic dancefloor bass sound.". Producer Babyface at one point had two units in his studio, both of which he kept set to the preset "LatelyBass", one detuned from the other; this expanded version of the preset became a part of his signature sound. TX81Z units are still fairly common and can often be found at pawn shops, second-hand music retailers, and internet auction websites.
- Sellars, Paul (October 1999). "Yamaha TX81Z: FM Synth (Retro) – Paul Sellars goes back to a time when minimalism ruled in synth design...". Sound On Sound. Retrieved September 5, 2011.