Since the 1990s, software synthesizers, sometimes called "softsynths," have replaced the hardware synthesizers they emulate. In many cases, they can emulate hardware synthesizers like MiniMoog or Alpha Juno with perfect precision, while being more customizable and flexible than the originals. There are five software synthesizers in particular that are generally recognized by professionals for their quality and depth. However, choosing the five "best" software synthesizers will depend on the individual user's tastes and requirements. Reaktor is a powerful modular synthesizer from Native Instruments. A "modular" synthesizer allows users to design their own instruments by connecting individual "modules" that emulate basic mechanisms of audio synthesis, such as oscillators and LFOs. The different elements can be interconnected with virtual "wires" in the way desired by the user, making Reaktor highly customizable. Reaktor is widely used by professionals in both music production and sound design and can be heard in everything from popular to avant-garde music. Spectrasonics' Omnisphere is primarily a sample-based synthesizer. This means it uses recorded samples as a starting point for sound generation, morphing, filtering or modulating according to user specifications. In particular, Omnisphere is used professionally to create unique pads and other atmospheric sound material. In this capacity he is considered unsurpassed by some professionals. Of all the synthesizers listed here, Omnisphere is the most resource-intensive and requires powerful hardware to run. LennarDigital's Sylenth1 is known among professionals for its accurate emulations of traditional analog synthesizers. “Sample-accurate” means that, under careful analysis, the sounds produced by Sylenth1 are indistinguishable from those of the hardware it emulates. Sylenth1 is a subtractive synthesizer. It produces sound by subtracting specified frequencies or harmonics from the oscillator's output and remixing them into any combination desired by the user. Massive is a hybrid synthesizer from Native Instruments. “Hybrid” means that it combines two or more types of synthesis – in this case granular, additive and subtractive elements – to produce sound. Known particularly for his lead vocals and bass skills, Massive is often associated with trance and similar subgenres of electronic music. It is also known as one of the most accessible software synthesizers for amateurs. Like Omnisphere, Camel Audio's Alchemy is a sample-based hybrid software synthesizer..