A rompler is an electronic music instrument that plays pre fabricated sounds based on audio samples. In contrast to samplers, romplers do not record audio and have limited or no capability for generating original sounds. The term rompler is a portmanteau of the terms ROM and sampler. Both may have additional sound editing features, such as layering several waveforms and modulation with ADSR envelopes and LFOs.
The term rompler most often describes sample based software instruments such as VSTis. These do not have the ability to record new samples; instead, samples are replayed from computer RAM after they are loaded from disk. Popular examples of software romplers are reFX Nexus and IK Multimedia Sampletank. In this context, a software instrument can only be considered a rompler if it restricts the user to certain bundled sounds, without allowing them to load their own samples.
Hardware synthesizers that use a sampled waveform are not regarded as Romplers and are known as PCM-based synthesizers because the sampled waveform is not such that would be used or captured with a sampler, a PCM waveform is usually only made of a single full cycle of the wave and would therefore be a fraction of a second in length where as a sampler or rompler would usually play samples of a much larger size of at least several cycles long such as a recorded drum hit or piano note.