The FR-5b features a 128-voice polyphonic sound engine, 428 tones in 40 accordion sets (each including 14 Treble registers, 7 Bass registers, 7 Free Bass registers, 7 Orchestral Bass registers, 7 Orchestra Chord registers, 7 Orchestra Free Bass registers and 22 Orchestral Sounds).

At the heart of the FR-5b, is Roland’s proprietary PBM technology for breathtaking sounds and amazing modelling possibilities. Physical Behaviour Modelling uses complex algorithms for accurate recreations of every detail of a wide variety of acoustic accordions. All physical behavior aspects and expressive nuances of an acoustic instrument are faithfully reproduced.

The FR-5b is capable of simulating up to 40 different accordions (or to create as many virtual instruments)based on samples of popular traditional acoustic accordions, each with its own "idiosyncratic" tuning. It is possible to switch from an Italian Jazz accordion to German folk, French Musette or a historic Bandoneon sound - without physical modifications to the instrument itself. On top of that, each sound can be played using the same familiar accordion techniques.

The FR-5b incorporates Roland’s acclaimed orchestral sounds. 22 orchestral sounds are provided, while each bass section (bass, chord, free bass) can trigger its own orchestral sounds.

The V-Accordion faithfully reproduces the familiar sounds and nuances of a traditional accordion, while granting the versatility, flexibility and advantages of a digital musical instrument.
You can select and switch between a wide range of sounds and/or accordion types, or create your own unique timbres. Furhermore, both keyboards can be transposed to play within a wide range of keys and octaves.

The V-Accordion introduces revolutionary expressiveness for a digital musical instrument.
The right- and left-hand keyboards are both velocity-sensitive, while a master bar adds even more creative options (including aftertouch control). The high-resolution bellows pressure sensor provides amazing expressive power, not available on conventional digital keyboard instruments.
Utilizing the high/low modes (notes above/below the first key you press play a different sound), you can control up to 4 parts simultaneously in realtime.
Also the FR-5b‘s bass section has been expanded to include control of additional orchestral sounds via the orchestral chord and orchestral free bass sections.
Moreover, the FR-5b is MIDI-compatible and can be used to control external modules.