Size notwithstanding, the Celsus SP-ONE speaker can fill a room with audiophile-quality sound. The SP-ONE’s expansive soundstage, commanding bass and overall musicality puts it at the forefront of bookshelf designs. For more personal applications, the SP-ONE’s excellent nearfield characteristics, especially at low volume settings, makes it the perfect desktop companion.
Celsus SP-ONE comes in two models. The Active model includes power amplifier and bluetooth wireless audio where it can be used as a standalone wireless speaker or to receive music from external source device. For audiophiles who want to get the best performance out of SP-ONE’s unique speaker driver and acoustic design, they can consider using an external high performance amplifier with the Passive model.
Design features that enable SP-One to outperform similar speakers

3.5” Deep Bass Carbon Fiber Woofer
A carbon-fiber cone woven from thousands of ultra-fine carbon fiber yarn features these advantages:
- The rigidity (Young’s modulus) is three times that of glass fiber, twice that of Kevlar fiber, and 20 times the strength of iron. It effectively inhibits split-vibration frequency distortion, resulting in miniscule dynamic deformations.
- Low mass (lighter than aluminum) permits high electro-acoustic conversion efficiency with the ability to closely follow the electrical signal’s transient response, with the added benefit of high sensitivity and an impressive SPL.
- Insensitive to changes in humidity and temperature, thus offering excellent stability over long periods of time.
- Patent pending folding ring design – For small and mid size speakers, the traditional folding ring design has a deficiency that resulted in 10dB frequency curve valley in the 2kHz region. This will affect the vocal richness of the music. The Celsus Sound folding ring design solves this dynamic nonlinear distortion problem and improves overall frequency response.
The carbon-fiber cone produces dynamic and powerful bass, smooth, detailed sound and a wide sound stage.

Typical Design
For small and mid size speakers, the traditional folding ring design has a deficiency that resulted in 10dB frequency curve valley in the 2kHz region. This will affect the vocal richness of the music.

SP One Design
The Celsus Sound folding ring design solves this dynamic nonlinear distortion problem and improves overall frequency response.
Tweeter
Tweeter: soft dome, horn-loaded driver for a wide dispersion of highs – a design that lowers the crossover frequency in order to achieve a flatter frequency response. The soft-dome tweeter’s high-energy magnetic flux and self-cooling capability together produce an audibly clearer signal.


The SP-One’s double cavity and pot design allows for a bass reflex design capable of delivering powerful dynamics.


CD-quality Bluetooth sound: together, the 4.0 Bluetooth transmitter and receiver module with aptX technology plus the SP-One’s noise-reduction circuit deliver CD-quality sound.