Astell&Kern, the world leader in high-resolution audio, has announced the launch of its newest flagship digital audio player, the A&ultima SP4000. The SP4000 is the result of three years of development and represents the pinnacle of the company’s engineering, offering unmatched sound fidelity, refined design, and next-generation features. Alongside the player, Astell&Kern will also showcase two new in-ear monitors (IEMs) that are scheduled for release in the third quarter of 2025.
The SP4000 builds upon the legacy of the SP3000, once regarded as the ultimate reference player, by introducing an all-new Octa Audio Circuit architecture. For the first time, Astell&Kern has implemented a one-to-one pairing of the AK4191 digital processor with the AK4499EX DAC, achieving a true Quad DAC configuration. By physically separating digital and analogue signal processing, the player reduces noise while enhancing precision, producing sound that is more natural, detailed, and immersive than ever before. This design breakthrough marks a milestone in digital audio engineering.
To further elevate performance, the SP4000 introduces a High Driving Mode using dual OPAMPs in parallel for greater dynamic range and stability without adding noise. Astell&Kern has also developed proprietary Enhanced Signal Alignment (ESA) technology, which minimises group delay and ensures frequencies arrive in sync, delivering clearer imaging and improved timing. An Ultra Low Noise LDO Regulator, borrowed from medical and 5G applications, suppresses noise by up to 97 per cent, while the second-generation Digital Audio Remaster (DAR) technology employs a two-step process that virtually restores lost harmonics before upsampling audio for a more natural, lifelike sound reproduction.
Beyond pure audio performance, the SP4000 integrates full Android OS support for the first time in Astell&Kern’s flagship line, allowing installation of apps directly from the Google Play Store. With the brand’s proprietary ADP (Astell&Kern Direct Path) technology, the device bypasses Android’s usual sampling limitations to deliver bit-perfect, lossless playback—even when streaming. Paired with advanced engineering such as Any Layer HDI PCB technology, a 99.9% pure copper shield, and a new 4.5 generation Crimson-themed user interface, the SP4000 balances uncompromising performance with ease of use.
The device features a premium design made from 904L stainless steel and comes packaged with a handcrafted leather case from Perlinger, Germany’s renowned tannery. It offers a 6-inch 2160×1080 display, 256GB of internal storage (expandable to 1.5TB), support for high-resolution formats up to 32-bit/768kHz PCM and DSD512, and wireless connectivity with aptX Adaptive and LDAC. Additional highlights include ReplayGain for volume normalisation, wireless file transfers via AK File Drop, DLNA streaming, USB DAC functionality, Qualcomm QC 3.0 fast charging, and a Crossfeed mode that mimics a speaker-like experience for headphone listeners. Roon Ready certification is also on the way.
In addition to the SP4000, Astell&Kern will preview two exciting new in-ear monitors set for release in Q3 2025. The first is a collaboration with 64 Audio, featuring a 10-driver universal fit design with a true isobaric driver configuration, housed in polished 904L stainless steel with a black DLC coating. This unique construction ensures reduced distortion and unmatched precision. The second, named Luna, is developed in-house by Astell&Kern and features a full-range unipolar micro planar magnetic driver with a frequency response of 20Hz–30kHz. It comes paired with a premium Eletech silver-coated OCC and copper OCC balanced cable.
Both the 64 Audio collaboration IEM and the Astell&Kern Luna will be available globally in the third quarter of 2025, with pricing details to be announced closer to launch.
Together with the SP4000, they reflect Astell&Kern’s ongoing mission to push the boundaries of portable high-resolution audio and deliver products that bring listeners closer to the original sound.
The Astell&Kern SP4000 retails at SGD 5,999, and to pre-order, click here.
