Introduction

Ultimate Ears has long been a favorite among music lovers for their colorful, rugged, and great-sounding portable speakers. With the release of the WONDERBOOM 4 in March 2025, they aim to build upon the success of their compact speaker line while introducing new features for the modern audio enthusiast. This fourth iteration promises improved sound, longer battery life, and enhanced connectivity options, all packed into the familiar softball-sized design. Let’s dive in to see if the WONDERBOOM 4 lives up to its predecessors’ legacy and stands out in the increasingly competitive portable speaker market.

Design and Build Quality

The WONDERBOOM 4 maintains the iconic cylindrical shape that has become synonymous with the series, but with some refined touches. Measuring 3.75 inches in diameter and 4.25 inches tall, it remains highly portable and easy to grip. The speaker is available in six vibrant colors: Phantom Black, Glacier White, Lagoon Blue, Crushed Ice Gray, Fiesta Red, and a new Eco Green made from 100% recycled fabric and 85% recycled plastic.

Build quality continues to be a strong point for Ultimate Ears. The WONDERBOOM 4 feels solid and durable, with a tightly woven fabric covering the speaker grille and robust rubber caps on the top and bottom. The large “+” and “-” volume buttons on the front remain a signature design element, now with a slightly more tactile feel for easier operation.

Ultimate Ears has improved the already impressive durability of the WONDERBOOM series. The WONDERBOOM 4 now boasts an IP68 rating, making it not only fully dustproof but also able to withstand submersion in up to 1.5 meters of water for 30 minutes. It also retains its ability to float, making it a perfect companion for pool parties or beach outings.

Sound Quality

Sound quality has always been a hallmark of the WONDERBOOM series, and the fourth generation takes it to new heights. Ultimate Ears has introduced their new 360° Adaptive Sound technology, which uses built-in microphones to analyze the speaker’s surroundings and adjust the audio output accordingly. This ensures optimal sound whether you’re in a small room, a large open space, or outdoors.

The WONDERBOOM 4 features two 40mm active drivers and two 46.1mm x 65.2mm passive radiators, delivering an impressive 360-degree sound. The bass response has been noticeably improved from the previous model, providing deeper, more impactful low frequencies without overwhelming the mids. Vocals and instruments in the mid-range come through with excellent clarity, while the highs remain crisp and detailed without becoming harsh at higher volumes.

One of the standout features is the new Outdoor Boost 2.0 mode. When activated, it not only increases the overall volume but also adjusts the EQ to emphasize frequencies that typically get lost in outdoor environments. The result is a louder, clearer sound that cuts through ambient noise more effectively than its predecessor.

The maximum volume has been increased by about 15% compared to the WONDERBOOM 3, allowing the speaker to fill larger spaces with ease. Even at top volumes, distortion is minimal, a testament to Ultimate Ears’ acoustic engineering.

Battery Life and Connectivity

Ultimate Ears has made significant strides in battery performance with the WONDERBOOM 4. It now boasts up to 16 hours of playtime, a 2-hour increase from its predecessor. In our tests, we consistently achieved between 14-15 hours at moderate volume levels. The speaker charges via USB-C, with fast charging support providing 3 hours of playtime from just 20 minutes of charging.

Connectivity has been upgraded to Bluetooth 5.3, ensuring a stable connection and support for the latest audio codecs, including AAC and aptX Adaptive. This allows for higher quality wireless audio transmission and lower latency. The Bluetooth range has been extended to about 50 feet, performing admirably even with obstacles in between.

Additional Features

The Ultimate Ears app has been revamped for the WONDERBOOM 4, offering more customization options and features. Users can access a 5-band EQ, adjust the intensity of the Outdoor Boost 2.0 mode, and control the 360° Adaptive Sound feature. The app also allows for easy firmware updates and battery monitoring.

PartyUp, Ultimate Ears’ feature for connecting multiple compatible speakers, has been improved. You can now connect up to 50 WONDERBOOM 4 speakers (or other compatible Ultimate Ears speakers) for synchronized playback, perfect for large gatherings or creating a multi-room audio setup.

New to the WONDERBOOM 4 is a built-in microphone for hands-free calling and voice assistant access. A long press of the central button activates your phone’s voice assistant, adding a layer of convenience to the speaker’s functionality. Call quality is good, with the speaker’s 360-degree sound design ensuring clear audio on both ends of the conversation.

Conclusion

The Ultimate Ears WONDERBOOM 4 represents a significant evolution in the compact portable speaker market. It successfully builds upon the strengths of its predecessors while introducing meaningful improvements and innovative features. The combination of improved sound quality, longer battery life, and enhanced durability makes it a versatile and powerful portable speaker.

Priced at $99.99, the WONDERBOOM 4 offers exceptional value in the competitive portable Bluetooth speaker market. Its performance and feature set rival many more expensive options, making it an excellent choice for those seeking high-quality audio in a compact, rugged package. The improved durability and adaptive sound features make it suitable for a wide range of environments, from indoor use to outdoor adventures.

For those in the market for a portable Bluetooth speaker that delivers impressive sound quality, robust build, and user-friendly features, the Ultimate Ears WONDERBOOM 4 should be at the top of the list. It’s not just an incremental update but a refinement of an already excellent product line. Whether you’re a long-time fan of the WONDERBOOM series or new to Ultimate Ears, the WONDERBOOM 4 is sure to impress, cementing its place as one of the best compact portable speakers of 2025.