Bellos Audio X4

The reviewer calls bass the X4's highlight, praising its dynamic-driver sub-bass, convincing transition into the mid-bass, and visceral impact. Bass guitar and drum notes are described as deep, textured, and distinctly separated, with performance said to better much of what the reviewer has heard.

Midrange is described as lucid, thick, and warmly tilted without turning muddy or unclear. Vocals and guitars have notable heft and body, which the reviewer feels makes images sound more lifelike.

The upper range is lively and present, but the stock foam tips can make the lower treble bright. The reviewer found cymbal crashes splashy and the presence region potentially fatiguing, although alternate tips brought appreciably better control and linearity.

The X4 separates low-frequency elements particularly well, with bass runs, guitar notes, and drums retaining their own texture and position. The reviewer also finds the mids clear despite their warmth, while noting that the presentation is not especially crystalline.

The reviewer says the X4 gives instruments and voices corporeal body rather than presenting flat outlines. Direct comments on stage width and depth are limited, but the reported solidity of the images is encouraging.

Deep, visceral drums and the strong sub-bass-to-mid-bass handoff point to convincing dynamic drive and low-end integration. Its warm-neutral balance is also described as clear rather than muddy, supporting a cohesive overall presentation.

The matte finish is specifically said to produce a more consistent, grippy seal and to improve universal-fit ergonomics. The reviewer emphasizes that obtaining this seal is important and reports a favorable result.

The X4 is described as offering fantastic comfort. The reviewer adds that selecting the right ear tips makes it more comfortable still, so tip matching remains worthwhile.

Bellos specifies -17 dB of isolation for the X4. The reviews provide no direct commuting, stage-use, or side-by-side isolation impressions, so its real-world attenuation is not fully characterized.

The reviewer describes the X4 as a very well-built and attractive IEM, while Bellos lists a 3D-printed matte shell, RCX cable system, and two-year warranty coverage. The supplied material says little about the included case, tip assortment, cable handling, or longer-term durability.

At $999, the reviewer considers the X4 a benchmark in its price class. That assessment is driven by its standout bass performance, comfortable fit, and overall execution rather than by an extensive comparison list.