[Listening test] Superlux BES 3.5 - active studio mini-monitors

Product: Superlux BES 3.5 - active mini monitors
Manufacturer: Superlux - Taiwan
Price: €70/pair
Reviewer: Lucio Cadeddu - TNT-Audio Italy
Reviewed: March, 2026

Superlux is a Taiwanese brand well known among audio enthusiasts for a series of headphones offering an excellent price-to-performance ratio - something I was able to confirm very positively in my review of the HD 681 model.

However, not everyone knows that Superlux also produces a rather extensive line of active studio monitors, ranging from the small BES3.5 model reviewed here to the top-of-the-line BES8, equipped - just as the name suggests - with an 8-inch (20 cm) woofer. The range also includes two subwoofers.

A Closer Look

As the name implies, the BES3.5 uses a compact 3.5-inch (9 cm) midwoofer crossed at 3 kHz with a 1-inch fabric dome tweeter. The woofer is not filtered and there's just a capacitor on the tweeter. The drivers are reflex-loaded through a rear-firing port. Powering the system is an internal amplifier (located in one of the two speakers, the other being passive) based on the TDA 7265 chip, which - unusually for this price range - is not Class D but Class AB. This chip can be powered up to 25 V and has a maximum rated output of 20+20 watts at 1% THD (both on 4 and 8Ω). Superlux claims 50 watts, but this evidently refers to the maximum combined L+R output at 10% THD, the classic accounting trick used to make specs look better than they are.

The cabinet is made of MDF and contains no internal damping material, while a moulded plastic front panel adds a touch of refinement. Curiously, the tweeter is mounted in a plastic housing that is then fixed to the cabinet. The woofer, though small, appears to be of good quality and features a magnet assembly as large as the diaphragm itself. The diaphragm material seems to be aramid fibre, although the manufacturer does not explicitly state this.

The power chip is mounted on an aluminium heat-sink to dissipate heat, and a bank of four 1000 uF capacitors supplies the power section. The power supply is internal, so setup is simple: connect the power cable, the speaker cable (via spring-loaded terminals) to the passive unit, and the BES3.5s are ready to play.

Inputs are line-level only - RCA, 3.5 mm minijack, or TRS - so there are no digital inputs and no Bluetooth. To enrich the otherwise essential feature set, there are bass and treble tone controls with a ±3 dB range (though the operating frequencies are not specified). On the front of the master speaker are the volume knob, the power button (with a green LED that is slightly too bright), and a convenient 3.5 mm headphone output. The package includes a minijack-to-minijack cable, the power cable, the speaker cable, and a small user manual. These are the declared technical specifications:

From Headphones to Studio Monitors

These Superlux BES3.5 are truly compact and ideal for small home studios or as a first pair of active speakers for a minimalist setup driven by a PC, smartphone, or any line-level source.

As a reference sparring partner - due to similar size and price - I chose the first-generation Lonpoo LP42X (the only Lonpoo active speaker that actually sounds good), equipped with a 4" carbon fibre midwoofer.

The tonal balance of the BES3.5 is, contrary to my expectations, slightly tilted toward the bass frequencies, perhaps to compensate for the very small woofer. On standard speaker stands (about 70 cm high), the BES3.5 can be placed fairly far from the rear wall to avoid additional bass reinforcement. The tone controls, although limited in range (±3 dB), can help fine-tune the response depending on placement. On a desk, for example, they would sit too close to the rear wall, so increasing the treble and/or reducing the bass may be necessary.

The specifications claim bass extension down to 80 Hz at -3 dB. This figure may be a bit optimistic, but the performance is still surprising given the compact size of both the cabinet and the woofer. Port noise is not particularly noticeable, which is unexpected. There are some hints of boominess and resonance in the bass and mid-bass; the lack of internal damping likely contributes to this.

In the midrange, the BES3.5 reveals its limitations, thinning out vocals and reducing the body (and attack time) of percussion instruments. The overall presentation has a slightly artificial, sometimes metallic character, with limited harmonic richness. Moving into the treble, things improve: guitars and cymbals sound crisp and reasonably present. The overall tonality leans toward a loudness curve but remains pleasant enough. You can clearly tell this is a very inexpensive speaker - there's no hiding that.

Overall transparency, precision, and naturalness fall short of other active monitors I've tested, and the Lonpoo LP42X is a tough comparison in this regard. The sound also feels smaller. A modern Class-D amplifier chip would likely have delivered more oomph - more power, dynamics, and control - than the modest TDA 7265 chipset, which was designed for non-audiophile applications.

Midrange dynamics are limited, and toms, snares, and other transient sounds are reproduced with excessive restraint. The speakers can play fairly loud overall, but it's clear that their intended use is desktop listening or sound reinforcement in a small room. The claimed 100 dB SPL seems optimistic or is measured at 1 meter (not specified). The competitor Lonpoo LP42X plays both louder and bigger, projecting sound more convincingly into the surrounding space. The BES3.5, while offering a decent horizontal sound-stage, struggles to detach the sound from the speakers.

In summary, the BES3.5 is excellent for desktop use but shows its limits when asked to fill a medium-sized room. This is not so much due to maximum SPL - which may be sufficient - but rather to the inherently small-scale presentation. Placed 75 cm off the floor and spaced more than 2 meters apart, these little speakers start to feel lost (which is understandable - they weren't designed for this use).

Remarks and Complaints

Build and Finish. Considering the price (70 euros per pair!), there's little to complain about. They feel sturdy and are nicely finished. The green power LED is too bright and is best dimmed with tape. The tone controls prove to be useful for adapting the sound to different setups.
Sound. Not the most precise or transparent, and the slightly boomy mid-bass doesn't help clarity. Without a direct comparison to the old LP42X, the BES3.5 still manages to impress given its value for money.

Conclusions

The Superlux BES3.5 offers respectable performance at an incredibly low price; expecting more would be unreasonable. For 70 euros you can barely buy a low-quality Bluetooth speaker, yet here you get a pair of active speakers capable of giving a PC a pleasant, lively sound on a desk, or even performing decently on stands or a bookshelf - as long as they are positioned at seated ear height. The Lonpoo LP42X costs (did cost, indeed!) a bit more and sounds significantly better, but it is unfortunately discontinued. Its replacement with digital inputs (including the LP42M) sound quite poor. At this point, I'm very curious to try the BES5 with 5-inch woofers; perhaps some of the shortcomings of the small BES3.5 can be addressed.

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Superlux BES 3.5

Extra-small active studio monitors

A Closer Look

From Headphones to Studio Monitors

Remarks and Complaints

Conclusions