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BenQ Trevolo S Review


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  • Good battery life
  • 3D sound mode works quite well
  • Detailed, well-projected treble


  • Sound is not that cohesive
  • Conventional wireless speakers sound bigger, more powerful

Key Specifications

  • Review Price: £149
  • Electostatic panels
  • Bluetooth
  • Up to 18 hout battery life
  • Aux input
  • Dual passive radiators

What is the BenQ Trevolo S?

The BenQ Trevolo S is a portable Bluetooth speaker with unusual tech inside.

Most speakers this size use a combination of small drivers and a passive radiator that acts like a subwoofer. This one also has electrostatic panels.

These use a large, ultra-thin film that vibrates between two charged “stators”. Electrostatic drivers can often create much more transparent high-frequency sound than the average tweeter.

The BenQ Trevolo S is the first electrostatic portable speaker we’ve seen since the last Trevolo speaker BenQ made in 2015. Sound has improved. But so has the sound of more conventional rivals. The BenQ Trevolo S is interesting, but its sound quality is not all that competitive.

Related: Best Bluetooth speakers

BenQ Trevolo S portable electrostatic Bluetooth speaker.

BenQ Trevolo S — Design

The BenQ Trevolo S is a neat little speaker you can take around in a rucksack. Its electrostatic panels fold onto the main metal body, a 1kg thick brick of aluminium and plastic that feels very dense. Don’t let it drop onto a wood floor, it could do some real damage.

Electrostatic panels usually seem quite fragile, as the film inside is only a few microns thick, but the Trevolo S’s wings are well-armoured.

It’s not as ready for the road as something like the UE Boom 2, though. You just get a fabric pouch in the box, the Trevolo S is not water resistant and the smooth aluminium finish won’t stay smooth for long if you treat it rough. It’s like the Jam Heavy Metal or Bose SoundLink Mini II in this respect.

Hand holding BenQ Trevolo S electrostatic Bluetooth speaker.

Still, the BenQ Trevolo S will fit in your holiday luggage happily enough. The metallic grey with highlights of bronze around the speakers is perhaps a more grown-up look than the colourful fabric of the average rugged speaker.

Flip out the panels and it has an appearance similar to one of the old plug-in speaker docks, though. It’s not entirely on-trend.

BenQ Trevolo S portable electrostatic Bluetooth speaker.

BenQ Trevolo S — Features

Aside from the clever electrostatic tech, there’s nothing eye-opening going on inside the BenQ Trevolo S. It’s a Bluetooth wireless speaker that will play all the audio from your phone, including YouTube videos and game sound.

Pairing-up wirelessly is simple and quick, but there’s also NFC to let you hook up a compatible Android just by waving it over the NFC sensor on the BenQ Trevolo S’s top panel.

An aux input on the back lets you plug in a laptop or TV too, although these days many of those will allow a wireless Bluetooth connection anyway.

BenQ Trevolo S portable electrostatic Bluetooth speaker.

A series of six buttons on the top plate offer direct playback control. You can play/pause and change volume. The “mode” button simply switches the 3D sound feature on off. More on that later. The most important part of the BenQ Trevolo S is its electrostatic panels.

These are usually the preserve of hi-fi nerd speakers and headphones. They use an ultra-thin film of (usually) mylar that vibrates rapidly between two charged plates, controlled by an electrostatic field.

The main benefit is low distortion. A normal dynamic driver is a cone whose shape changes as it vibrates, where an electrostatic uses a bigger, flatter surface that stays, for the most part, flat.

Google the “Martin Logan Impression” and “Quad ESL 2912” for a look at some high-end electrostatic speakers. Their panels are huge.

BenQ Trevolo S electrostatic Bluetooth speaker displayed.

BenQ Trevolo S — Sound Quality

The problem with electrostatic speakers is they struggle to recreate bass frequencies. While their drivers are relatively large, they don’t have that much travel to them. This is why the BenQ Trevolo S also has two standard drivers and a pair of passive radiators, which pump air (and sound) out of the sides of the main unit.

Put your ear close to the BenQ Trevolo S’s various parts and you can hear how it works. To grossly simplify: it outputs treble from the panels, lower mids out of the front drivers and bass from the passive radiators.

Close-up of BenQ Trevolo S electrostatic Bluetooth speaker.

The BenQ Trevolo S reaches treble heights most Bluetooth speakers don’t touch for fear of making the sound harsh. Its electrostatic drivers project high frequencies very well, with more sibilance-free spark than even the studio monitors I occasionally use as a sound benchmark.

It works wonders for delicate songs like Kate Bush’s This Woman’s Work. However, feed the BenQ Trevolo S something that needs power and aggression, like IDLES’ Mother, and the speaker sounds weak and empty next to the Denon Envaya DSB250BT.

The speaker’s radiators aren’t as effective as those of the best small Bluetooth speakers either. Bass depth just isn’t that good. Kick drums don’t have as much of a thump as some, and the low-end is not particularly taut or fast.

Performance is too dependent on the style of music. The BenQ Trevolo S can sound good playing sparse arrangements with higher register vocals, but struggles with busy arrangements and rock.

The BenQ Trevolo S has to merge the sound from the panels, the active drivers and radiators, and it doesn’t do a perfect job. The sound isn’t entirely cohesive or smooth.

BenQ Trevolo S portable electrostatic Bluetooth speaker.

Audio has improved since the original Trevolo. Indie music no longer sounds like an ear-grating mess, but the effect is not gone entirely.

Sound width is not that great using the standard sound mode either. However, tap the mode button and the BenQ Trevolo S’s 3D audio feature kicks in. While just a EQ-style processing tweak, this improves the scale of the sound, helping it fill rooms better. The electrostatic panels do have relatively narrow dispersal, though, so positioning is important for the best results.

The concept of an electrostatic portable speaker sounds great, particularly if you’re a bit of an audio nerd who likes the idea of electrostatic and planar magnetic drivers that (in theory) reduce distortion. However, we need the results too. The BenQ Trevolo S sounds decent enough, but is outclassed by more conventional alternatives.

BenQ Trevolo S Bluetooth portable speaker on pink background.

Should I buy the BenQ Trevolo S?

The BenQ Trevolo S is a neat idea. But if you expect the sound usually associated with electrostatic drivers you may be disappointed.

While the sound is fine, it doesn’t have the scale or power of the best conventional Bluetooth speakers. If you’re out for a home speaker, the Sonos Play:1 is a much better choice, and is nowadays a similar price.

And for portable use? The Jam Heavy Metal costs less and sounds more powerful. And the Denon Envaya DSB-250BT sounds more cohesive, larger and smoother.


The BenQ Trevolo S’s portable electrostatic speaker concept is neat, but the results aren’t compelling enough.

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