BENQ's TreVolo Electrostatic Bluetooth Speaker System Reviewed

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Introduction To The BENQ TreVolo Electrostatic Bluetooth Speaker System

BENQ TreVolo Electrostatic Bluetooth Speaker - Speakers Open
BENQ TreVolo Electrostatic Bluetooth Speaker - Speakers Open. Image provided by Amazon

A Video Projector Company Does Audio?

Attending the annual CES gives me a great opportunity to get briefed, as well as see and hear demos of up-and-coming home theater products, such as TVs, home theater receivers, media streamers, and more, including lots of loudspeakers. However, in addition to products that are directly associated with home theater, additional products sometimes grab my attention. At the 2015 CES one such product was the BENQ TreVolo Bluetooth-enabled compact audio system.

The first thing that grabbed my attention is that the TreVolo is not made by a traditional audio company, but by BENQ, a noted video projector maker. After getting over that initial oddness, there is more - It turns out that the  BENQ TreVolo is not your ordinary compact audio system, it incorporates Electrostatic speaker technology that is almost exclusively used on very high-end select speaker systems. The most prominent company that employs this type of speaker technology is Martin Logan (Check out their page on how Electrostatic Speakers Work).

Briefly, instead of traditional cones and magnets (which require a box or cylinder cabinet construction), Electrostatic speakers produce sound by vibrating a diaphragm suspended between two metal grid. The metal grids generate an electrostatic field that vibrates the diaphragm, which produces sound. This results in a very thin design.

However, the downside of Electrostatic speakers is that although they produce mid-range and high frequencies well, they don't do well with lower bass frequencies. As a result, standard woofer or subwoofer is still required for a full-wide frequency range listening experience, which BENQ takes into account in the design of the TreVolo.

Shown in the above photo is the retail packaging the BENQ TreVolo comes in.​

BENQ TreVolo Features and Specifications

  • System Type: Self powered (via AC or rechargeable battery) Bluetooth-enabled compact audio system
  • Loudspeakers: Two fold-out Electrostatic driver panels, and two 2.5-inch cone-type woofers supported by oval passive radiators.
  • Amplifier: Quad Amplifier design (separate 10-watt amplifiers for each electrostatic panel and woofer speaker)
  • Stated Frequency Response: 60Hz - 20kHz
  • Bluetooth Compatibility: Version 4.1 with AptX.
  • Physical Connections: Analog Stereo (3.5mm) In and Out, USB port (micro), and plug-in power receptacle.
  • Other Features: Built-in microphone for speakerphone function.
  • Dimensions: 174.6x134.6x78.5mm (6.87x5.3x3.09) inches (Closed)
  • Weight: 1.2 kg (2.6 lbs)
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BENQ TreVolo Package Contents

BENQ TreVolo Package Contents
BENQ TreVolo Package Contents. Photo © Robert Silva - Licensed to

Here is a look at what you get in the BENQ TreVolo package.

From left to right is the AC Power Adapter and User Guide, following by the TreVolo unit and Safety information brochure.

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BENQ TreVolo Front and Rear Views - Speakers Closed

BENQ TreVolo Front and Rear Views - Speakers Closed
BENQ TreVolo Front and Rear Views - Speakers Closed. Photo © Robert Silva - Licensed to

Shown on this page is a front and rear view of the BENQ TreVolo with the Electrostatic speaker panels closed.

On the left side is the front of the TreVolo, which shows the two woofers behind and unusually designed speaker grill.

On the right side is the rear of the TreVolo, which shows the Bluetooth source selection button (near the top), and the unit's physical connection options, which include (from left to right), AC Power Adapter Receptacle, Analog Audio Line Out (allows connection of the TreVolo to an external audio system), Line In (allows connection of external sources, such as CD/DVD/Blu-ray Disc players, many media streamers, and more...), USB input (allows access to content stored on USB devices, such as flash drives (requires USB-to-micro USB adapter).

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BENQ TreVolo Front View Speakers Open

BENQ TreVolo Front View Speakers Open
BENQ TreVolo Front View Speakers Open. Photo © Robert Silva - Licensed to

Shown above is a front view of the BENQ TreVolo with the Electrostatic speaker panels open.

The fold-out Electrostatic panels radiate the mid-range and high frequencies without the need for separate cone-type mid-range and tweeter speakers. However, Electrostatic speakers do not reproduce low frequencies well, so BENQ has placed two traditional (albeit compact) 2.5-inch cone woofers in the center body of the TreVolo, which can be seen through the uniquely designed speaker grill.

In addition, to further enhance low-frequency sound, there are also two passive radiators located on each side of the center body which is not visible in this photo.

NOTE: The TreVolo can work with the Electrostatic Speakers folded in, but the sound will be muffled in lower frequencies due to the obstruction of the passive radiators.

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BENQ TreVolo Side Views Speakers Open - Passive Radiators

BENQ TreVolo Side Views Speakers Open - Passive Radiators
BENQ TreVolo Side Views Speakers Open - Passive Radiators. Photo © Robert Silva - Licensed to

Here are two side views of the TreVolo, with the Electrostatic speaker panels open, which also reveals the two Passive Radiators mentioned on the previous page.

The passive radiators are designed to enhance the low-frequency output generated by the two woofers.​

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BENQ TreVolo Top View - Onboard Controls

BENQ TreVolo Top View - Onboard Controls
BENQ TreVolo Top View - Showing Onboard Controls. Photo © Robert Silva - Licensed to

This photo presents a look at the top view of the BENQ TreVolo, which shows the onboard control functions.

Starting near the back of the top of TreVolo is the Power/Standby Button.

Moving forward there is Play/Pause button (for physically connected devices), which also doubles as the speakerphone button (the TreVolo has a built-in microphone).

Moving to the of the Play/Pause button is the Ambiance Mode Button, which provides the following options:

  • Pure (Indicator light surrounding the Mode button turns green) - You hear the sound as it is provided by the source.
  • Warm (Indicator light surrounding the Mode button turns red) - Puts more emphasis on Bass frequencies.
  • Vivid (Indicator light surrounding the Mode button turns blue) – Emphasizes the mid-range.

Finally, near the top front of the TreVolo, are the onboard volume controls.

NOTE: The BENQ TreVolo does not come packaged with a separate remote control, but you can control the functions of the TreVolo using a free downloadable iOS/Android App, which will be illustrated and discussed at the end of this review.

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BENQ TreVolo Control App and Review Summary

BENQ TreVolo Remote Control App
BENQ TreVolo Remote Control App. Photo © Robert Silva - Licensed to

In addition to onboard controls provided on the TreVolo, you also have the option of controlling the TreVolo's functions via the BENQ Audio App for compatible iOS and Android devices. The example of the App interface is shown in the above as it appears on an HTC One M8 Harman Kardon Edition Android Phone.

As you can see, you can view the battery power status (if you are running off the AC Adapter, the status will always show 100%), control the Ambiance/EQ settings, as well access the illustrated user manual.

Review Summary

Now that you have gotten a complete look at the features of the BENQ TreVolo, here are my thoughts on its performance.

What I Liked

  • Innovative design: I really liked the overall look of the unit with its slim out-of-box compact profile "expands" via fold out thin Electrostatic Speaker panels.
  • Innovative use of Electrostatic speaker technology: In addition to the innovative design, on the technical side what makes this system standout is the incorporation of speaker technology that, up to this point, has been reserved for very high-end speaker applications.
  • Can run on AC or provided rechargeable battery (up to 12 hours of battery time): The TreVolo can easily be moved from room-to-room or taken outdoors (it is not weatherproof though so be cautious).
  • Good overall sound quality: Although I did not have the same "blow-your-socks-off" listening experience I had when I listened to the TreVolo in its controlled demo setup at the 2015 CES, in my real-world home environment, I was pleased with the result with one caveat (refer to the first item the next section below).

What I Didn't Like

  • Vivid setting can make highs sound brittle: The TreVolo provides three Ambiance/EQ modes that provide practical listening options. However, one setting that had both some good and bad effects for me was the Vivid setting. This setting does a good job of bringing more emphasis to vocals, as well as instruments, which is very practical, but I also found that on some CD-based content, it also had a tendency to make the higher frequencies sound brittle. As a result, I feel that the Vivid setting is best used at lower volume settings.
  • Very narrow stereo sound field: Even though the fold-out Electrostatic speaker panels add physical width to the sound field, the compact nature of the TreVolo means that the actual stereo sound field is narrow, which, for a stereo or home theater listening application, doesn't quite cut it. However, the TreVolo does feature an analog stereo line output, if you want to use it as a source device for listening to music on a larger stereo or home theater setup.
  • Micro-USB adapter plug/cable not provided. I was all set to plug my USB flash drives into the TreVolo to listen to some tunes, but I had to get a USB-to-Micro USB adapter (see examples and check prices. It would have been nice if one was just included in the TreVolo package - or just incorporate a more commonly used standard USB port.
  • No Remote Control provided - must use compatible iOS or Android (free app download provided) - or use onboard controls. It is important to not that TreVolo is designed to be used with a Smartphone for both music listening and control. However, when listening to other sources (such as USB, portable plug player, or even a CD player), it would have been nice to have an option to use a standard remote control.

Final Take

Although the BENQ TreVolo is not the typical home theater product I review, it is definitely an innovative audio product that can provide a supplementary music listening experience around the house - Just fold in the speakers and carry to any room - ​if you aren't near an AC plug - the batteries (if fully charged) will last up to 12 hours. Also, If you are looking for a compact Bluetooth audio system that is a step up from the usual Bluetooth speaker fare that is cluttering up store shelves these days, it is definitely worth checking out.

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