PSB Alpha VS21 VisionSound Base - Review

PSB Alpha VS21 VisionSound Base - Front, Rear, and Bottom Views
PSB Alpha VS21 VisionSound Base - Front, Rear, and Bottom Views. Photo © Robert Silva - Licensed to

Sound Bars and Under-TV audio systems are very popular these days, and it seems that everyone is getting into the act, even high-end speaker makers. Continuing with this trend, PSB has jumped in with their Alpha VS21 VisionSound under-TV audio system that it hopes will find a good home with consumers.

Product Overview

To start, here are the features and specifications of the PSB Alpha VS21 VisionSound Base.

1. Design: Bass reflex single cabinet design with left and right channel speakers, two down firing woofers, and two rear mounted ports for extended bass response.

2. Main Speakers: One 2-inch cone midrange and one 1-inch soft dome tweeter for each left and right channel.

3. Woofers: Two 4-inch down firing woofers additionally supported by two rear-mounted ports.

4. Frequency Response (total system): 55Hz - 23,000 kHz + or - 3dB (on axis), 55Hz - 10,000kHz (30 degrees off-axis).

6. Amplifier Power Output (total system): 102 watts (Each of the six speakers is individually amplified by a 17-watt amplifier)

7. Audio Decoding: Accepts Dolby Digital Bitstream audio, uncompressed two-channel PCM, analog stereo, and compatible Bluetooth audio formats.

8. Audio Processing: PSB WideSound Virtual Surround Sound Processing.

9. Audio Inputs: One digital optical One digital coaxial, and One analog stereo input set. Wireless Bluetooth connectivity is also included.

10. Audio Outputs: One Subwoofer line output.

11. Control: Control via Wireless remote only. Also compatible with many universal remotes and some TV remotes.

12. Dimensions (WHD): 21 3/8 x 3 3/8 x13 inches.

13. Weight: 12.3 lbs.

14. TV Support: Can accommodate LCD, Plasma, and OLED TVs with maximum 88-pound weight (as long as the TV stand is not larger than the VisionSound Base cabinet dimensions). Also, if you have a small-to-medium-sized video projector, you can use the VS21 as a compact audio system for your projector - For more details, read my article: How To Use A Video Projector With An Under-TV Audio System.


For audio testing, the Blu-ray/DVD player I used (OPPO BDP-103) was connected directly to the TV via HDMI outputs for video, and digital optical, digital coaxial, and RCA stereo analog outputs were alternately connected from the players to the PSB Alpha VS21 VisionSound Base for audio

To make sure that the reinforced rack I placed the VisionSound Base on was not affecting the sound coming from the unit, I ran a "Buzz and Rattle" test using the audio test portion of the Digital Video Essentials Test Disc. I did not hear any rattling when the VS21 was standing alone - However, when a TV is placed on top of it, some rattling can be heard from the TV frame at louder volumes.

In listening tests conducted with the same content using the digital optical/coaxial and analog stereo input options, the VisionSound Base provided very good sound quality.


The PSB Alpha VS21 VisionSound Base did a good job with both movie content, providing a well-centered anchor for dialog. I liked the provision of both a dialog enhancement setting, as well as being able to further enhanced dialog within the virtual surround environment via the WideSound Plus setting option.

For CDs or other music source listening, the PSB doesn't offer a very good straight two channel mode - but just as with movie listening, you can emphasize the center vocals further via the Dialog setting option. Also, if you wish to expand the two-channel sound field into a more "surround sound" type music listening experience, you can also activate the WideSound and WideSound plus options, just as you can for movies...

Using the audio tests provided on the Digital Video Essentials Test Disc, I observed a listenable low point between 40Hz to a high point of at least 15kHz (my hearing gives out at about that point). However, there is audible low-frequency sound as low as 38Hz. Bass output is strongest at about 60Hz with a fairly smooth output from that point until it transitions to the midrange.

On the one hand, the bass response of the VS21 is not overly boomy, but the downside it is that it can be too subtle, especially on movie content with deep low-frequency effects. Also, there are no bass or treble controls, or separate woofer level control, so you can't bring out the bass further in relation to the left and right channels that is already engineered in.

However, one thing to point out is that PSB Alpha VS21 VisionSound Base does provide the option of connecting an optional external subwoofer of your choice, which is of great benefit for movie listening.

Using an external subwoofer with the VS21 is a two-step process. First, you connect the subwoofer line output of the VS21 to your subwoofer, then, using the remote, you turn on the SUB OUT feature which activates an 80Hz crossover between the VS21 and the external subwoofer. What this does is divert all audio frequencies below 80Hz to the external subwoofer, with the VisionSound Base handling the rest. If you are not using an external subwoofer, make sure the SUB OUT is deactivated so that frequencies lower than 80Hz are handled by the VS21's own built-in woofers.

Any external powered subwoofer can be used, but one option suggested by PSB is its SubSeries 150 which features a compact design.

On the other hand, I found that the midrange and high frequencies were very good - dialog and vocals were clear and full-bodied, and the highs, although not "sparkly" were not overly bright or brittle - providing a very listenable experience for both music and movies.

With the THX Optimizer Disc (Blu-ray Edition), using the Dolby Digital bitstream setting, the PSB properly decoded the 5.1 channel signal placing the left, center, and right channels correctly, by folding the center, left, and right channel surround signals within the left and right speakers. This results in a physical 2.1 channel system but with a full Dolby Digital 5.1 channel signal present, combined with the Widesound settings, the VisionSound Base projects a sound field that projects beyond the VS21's physical cabinet.

With regards to audio decoding and processing, it is important to point out that although the VisionSound Base does provide Dolby Digital decoding, it does not accept or decode incoming native DTS-encoded. For DTS-only audio sources (some DVDs, Blu-ray Discs, and DTS-encoded CDs), you should set the digital audio output of the player to PCM if that setting is available - another alternative would be to connect the player to the VisionSound Base using analog stereo output option.

On the other hand, for Dolby Digital sources, you can simply switch the player's audio output settings back to bitstream if you are using digital audio connections between the player and VisionSound Base.

What I Liked

1. Good overall sound quality for the form factor and price.

2. Built-in Dolby Digital Decoding.

3. Wide soundstage when WideSound or WideSound Plus is engaged.

4. Good vocal and dialog presence.

5. Incorporation of wireless streaming from compatible Bluetooth playback devices.

6. Well-spaced and clearly labeled rear panel connections.

7. Very quick to setup and use.

8. Can be used either to enhance the TV audio listening experience or as a standalone stereo system for playing CDs or music files from Bluetooth devices.

What I didn't Like

1. No HDMI pass-through connections.

2. No onboard controls - Remote control required.

3. No DTS decoding capability.

4. No 3.5mm audio input connection option

5. No Bass, Treble, or manual equalization controls provided.

6. Platform size too small for many larger TVs.

7. Pricey, considering its small size and the need for an external subwoofer.​

Final Take

Incorporating a good sound system within the confines of an Under-TV audio system is definitely a challenge, and the PSB Alpha VS21 VisionSound Base has a narrow soundstage out of the box with very little sound projected beyond its left and right borders, which is fine for 2-channel stereo music listening. However, once you engage its WideSound virtual surround sound processing , or connect a Dolby Digital-encoded source, the sound stage does widen considerably, giving the listener the impression that sound is coming from the TV screen, and also provides a "wall of sound" across the front, and slightly to the sides, of the listening area.

While the PSB Alpha VS21 VisionSound Base provides a good alternative to a TV's built-in speakers, and also provides a good two-channel music listening experience, there is room for improvement in features (needs larger surface to accommodate larger TVs), performance (needs bass, treble, or manual equalization controls), and price (competition with similar products).

For a closer look and perspective, also check out my supplementary Photo Profile.