Roberts Zen Plus – Innovation in Bedside Radio

The Zen Plus concept was to create a small and attractive clock radio with some distinctive features:

  • Sleep sounds – The device needed to have a library of sleep sounds built in
  • Excellent sound – The sonic experience should be class leading
  • Attractive – The unit should be extremely compact and attractive
  • Sustainable – The unit should feature sustainable materials and no plastics in packaging.

…And, the whole project needed completing in less than 1 year – from concept to in the shop for purchase.

Sleep Sounds

The solution arrived upon for sleep sounds was an inbuilt micro-SD card reader which would hold a number of pre-recorded sounds. The solution was not immediately straightforward since the Zen Plus could only feature minimal component count, and media playback is not a normal feature for a bedside radio. The solution employed was successful but involved some detailed software design – to use a media player / audio amplifier solution and to custom program all the bedside radio functions. I.e. the Zen Plus is not a bedside radio with sleep sounds, rather it is a Sleep sound media player with a bedside radio software component.

Excellent Sound

A personal hate of mine is the tinny sound of a low cost bedside radio. The Zen Plus needed to have a depth of tone which from a small enclosure suggests the use of a passive radiator as well as extensive use of DSP and limiting. The Zen Plus has all of these things, and features a very unusual acoustic solution of a ‘speaker within a speaker’ that houses the driver and passive radiator components and ensures a perfect air-seal. The amplifier processor device was carefully selected to support multiband limiting and a soft and smooth sounding EQ profile. The result is a radio that sounds gorgeous.


Tris Thornhill as a designer has the most remarkable attention to detail and explored several design concepts fully. The concern at the time was that the globe look is the most practical and acceptable look, but there are also several smart speakers that are globes that may cause confusion or even derision of our product. The solution was the ‘sunken’ appearance and flat front that affords a comfortable screen viewing angle and User experience, whilst making the product distinct from regular smart speakers… nice one Tris!


Several innovations made this product the most sustainable Roberts product at its launch. The use of a QR code eliminated the need for more than a basic quick-start guide in the box. The packaging was extremely sustainable, and the product itself featured drop-in recycled plastics.


The Zen Plus was not ‘easy’ in any sense. The brief was ambitious. It required a rethink of many traditions in approach and a huge amount of ‘above and beyond’ from the team. However, when complete, the product shone for this extra effort.