The staid, boxy personal computer (PC) is giving way to unconventional designs like a cylindrical speaker or a backpack as PC makers strive to stem a prolonged decline in global sales.

PC vendors HP, Lenovo, Samsung and MSI are leading the charge, having recently shown off new designs to fend off rising competition from mobile gadgets such as smartphones and wearables.

At Berlin's IFA 2016 consumer tech show in September, HP unveiled its Pavilion Wave, a cylindrical speaker-like computer that responds to voice commands, to better target home users. HP also unveiled its Elite Slice, which can be customised by snapping on stackable modules with different features, targeted at businesses.

Last month, Samsung launched in the United States its ArtPC Pulse cylindrical PC with an omni-directional speaker.

Meanwhile, Lenovo came up with its Ideacentre 610S Home PC, an entertainment hub with an optional, detachable projector. And MSI unveiled its VR One backpack PC for virtual reality (VR) gamers.

Gartner analyst Tracy Tsai said the redesign is aimed at stemming the decline in consumer desktop PC sales. "General-purpose computers are not selling, as users are happy with smartphones, and see no need for a PC," she said.

The market research firm reported that global PC shipments declined by 5.7 per cent in the third quarter of this year compared with the same period last year. It is the eighth consecutive quarter of PC shipment decline, the longest ever.

Ms Tsai said that users are no longer refreshing their PCs as often as the PC is no longer the primary device for getting onto the Internet.

For businesses, many applications and storage have moved to the cloud, so users need not upgrade their PCs for faster performance and better storage.

"A new and better customer experience is the only way to get them to part with their money now," said Ms Tsai.

Ms Anneliese Olson, general manager (personal systems) at HP Asia Pacific & Japan, said that the company had to think out of the box.

"We draw inspiration from fashion and furniture design," she said.

For instance, the Pavilion Wave's built-in speaker and microphone makes it look more like a piece of furniture than a gadget. It is designed to be a home entertainment centre as users are consuming more media through their home computing devices.

Backpack PCs such as the MSI VR One, which was officially announced at the Tokyo Games Show in September, are designed to be self-contained backpack computers that can be used to power and connect with VR headsets during game play. Its angular outlines give it a Transformer look.

HP also has its own Omen X VR backpack targeted at VR developers.

It remains to be seen if consumers will bite. One PC enthusiast, Mr Lim De Yang, said he prefers to build his own machine.

"As a power user, I prefer to configure my own PC," he said.

• The Straits Times reviews the HP Pavilion Wave and HP Elite Slice
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• HP's Elite Slice is a truly modular business PC