It would be foolish to spend upwards of £100 on an MP3 player and then not bother to upgrade the headphones, and when you do there's a raft of companies vying for your money. Sennheiser has always been strong on the budget headphones front and its latest CX400s - the follow-up to the incredibly...

The headphones come into their own where you can plug straight into an existing handsfree or remote control unit

Mobile phone headset upgrade potential; Good sound; Carry case

Bass not so good; Cable options can be inconvenient

As long as you don’t find their treble response puts your teeth on edge too badly, there’s really no reason not to give them thorough consideration.

Wide-open; lavishly detailed and informative sound; Fine touch- and app-control; More comfortable than they look

Don’t really look or feel the money’s-worth; Periodically spiky treble; Humdrum battery life

My time using the CX 400BT was very enjoyable. I appreciated all the customizable options and warm sound signature, as well as their flawless connection and accessibility. For $199.95 this is a solid true wireless from Sennheiser, and a sure buy if you’re looking for a reliable pair.

They’re not the most glamorous nor the most distinctive – but Sennheiser’s new CX400BT true wireless earbuds have it where it counts. They sound open and articulate, and if there’s detail in a recording to be extracted, you can rely on them to do just that.

Widescreen; detailed; and quite upfront sound; More comfortable to wear than they look; Great app and good touch-control

Can be excitable with treble sounds; Ordinary battery life; Don’t quite look or feel the asking price

“The sound is incredible, but the cost of a lowered price is a bunch of missing features.”

Superb sound quality; Responsive and customizable controls; Highly adjustable onboard EQ

Lacks features for the money; Possible fit and comfort problems

Sennheiser has a reputation for top-quality sound, and both the Momentum True Wireless and its sequel, the Momentum 2 True Wireless, scored very highly on sound quality when we reviewed them. But along with that excellent sound comes a fairly steep price — $300 is what you’ll pay for these earbuds. Clearly, that eliminates a lot of potential buyers. So the challenge for Sennheiser was to create a set of true wireless earbuds that cost less without sacrificing the biggest reason for buying them in the first place: High-quality sound. Its answer to that challenge is the $200 CX 400BT True Wireless. Their price is definitely more palatable, but do their overall feature set and performance make them a worthwhile investment when you consider how many other excellent earbuds can be had for the same, or similar, money? Let’s take a look. The CX 400BT’s relatively plain cardboard box contains the earbuds, their charging case, a set of four sizes of silicone eartips (large, medium, small, and e...

Superb sound quality; Responsive and customizable controls; Highly adjustable onboard EQ;

Lacks features for the money; Possible fit and comfort problems;

The Sennheiser CX 400BT True Wireless earbuds have an understated design but pack 7mm full range dynamic drivers for the detailed and wide sound that belies its modest looks. Add in a light build and comfy ear tips for comfortable extended wear when working from home or on the go and you have an...

Sennheiser’s first true wireless headphones outside the Momentum range offer the same superb sound quality without such a steep price tag

Superb sound quality; Stable connection; Quick; seamless pairing

No splash proofing; No ANC; Not cheap

Sennheiser want to demonstrate that — in addition to their excellent Momentum True Wireless , which are right at the top of the charts both in terms of hit lists and price — they are quite capable of catering to the upper mid-range of the market.