Portable is a vague term applied to headphones. Clearly even the chunkiest models are portable if you've got a big enough bag handy, while many would baulk at carrying anything bigger than an in-ear model.

The new Audio-Technica ATH-ES10 isn't quite pocket-sized, but it's small enough to fit in a small briefcase or handbag; with the earpieces rotated it's about 25mm-thick.

We've spotted plenty of cool dudes wearing similar-size models on the street, and for the audiophile (or indeed audio professional) on the move, maybe expecting to spend quite a lot of time in trains, planes and hotels, it looks a practical proposition.

Must-have 53mm drivers

The big news on the audio front is that this model includes A-T's latest 53mm drive unit, not bad given each earpiece is only 75mm diameter on the outside. As we've noted before, 53mm is the current 'must-have' size and A-T developed this unit for high-end duty.

In this case it's housed in a closed-back surround made of titanium, with soft-leather padding which rests mostly on the ear, making this strictly a supra-aural design, though it's really betwixt and between that and circumaural.

The headband is similarly padded and that, plus the light weight, makes this a comfortable headphone, although the rather tight fit can lead to hot ears in warm weather.

Likes to go loud

The tight fit does ensure good isolation from the outside and if this doesn't quite give Etymotic-like sensory deprivation, it certainly does mitigate the annoyance of noisy surroundings.

Against that, we should report that the lead (which is very flexible) still transmits quite a lot of friction noise to the ears. Sensitivity is quite high and the moderate impedance is well judged to give ease of drive (hence good sound), but still plenty of volume from portable devices.

If A-T's numbers are to be believed, the maximum output is just about enough to blow your ears out – we didn't experiment!

Flip side

What this headphone does well, it does very well indeed. As luck would have it, we tried it out first on some well-produced classic rock and it gave a cracking performance.

The bass is just a little lifted compared with what we regard as neutrality, but only a little and the rest of the frequency range seems well balanced. At the same time, there's a really superb sense of rhythm and loads of detail, which all adds up to a highly convincing and persuasive performance.

The other side of the coin was shown by a familiar test recording of classical voice and piano. This was much less successful, both voice and instrument sounds coloured, with a synthetic quality to the piano, an uncomfortable imbalance between consonants and vowels from the singer and a general feeling that detail is blurred.

High-octane

Clearly if a reproducer sounds coloured with any one kind of sound it really is coloured, but the crucial consideration is how much that coloration affects any particular track one is listening to. It just happens that solo piano and relatively ambient male voice are the very worst things for this headphone, but with most recordings it sounds much more natural.

A couple of large-scale orchestral recordings proved that it's got nothing against classical music as such and its imaging is unusually good. These discs have plenty of detail which came through well and it was possible to hear some slight tonal balance anomalies, but nothing serious.

Clearly, the natural home of the ES10 is high-octane rock, jazz, pop and similar. It is one of those components that puts in such an energetic performance that minor blemishes in areas like tonality simply cease to matter.

With more laid-back sounds one gets used to the tone quality and sound seems to improve after a few minutes, but the right sort of music brings on a satisfied grin at the outset and total satisfaction.

Follow TechRadar Reviews on Twitter: http://twitter.com/techradarreview