With such large drivers, it's no surprise that Sony bundles a small headphone amplifier in the box. This small black box is very simple with a single 3.5mm mini-jack socket that the headphones plug into. The cable at the other end of the amp plugs into your source device, and a sliding power switch activates and deactivates the unit. The amp is powered by two AAA batteries and it's still going strong after a week of heavy use. You can drive the PFR-V1s without the amp if your source has enough grunt - this is confirmed by the fact that a very long extension cable and a 3.5mm to 1/4in adapter are included, allowing you to plug into a proper hi-fi amplifier.
Sony's Personal Field Speaker moniker is borne out by the way the sound is delivered to your ears. It's hard to describe, but it simply doesn't sound as if you're listening to headphones. Instead the music seems to flow all around your head, as if you were sitting in the sweet spot of a custom built listening room with a high-end hi-fi and speaker setup. Despite the drivers being a few centimetres from your ears, the PFR-V1s manage to block out the vast majority of ambient noise, without the need to pump the volume up to ear bleeding levels. Talking of volume levels, these headphone can achieve seriously high output levels, without any distortion - put it this way, they're likely to cause you physical damage before they exhibit any sign of sound degradation.
The PFR-V1s produce a remarkable level of clarity that's complemented perfectly by the bass, which is injected directly into your ears. Every instrument and nuance of music is clearly discernable, but without the loss of cohesion that can often afflict multi-driver headphones. It also doesn't seem to matter what style of music you throw at the PFR-V1s, they simply excelled with every genre I pumped through them.
I kicked off my listening with Rockferry, the outstanding debut album from Duffy, and the PFR-V1s highlighted just how much of a vocal talent this girl is. No matter what track I listened to, Duffy's simply beautiful voice flowed through my head with a silky softness. In particular I'm Scared exhibited the impressive versatility of these headphones, with the gentle tambourine clearly heard, despite being a way behind the vocals in the mix. As the verses melt into the chorus, the percussion and string accompaniment meld perfectly with the rest of the arrangement without distracting from the vocal focus.
Changing style completely I fired up the classic Smashing Pumpkins disc, Siamese Dream. The opening track, Cherub Rock is a favourite of mine - something that I was reminded of last year when we were playing too much Guitar Hero III in the office. Not only is Cherub Rock a superb rock anthem, it's also a very tough audition for headphones. It could be said that the band went over the top with the effects pedals on this track, although it's that dirty sound that gives the song its persona. The result is that some headphones will overpower the vocals with the guitars, or even turn the riffs into a distorted mess. The PFR-V1s didn't miss a beat though, and the only time I've heard the song sound better was when the band were on stage in front of me.