Shure's SE420 earphones sit below the company's flagshipmodel. They also sit in an awkward spot for potential buyers: "Do I buy these or wait a few weeks and buy the top model?" It's a fair consideration, but consider this: maybe you don't even need the top model. Could you save yourself £100 and still get almost the same performance?
As canalphones, these need stuffing well into your ear to work properly. While a little tricky at first, they're a professionally fitting pair of 'phones and come with a premium fit kit to ensure snugness. The sound-isolation relies on a good seal between the earphone and the ear canal, so getting used to the unusual fit is paramount. Three different-sized pieces of foam, along with silicon flange tip options, are included. The best performance is suggested to come from using the flange tips, but our tests yielded excellent, better results from using the foam. A healthy bit of experimentation is advised if you're undecided.
While sound-isolation won't do anything about the deep rumble of a train or aeroplane (you'll want noise-cancelling headphones for that) it successfully deadened the vast majority of ambient noise in our office, such as talking, keyboards and the air conditioning system. It also silenced a screaming child on the Tube -- something we appreciate as much as oxygen and shoes.
Sound quality is generally very good, thanks to twin drivers in each 'phone: one woofer, one tweeter. A crossover is employed to direct the correct frequencies to the correct drivers. Lows, mids and highs are well balanced, but booming bass and crystal-clear highs are, perhaps fairly, compromised a little too much compared to the model above.
Some powerful drum and bass from Pendulum shook the woofer considerably, though it's a much rawer bass than the beautifully tuned bass ofs. Conversely, Dire Straits' Brothers In Arms was very clear, but we felt competing models have done better in terms of pristine clarity for a similar price.