Find a decent fit with the RHA SA-500 and you'll be rewarded with good sound quality. Bass is big and well-behaved, providing the headphones with a warm and powerful sound.
For optimum low-end response though, the ear cups need to maintain a decent seal with your ear. After fiddling for a while, we found this was still improved by man-handling the cups over the ears. When in a quiet environment, this isn't a problem as loss of sound quality is largely because of intrusions of external noise, but it limits their effectiveness on noisy public transport, compared to on-ear alternatives like the AKG Q460 and Sennheiser HD 218.
Again comparing the headphones to the Sennheiser HD series - probably the RHA SA-500's closest rival - the treble here lacks a little resolution and finesse. It's not harsh or sibilant, but worth consideration if you're after a more chilled-out, refined sound rather than the bassy fun of the SA-500. As the saying goes, you pay your money and take your choice.
Aside from our (admittedly significant) comfort issues, the RHA SA-500 are well-made headphones. The problem they face is that several of the most popular on-ear headphones of all time are available at a similar price. The Koss PortaPro, Sennheiser PX100 and HD 218 can all be bought for under £30, and in our experience at least they are more comfortable sets. The RHA set can compete on sound thanks to its exciting bass, but comfort means a lot when it's a core part of the headphone experience - as important as sound when it goes wrong.
With powerful bass, a removable cable and an attractive design, the RHA SA-500 sound like headphones to be reckoned with. Sadly, we found them rather uncomfortable to wear compared with the opposition. We can bear a little discomfort for sound quality, but when it affects the sound too - by lessening the seal with your ear - we can't let it slide.