Performance

The earphones were burned in for 100 hours before they were tested. The earphones were used primarily out of an iPhone 4, but were also tested on the following rigs: iPhone 4 into a Fostex HP-P1, Head-Direct HiFiMAN HM-801 (both via headphone out and with a RSA Protector hooked up to the line-out).

Despite having two dynamic drivers the A03s are quite easy to drive. At about 50% volume on an iPhone 4 you will get plenty of volume. Besides being easy to drive the A03s also provide you with a neat little remote control that allows you to control volume and pause / play, and take a call if used with a compatible phone.

Due to the use of two dynamic drivers the headphones are capable of delivering a quite convincing low end response. The bass extension is very good and definitely on par with the MP4Nation Brainwavz M2 we tested a while ago. The bass is not overpowering but definitely invades the lower mids to an extent which gives them a slightly congested sound. Definition wise the A03s lack a little compared to the M2s especially when it comes to the lowest notes which sound a bit soft on the A03s. If the A03's bass had been a tad faster it would have sounded seriously good.

Midrange wise the RedGiant A03 in-ears perform well considering the shear amount of bass they are able to produce. The midrange is warm and slightly pushed back in the mix due to the big bass. Detail wise they are not up to much, but their forgiving nature is perhaps a pro when listening to the ill mastered recordings of today. The upper midrange is controlled nicely and the A03s exhibit almost no sibilance.

The treble has enough sparkle to give these earphones a little edge. While the treble is toned down somewhat it still has enough presence for most types of music. Given the U-shaped frequency response of the earphones they are surprisingly well sounding.