Tension Labs EAP03 Earphone Audio Processor Review - Tension Labs EAP03 Earphone Audio Processor Review


Here’s where things get clever. You see, the guys at Tension Labs care about your hearing. Now, we all know that cheap earbuds are bad for your ears – you have to whack the volume up to unsafe levels just to get a decent sound above background noise – but there are dangers even with high quality IEMs. that’s because a) there’s less distortion at higher volumes (encouraging louder listening) and b) many of us tend to like the sound we get at higher levels; even audiophiles risk putting their ears at risk.

The EAP03 helps you keep a lid on this. By default, it uses the sensitivity and amp gain data provided with an analysis of the volume signal running through to give you an accurate idea of the actual output hitting your eardrums in dB. What’s more, you can change the display setting to tell you how long you can safely listen to the current output without posing a danger to your ears. I know it’s a little bit nanny-ish, but at least it makes you think twice. Meanwhile, a little signal bar at the bottom shows you when you’re pushing your headphones too far and you’re in danger of clipping. When the bar goes too far, just dial down the volume and you ensure that you’re getting the optimal sound.

And that isn’t all the EAP03 can do. First, there’s a switchable 3DX soundfield expansion mode, designed to replicate the more open sound you might get with a pair of stereo speakers by crossfeeding some of the sound destined for the left ear to the right, and visa versa. Secondly, there’s a three-band parametric equaliser, where you can customise both the frequency for the low, high and mid EQs and also the gain levels applicable. Thirdly, the EAP03 has a built in mic, allowing you to both measure the level of background noise in your environment and – more usefully – feed the ambient noise into your headphone input. Imagine you’re on the train or in-flight and the guard/flight attendant shows up. There’s no need to drag your IEMs from your ears so you can hear them – just press the MIC button on the EAP03 and you’re away.

Of course, none of this would matter if the EAP03 dished out a mediocre sound, but it’s actually a very capable little amp. There are, however, some caveats. For one thing, the EAP03 is designed to be used with a headphone output, not an iPod line-out dock connector. While you can use the Amp Gain function to set the volume levels, you’re supposed to use the volume controls on your player. In practice, I got a better sound using a line-out dock and adjusting the Amp Gain to suit, but this means the dB readings on the EAP03 become inaccurate, while you need to visit the settings every time you want to change the volume. Secondly, the EAP03 isn’t designed to power demanding, high impedance, full-sized headphones.

The Earphone Sensitivity setting only goes down as far as 100dB/V, and you’ll need to push the Amp Gain quite hard to get a good sound from, say, the BeyerDynamic DT770 Pros or AKG K701s.In point of fact, I could get a very respectable sound from the DT770 Pros I have here, but if you want something to run full-sized phones efficiently, you might want to look elsewhere.

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