Sennheiser IE 40 Pro review

The IE 40 Pro is the most affordable model in Sennheiser’s new pro in-ear monitoring range. 

With three models topping out at £500 for the IE 500 Pro, all three designs use single-wide band dynamic drivers, with a 10mm design in the IE 40 Pro and 7mm designs in the IE 400 Pro and IE 500 Pro. 

Many in-ear monitors use single or multiple balanced armature drivers, and both these and wide band dynamic drivers have their strengths and weaknesses. Nevertheless, one big advantage of a single broadband transducer is that it offers a wide frequency response and doesn’t require the crossovers found in multiple driver designs. 

The IE 40 Pro follows a reasonably established design path for in-ear monitors. The earpiece module itself incorporates a removable tip and the box includes four pairs - three silicone and one foam. These vary in size, allowing you to achieve a reasonably sealed fit, vital for both frequency response (particularly the bass end) and isolation from surrounding noise. On some in-ear designs we’ve tried, the tips have proven hard to fit or remove. Thankfully, this is not so with the IE 40 Pro, and auditioning different sizes proved reasonably straightforward. 

The small section of cable into the earpiece is thick and stiff. This lets you mould the cable round your ear, keeping it out of the way and helping hold the earpiece in place. The earpiece connects to the wire via a push/pull detachable plug and this also rotates, which helps take the strain off the wire and plug when you adjust the earpiece positioning. Finally, the IE 40 Pro comes with a pocket-sized storage pouch, a small cleaning tool, 6.3mm jack converter and either black or clear finish. 

Sonically, the IE 40 Pro sounds reasonably natural, with good articulation in the high frequencies and a full but not overpowering low end. We did find them a tad too bright in the top end at higher volumes, but this isn’t a deal killer. Either way, they do sound considerably better than standard earbuds, making them a decent multipurpose purchase. 

Also rather positive is the comfort and fit. With a medium-sized in-ear module and quickly replaceable tips we quickly achieved a decent fit - important if you’ll be wearing them for long stretches. In fact, we’d say these are some of the most  comfortable off-the-shelf in-ear monitors we’ve tried; impressive given the modest price tag. The only real gripe we have is the rather short lead (1.3m) and lack of lead extender. 

We really like the IE 40 Pro in-ear monitors. They deliver decent sonics without costing silly money, and suit live use as well as general playback duties. The only real gripe is the short cable and lack of extender, but, all told, these would make a wise buy for either live, monitor or simply everyday listening duties.