The HiFi power that is Lenbrook have slowly become more and more active in the portable audio scene utilising both the NAD and PSB brands they have at their disposal. Sometimes to my ears traditional HiFi companies attempts at our realm are a bit lack lustre but so far what we have seen with the previous PSB models (closed back headphones) and especially the NAD HP50 headphones I have already reviewed has been pretty good. While I have yet to listen to any of the Lenbrook  in ear monitors which until now have been under the NAD brand, this is by far the most interesting and appealing one to be released. Coming in both black and white the M4U 4 features a set of hybrid drivers (1 balanced armature and 1 dynamic driver) which for the last couple of years has been the most followed trend in IEM design. Where the Lenbrook models go further though is in the research into a frequency response curve which is optimal for headphones that they label Room Feel. Similar to the research Goldenears have done and the Olive Welti target this mainly focusses on what should be achieved in terms of low end gain to recreate the warmth heard in flat measuring speakers in your average listening room. Because when earphones are in our ears we don’t have the resonance and effects of a room to deal with and they are striving to recreate that feeling in earphones/headphones. Seems like a goal perhaps only a loudspeaker company could achieve, or L’Ear with their interesting NSS tech, but thats something for another day.


The M4U 4 has a price tag of £229 in the UK and Rich Stevenson, the nice PR guy who got these over to me was pleased to say that PSB received an Innovation award from CES for these. Personally I think thats good exposure but not an award to get bent up on. If any earphones deserved the innovation award based on their price tag it is what Dunu have been doing, they are miles ahead of the competition with their DN-2000J. I am generally not a big fan of these more commercialised awards but it may impress some of you, which i’m more than happy with.

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My Favourite Form Factor

I feel that now days if you want to make a higher end IEM that it just has to follow that over the ear universal custom form factor. You are right, it lacks innovation nowadays but it works. These follow that nicely with all the boxes ticked, including you guessed it, removable cables, something competition at this price still somehow lack. But PSB sadly decided they know better than to use any of the industry standard cable connectors and designed their own, groan. It is not a bad connector, like a MMCX with a smaller diameter but it is nowhere near the level of Jays proprietary design. More importantly you can’t find a single 3rd party cable brand that can build a cable with this connector. Fortunately they do include a spare cable with a mic and remote on it. You also get a nice case, Comply and silicone tips and some adapters for plane and 1/4 inch jacks.

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The build quality to me has been a little underwhelming from such an established brand. I am seeing products come from companies that have just had their products funded by Kickstarter 10x more polished than this and at cheaper price points. I mean the filter in the sound bore on one of my channels was on it side blocking it, I had to get tweezers and go all DIY on it before I even listened. Now while PSB do boast these being lightweight, which is indeed the case due to them being made of plastic, the finish is actually good. What is not is the way the seam is so visible with a gap all the way down the housing and a faceplate that looks so easy to pry off.

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The cable is less concerning to me and pretty standard affair. It is very thick on the bottom half and has a nice y-split with cable cinch. It doesn’t tangle much either and also lacks memory wire. The lack of memory wire combined by the lightweight does make these comfortable. They also have quite a long nozzle that is well angled for a very deep fit, deeper than competitors such as the Trinity Atlas (£149). Deep insertion obviously aids isolation which is also top notch.

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Sonny Trigg