Tune Me Up

Until this point the BD4.2 is a pretty unique product from internal design to construction materials, but, it does like to follow the current trend of a tuning method. No prizes for guessing what is adjustable either, of course it is the bass response. It is done via a little pot on the side of the housing next to a vent. With it not being stepped there is just a basic marker to help you match adjustments on both channels and I have to say it is kinda fiddly. At this point I don’t know if I prefer actually changing filters or adjusting a pot, both are annoying to some extent.


The tuning knob actually has a lot of versatility to give it its due. It starts at 8 o’clock for minimal bass and goes all the way round to 4 o’clock for maximum power, with 12 obviously being the middle ground. Lear recommend the following:

Studio monitor reference sound: 8~12 O’clock
Pop and general taste : 12~3 O’clock
Solid Deep and powerful bass: 3~4 O’clock


Now I have course taken some measurements and these help us get a much more accurate look at what is going on with this dial. Blue is at 4, red at 12 and yellow 8!

164.2 Bass Range

As you can see the red curves (12 o’clock) is pretty much the middle ground being a perfectly flat frequency response from 1kHz to 20Hz. Turning the pot down actually just removes bass and of course turning it up does just that. Now the total range of bass it has is just humongous! At 20Hz there is no less than 27dB variation and at a 100Hz we still have 20dB. That is just INSANE!!! From 12 o’clock towards 4 o’clock boosting takes effect from as early as 600Hz whereas the reduction down to 8 o’clock starts a bit later at 300Hz. It is also worth noting that from 8-12 you have pretty much the same FR from 300Hz onwards whereas when you start adding the bass past 12 you are also getting a 5dB reduction at 1.5kHz that stays to about 8kHz, if intentional that is interesting because it makes the signature of this chaotic in terms of bass!

How Does this Sound on the Ears?

With such a range on the bass response this is a bit of a chameleon in terms of pin pointing just one specific sound signature. It does a much better job at changing overall sound than say something like JH Audio’s Roxanne which is still boosted in bass and warm/thick sounding on the lowest bass setting. This can be skinny with a tiny bottom and in the same breath can it manage as much of a bass whollop as you can even possibly fathom. That of course makes this section very difficult to go about, especially to stop things getting too ambiguous.

Now on arrival, before I had even given time to measuring the differences the bass pot made I had a little play with the included screwdriver to see where I wanted to do most of my listening. Roughly half way, 12 o’clock, seemed to be the sweet spot for me and gave the most versatile listen. Thats not to say when I would be listening and something like Chase and Status come on and I was like “I NEED MORE BASS”! 2 minutes later and I am listening to the same track with kick drums thumping my cranium and synths rumbling my eye balls. I really do have to give it up to the 100% bass setting due to just how controlled the bass still is. Low mids retain identification and decay isn’t even too overcooked, it just a lot of pressure being unloaded on your ears.

Truthfully the bass at around 70% is offering an amount of elevation that still provides quite the kick  some self confessed low end lovers crave without being as well, straight up mad as 100%! My next point would be that I think the majority of users will end up somewhere between 40% and 70% of the bass, depending on preferences and music tastes. Take the lowest bass setting for example, it becomes a precision tool, maybe useful in studios but I don’t even think it would be applicable to that trade through such a weak and fast bass, with no definition or weight. 40% is were things start to heat up but stay a touch on the lean side and by 50% we are very natural and honest and thats were I have chosen to stick.


50% is the Marker

Now that we have a point of reference to move on from lets start to talk a bit more technically about Lear’s top dog. My first point would be what a savage it is. This is a monitor that just doesn’t take any shit. It is ruthless and not simply because it is super fast or this bright and analytical tuned tool. The BD4.2 tears apart bad recordings, more so than anything I have ever listened to that is tuned similar. The Last Shadow Puppets were simply unlistenable for example. A shame because I was preparing to go see them in Alexandra Palace as I wrote this!

My second would be how smartly it has been made in all elements. For a long time I have questioned the design of high end IEMs. While headphone drivers are purpose built to be used with amplifiers, IEMs remain willing to draw hiss out of even the weakest of portable outputs. The LCM-5 was one of my worst ever offenders and hopefully what swayed Lear into putting more thought into drivability this time around. Sorry if I am being cryptic but what I am getting at is this needs some juice, and I love that, it doesn’t hiss and I don’t struggle getting a black background! This seems to be an incoming trend as a new 10 driver universal soon to be released is 166 ohms, also made for portable amp use!

Back to the actual sound at with my preference of bass at halfway the contrast between all frequencies is minimal. Bass and treble see eye to eye and the midrange are balanced perfectly in-between. Just how I like it.

While the bass is captivating, diverse and deep, I have not found it to ever have the most genuine of layering and textures. It’s great bass, rhythmic and pulsing to a point where your ears prick up to listen, but I don’t listen and think this is what it would be like to be in the room with Phil Lynott or Jack Bruce. I don’t know why either because breaking it down it has everything, lots of information down low, good pace and honest levels of quantity.

The midrange is a dryer affair, giving you the truth, however ugly… or beautiful it may be! I find there to be some extra energy in the upper mids, giving some lovely clarity and extra zip to the sound but carefully done without taking anything away from rest of the midrange, say the tonally correct male vocals. The overall feel of the midrange is an area that gets small changes depending on switches, it feels a bit thinner with less bass and gets shrouded in the slightest when bass moves into overdrive. In my favourite setting it well weighted in terms of body and as I have said before, just there in the music, as is everything. While there is good clarity, separation and everything seems without a toe out of line, this never becomes that musical midrange that has me gushing. great quality? No doubt, but magical no.

I think when a monitor doesn’t immediately give me something to write about it must be doing something pretty well because flaws jump out quicker than anything and the treble here is pretty nondescript. 5kHz seems a bit strong providing some flare but after that the high frequencies are straight forward, clean and accurate. They don’t come across bright or over accentuated but are certainly not dumbed down. Very good going really but not on that awe inspiring level such as what the Hidition Viento-R’s convey but more energetic than any 64 Audio offering or the Roxanne.

Soundstage is spacious in the most realistic of senses. It is not remarkably wide in a way so digital that is it is clearly put on. It is however very wide but the space is not always at use, it is only called upon for certain instruments or events during a track, making it all the more realistic. In the same respect it uses every other dimension as positively, especially height which is unlike anything I have stumbled across in IEM design, remarkable. The sound is also separated impeccably.

All in all I am very impressed with the sound, it is cohesive, versatile and shows a very high technical ability that lets it play with much more expensive flagships, it is a top tier no doubt. My biggest concern with the sound is my disappointment with some music, some music I can enjoy with the super revealing HD800s that sounds way too poorly recorded from these. These never are a madly musical earphone, they are not forgiving enough nor tuned that way. Instead they seem to do things properly and naturally in terms of timbre, it’s a different take, but still a great one.



When it comes to innovation in IEMs Lear are certainly at the forefront and while I was not won over by the NSS-U1, everything that is going on the BD4.2 seems fantastic. I like the new shell technique and the unique driver array creates what is probably the best hybrid IEM I have yet to hear. Add the crazy sound modification you can make quickly with the included tool and whats not to love?

Well, there is the concern that maybe they are fitting too much into an in ear monitor. These cast shadows over every other CIEM of mine, even the 12 driver Roxanne and A12. While I still get along with these in my ears and clearly adore the sound, Josh’s experience could not have been more different. I think the obvious conclusion was that even though his measured like mine, the sound was not getting into his ears properly because of the uncomfortable giant shells that ended in a thin and shallow nozzle. Worth noting is that there is also a universal version that I have not tried but have only seen very negative impressions of, leaving me thinking that with even the slightest of sub par fits the sound may not be optimal or even a little bit good! So while these perform easily good enough for me to recommend these to your consideration, do keep in mind your ear size if placing an order!


Turn the Page for Some More Measurements

Sonny Trigg