The Superdongles: Cayin RU7 and L&P W4

W4 sound impressions

I hear W4 to have a linear, neutral, and balanced tonality, without any one frequency dominating over another. That said, enabling DSP options like Tone will shift the balance slightly, making W4 slightly warmer and more euphonic with Tone 01, and more ‘analytically’ resolving and airy in Tone 02. 

Moreover, switching between filter options also has a small influence on the tonal shift, though to my ears and in repeated testing, these changes are subtle enough that IEM personalities will usually override any significant change in sound by switching filters or DSP settings. 

W4 has a very clean bass response, with excellent speed and texture and a slight sub-bass emphasis. That means midrange notes aren’t given any sort of warmth boost from the bass, and if there’s limited bass in the track, note weight can sometimes be on the thinner side (though not thin per se).

The same neutrality extends to the midrange, with vocals – both male and female – coming off as very natural, but also not particularly wet or organic. Clarity and transparency is the theme here, with gobs of detail and nuance from instruments and vocals alike. Some might find the timbre a touch artificial, but I hear it as close enough to natural not to raise any flags. 

Treble is likewise clear, crisp and very detailed, and remains neutral on the whole, with maybe a touch of boost in the air frequencies. Overall I find W4 to be classically neutral tuning, ideal for faithfully reproducing classical and jazz recordings, but with enough muscle under the hood to satisfy when listening to more energetic or bassy genres too.

Technical performance is W4’s greatest strength, in my opinion. This is a dongle that really blurs the line between typical small form factor technical performance (usually just ok) and the much higher-end performance levels of larger sources.

Staging is naturally wide and deep, not excessively so, but more than enough to avoid sounding cramped or intimate, even with cramped or intimate recordings. It helps that sounds seems to emanate from a pitch black background, and no matter how sensitive the IEM, you can be sure the background will always be ink black without a hint of signal noise.

As such, layering, separation and imaging performance is all top tier. Instrument placement is exceedingly precise on stage, and as long as the IEMs in use deliver the goods, W4 will ably support and enhance their attributes. 

Other technical aspects, like speed and dynamics, are also very good, though perhaps not class-leading. As such W4 can come off as slightly analytical at times, though I feel it still retains a strong sense of musicality with most of the music I listen to. I don’t find this to be a weakness, mind you, and if your preference favours a detail-oriented source, W4 is possibly the best current choice of all the dongles I’ve personally tested.      

Select pairings

FiR Audio Rn6. This is fast becoming the IEM of choice to calibrate my ‘reference’ sound. It has a beautifully balanced tonality, with a deep, rich bass, even-handed, full and clear midrange, and extended, slightly elevated treble that’s never harsh or spiky to my ears. 

With W4, Rn6 is the quintessentially transparent transducer. It makes full use of the technical strengths of the IEM to bring out subtle details, as well as I’ve heard them with any other source. Vocals are almost level with the bass, and treble is just slightly elevated, giving an added sense of clarity. Stage is very natural, not too wide or deep, just right. 

An excellent pairing, easily driven at about 50/100 in low gain.

FatFreq Maestro SE. Contrary to popular opinion, this breakthrough IEM by relative newcomer FatFreq is more than just a big, bold bass machine. Yes, it has one of the most eye-wateringly elevated sub-bass shelves of any IEM in existence, but the sheer quality of its drivers and the clever tuning further up the FR makes this a very balanced bassy IEM, and an outstanding all-rounder with my library.

With W4, I’m hearing more of MSE’s technical ability shine through. Smaller details are easier to pick out, and textures are better defined. I initially thought W4’s cleaner, leaner midrange wouldn’t work so well with MSE, but to my surprise, the added detail it renders compensates for any lack of warmth or note density. Female vocals are still on the wispier side, but they come off as very natural, and not recessed, at least when there’s no sub-bass pounding out my eyeballs. 

Despite how hard MSE is to drive, W4 keeps up nicely at around 70/100 in high gain. Since W4 has an exponential rather than linear volume curve, that’s still a moderate setting with plenty of headroom in the tank.

HiBy Zeta. HiBy isn’t really known for making IEMs, but Zeta could very well change that. With impeccable build quality and a smooth titanium skin, this has fast become one of my favourite easy-listening IEM: super comfortable, with big bouncy bass, natural vocals, and a silky treble that’s never too strident and dips in all the right places.

I feel Zeta doesn’t make the most of W4’s cleaner, leaner tonality for some reason, even though you’d think this would nicely complement Zeta’s warmer tonality. Vocals become a touch too wispy, and bass isn’t as rounded and bouncy as I know it can be. Treble is smooth, and the upper-mid peak isn’t strident, but the sound is also flatter and less dynamic. It’s still a smooth, easy listen, but for some reason W4 steals some of the warmth that I really like away from Zeta’s characteristic sound. 

As such, even though Zeta is easily driven at 60/100 in low gain, it’s not the best pairing to my ears. 

Sony IER-Z1R. Z1R is and remains my favourite IEM. But, it can also be quite source picky, and needs a decent amount of power to get it going.

With W4, Z1R is delightfully technical. Bass is tight and textured, and vocals are imaged beautifully dead centre and way off to the sides (when called for). While W4’s stage is generally natural, Z1R pushes it wider and deeper, with details everywhere and timbre accuracy to die for. Z1R also shows off W4’s deep black background, though some vocals can feel a touch dry on occasion with this pairing. This is a superb pairing, with W4’s technical chops nicely complementing Z1R’s outstanding overall performance. 

Continue to Cayin RU7…



Picture of Guy Lerner

Guy Lerner

An avid photographer and writer 'in real life', Guy's passion for music and technology created the perfect storm for his love of portable audio. When he's not playing with the latest and greatest head-fi gear, he prefers to spend time away from the hobby with his two (almost) grown kids and wife in the breathtaking city of Cape Town, and traveling around his native South Africa.


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