Preamble:
Pai Audio (http://www.paiaudio.com/indexEn.asp) is a relatively new audio company and based in Shenzhen, China. Established in 2014, they have specialised in manufacturing in-ears. According to their own information, the company that consists of 13 people has also got national elite audio developers in their team.
It is nice to see that Pai Audio who back on direct distribution through ebay and mainly AliExpress are continuously evolving and expanding their distributor and shop network that are now carrying their products as well.
My journey with Pai Audio started with their MR3 (which I reviewed here) that I bought without even knowing what it sounds like (at that time, there was not a single review) and was very positively surprised when it arrived, because despite its comparatively little price tag below $200, it could nicely compete with many Western models costing twice as much (by the way, it didn’t struggle at all outperforming my Shure SE425) and offered a really convincing spatial presentation and authenticity rarely found even in somewhat higher price ranges.
Now the time has come and Pai Audio has developed a new model for 2016, the MR4, which is equipped with four Balanced Armature drivers per side that are separated by a crossover with three acoustic ways. In contrast to the popular 2x lows, 1x mids, 1x highs configuration, the MR4 is using two drivers for the mids. Well, this is not that unusual as there are other quad-BA in-ears with the same layout, however where the MR4 differs is that it is using two drivers of a different model range for the mids. When I heard of that for the first time, I was pretty surprised and highly wondering if there could even be harmony and coherency in the midrange with two drivers of a different model range.
Well, how this rather unusual driver layout sounds and if I could get rid of my doubts will be covered in this review.
If you want to, you can also check out the Pai Audio thread: http://www.head-fi.org/t/781399/audio-pai-audio#post_11926956
Before I go on, I want to give out a hearty thanks to Alex from Pai Audio who contacted me and asked whether I was interested in doing an honest, unbiased review, and I surely was, so I received the in-ears free of charge which however does not affect my evaluation at all (which is true for each of my reviews, no matter if I bought the item or was given it for evaluation).
Important note: It turned out that I was unfortunately provided with a wrong information regarding the MSRP (I wish I received the info of the mistake on the spec sheet regarding the price earlier). So the real retail price is not $239 as wrongly marked on the spec sheet but instead somewhere around $300. Based on this information, the review was updated accordingly. Changes are marked in green.
Technical Specifications:
Price: ~ $
Drivers: 4; Balanced Armature
Acoustic Ways: 3
Frequency Response: 20 Hz – 18 kHz
Sensitivity: 118 dB/mW
Impedance: 45 Ohms
Max. Power: 125 dB SPL
Rated Power: 1.25 V RMS
Cable Length: 1.28 m
Delivery Content:
The MR4 that is available with multiple colour options arrives in the same well-known black Pai Audio cardboard box with magnetically closed lid that is covered by a black paper sleeve with the Pai Audio logos.
Inside, the accessories are the same and contain of a quick-start guide, three pairs of silicone tips and the in-ears themselves along with a carrying pouch (in addition, Pai Audio sent me an upgrade cable they are selling separately).
While the delivery content is quite okay like that, I would say that as the MR4 is already priced above $200, a zippered carrying case or small hard-case would have been more appropriate.
Looks, Feels, Build Quality:
The MR4 is ergonomically shaped and comes out of the same mould as the MR2, MR3 and DR1. My review unit arrived with the same translucent blue colour as I ordered my MR3 in.
The build quality is pretty good and the housings appear sturdy and are very precisely glued together.
Through the translucent shells, the MR4’s four drivers, internal wiring, the simple crossover network and the two separate sound bores of which each has a dedicated Knowles damper can be seen.
The in-ears and cables have got relatively tight and well-fitting MMCX connectors, so one can use third-party cables.
The stock cable, while not being the least springy, is pretty soft as well as flexible and not sticky at all. Instead of memory wire around the ears, it just uses tubes for keeping the cable in shape, so both the people who love and those who dislike memory wire are likely to enjoy it.
Unfortunately, the cable lacks a chin-slider.
Still, at the price point, they could have probably gone for a braided/twisted cable. I think a price increase of $15 while adding a carrying case and better cable would have been feasible.
The black upgrade cable I was also provided with is not to my liking at all and (in my very humble opinion) not worth to get: while it looks nice, it is quite stiff and lacks flexibility. So back into the package with it.
left picture: the quite good stock cable right picture: the rather stiff and springy upgrade cable
Comfort, Isolation:
The MR4 is ergonomically shaped, nonetheless it could be beneficial not to have the smallest ears.
In my large ears, fit is really good and I also immediately get a seal (in earlier Pai Audio reviews, I wrote that getting a seal was a little tricky for me, but since I have figured out what the best insertion angle is for me, inserting the in-ears is easy as the ABC).
The cables are guided around the ears with a memory-wire-free rubber tube. Microphonics are pretty low but could have been even lover if a chin-slider was used.
The MR4 is a closed-body BA in-ear, so isolation is high. It falls somewhere between the UE900 and SE425.
Sound:
My main devices for listening were the iBasso DX80, DX90 as well as LH Labs Geek Out IEM 100.
The largest included silicone tips were used for listening.
Tonality:
In short, I would describe the MR4 as having a relatively balanced and natural tonality with a quite smooth and easy-going character. It is just moderately on the warmer and bassier side of neutral (ER-4S and UERM as reference). So yeah, I would say the MR4 sounds basically like the Pai Audio MR3 from the lows to the midrange but lacks the MR3’s bright treble and is noticeably more even and smoother sounding up there.
Bass quantity is spot-on identical to the MR3 which has about 4.5 dB more bass than the ER-4S and ca. 1.5 – 2 dB more lower end impact than the UERM. So it has got a still fairly neutral lower end that is quite identical to the InEar StageDiver SD-2’s and Jays q-JAYS’ bass quantity, meaning there is enough impact that the in-ear does not sound too sterile for some but is still balanced and natural, neutral-ish enough sounding most of the time.
The lows’ emphasis starts at 500 Hz and reaches its climax around 180 Hz. From there on, it is kept upright down to 40 kHz and rolls somewhat off down to 20, which makes its lower end sound and measure exactly as the MR3’s.
The mids are then pretty much neutral and flat sounding, with just a very slight hint of warmth due to the lower and lower middle root.
Between 1.5 and 5 kHz, level is evenly somewhat in the background, giving a fatigue-free yet not too relaxed or dark character. Above 5 kHz, level comes back with a broad-banded ear resonance around 6 kHz in my ears that is however not narrow at all and doesn’t go past the ground-line. Around 8 to 9 kHz is where I can spot a broad-banded and yet so slight emphasis that is no more than 1.5 dB above 0 in my ears.
In the super treble past 10 kHz, level starts rolling off after 12 kHz. There could be a little more subtle sparkle above 10 kHz, but I am not really missing anything at all and at least the Pai’s treble extension is somewhat better than the Shure SE425’s.
Overall, I am quite positively impressed by the harmony, coherency and that there are no steep peaks or narrow dips all over the whole frequency range.
On another note, the MR4 is never wrong and conveys with a very natural and realistic timbre. I think Pai Audio has done a really nice tuning job with the MR4 and has basically created an MR3 with a more even and smoother upper end and yet so slightly warmer mids.
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Approximated frequency response (using the Vibro Veritas coupler with an applied "pseudo-calibration" and the diffuse field target - just to get a general, approximated idea of the sound and not for lab-grade precision (usually, my Veritas "calibration" shows too little level around 3 and 6 khZ and sometimes somewhat too much around 9, just to get an idea where it is not that accurate)):
As said above, one should (mentally) add around 10 dB around 3 kHz as well as around 5 dB around 6 kHz to get closer to a real GRAS in-ear measurement coupler's response.
More frequency response measurements can be found here: http://frequency-response.blogspot.de/p/i-all-measurements-i.html
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Resolution:
I would say the MR4 is pretty well-resolving and could be considered as
Its bass is pretty quick and really well-controlled, which is however not surprise as it is using a non-vented BA woofer. Yep, the bass’s control, speed and lower-end details are identical to other BA in-ears in the price range around $400 that have got a closed-back BA woofer.
The treble sounds adequately detailed and especially very even and natural. Because of this evenness, it might be a little difficult to objectively compare the MR4’s upper end to other in-ears that have got steeper peaks and less evenness in the treble. Though, I would say that many other BA in-ears around and below $400 are somewhat better differentiated and more refined in the treble, including the cheaper MR3 (but again, this is a little difficult to objectively judge because of the treble’s evenness, and for ~ $239, the MR4 really does nothing wrong at all in the upper range).
Moving on to the mids: While these are tonally really good, they appear a little bit veiled (which I bet is because of the different drivers being used for the 2-driver midrange way): It is not any bad at all and does not appear blunt yet and also outperforms quite a number of dynamic in-ears in this price range when it comes down to speech intelligibility, but somewhat lacks behind the bass and treble details. I think a conventional 2x bass, 1x mids and 1x highs crossover layout or using a 1x bass, 2x mids and 1x highs layout but with the same drivers for the midrange would have been more beneficial for the sound. If I hadn’t known that the midrange uses two different drivers, I would have just said that it just appears slightly less detailed compared to the upper and lower frequencies (speech intelligibility and details are good in the mids, but everything in the mids appears like being behind a very thin and translucent curtain), but at least now I know why I get this impression.
On a different note, I have expected the midrange to sound quite skewed and strange, maybe hollow because of the use of different drivers for the same acoustic way, but in reality it has turned out so much better than expected, with just a quite slight veil. Nonetheless, the MR3 (and also UE900 whom I find to be somewhat veiled in the mids, too) has got the somewhat better resolution in the mids but is less even and natural in the treble.
Overall, I would say the resolution is
Soundstage:
What I am happy to hear is that the MR4 has adopted a key feature of Pai Audio’s other multi-BA in-ears: its soundstage is pretty good and not only features a nice width but also a decent depth and sounds well-placed and separated, but especially features a really nice authenticity that unfortunately many BA in-ears around $400 are lacking and is usually found at much higher price points (some exceptions are the InEar StageDiver SD-2 and Audio Technica ATH-IM03, two in-ears that also have got a really nice and authentic soundstage).
In contrast to the MR3, the MR4’s soundstage has got more width and a little less depth but has still got some really nice layering capabilities. Instrument placement and separation as well as 3D-ness are really good and generate the impression of a very authentic spatial presentation. The soundstage’s airiness and the generated air/empty space around instruments are really good as well.
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In Comparison with other Balanced Armature In-Ears:
Let’s see how the MR4 stands up against some more expensive multi-BA in-ears.
Pai Audio MR3 (now $199):
Both have the same bodies and cables.
The MR3 is more on the more v-shaped and brighter side of neutral whereas the MR4 is rather on the somewhat bassier and smoother side of neutral and could be considered as balanced, natural and smooth.
Both have got similar bass quantity and extension but the MR3 appears slightly less bassy as its treble is more forward.
In the mids, the MR4 sounds just very minimally warm whereas the MR3 is spot-on neutral here to my ears but a slight bit more distant.
The MR3 is brighter in the treble and extends somewhat better above 10 kHz but the MR4 is more even and therefore smoother and more coherent in the treble.
Both have similar bass quality and control whereas the MR3’s mids are a bit more detailed. When it comes to the treble, the MR3 appears a little more differentiated and separated as well, but as written above, this is a little difficult to objectively judge because of how even and coherent the MR4 is up there.
The MR4 has got the somewhat wider soundstage while the MR3’s is a little deeper. Both are however identically precise and especially authentic.
Overall, I would say the MR4 is overall a side-grade to the MR3 with somewhat less detailed mids but the more even and realistic upper end and the same spatial authenticity. Based on the price difference, I would personally rather pick the MR3 though despite its less even treble, as it is overall somewhat more detailed in the mids and treble and has got the even better price-performance-ratio.
Logitech UE900 (MSRP $399, bought for ~ €349):
The UE has got the smaller shells but both in-ears fit identically well in my ears. The UE has got the superior cables.
Both head into a more or less comparative tonal direction.
Both have got about similar bass quantity but the UE has got more sub-bass impact. In the mids, the UE appears a little skewed and tilted to the slightly darker side whereas the MR4 seems more realistic and not skewed. In the middle treble around 5 kHz, the UE is a bit more relaxed but has got the narrower, more sparkling upper treble peak (so the MR4 is more even in the upper end).
In terms of bass, the MR4 has got the slightly quicker attack while both are equally controlled. In the mids, while the MR4 is tonally more correct appearing, the UE900 is slightly more detailed although its midrange’s details also slightly lack behind its bass and treble. In the treble, the UE appears a bit better differentiated and layered but as mentioned above, it is a little difficult to objectively judge because the MR4 is more even. Though, I would say that the UE is overall somewhat better resolving while the differences aren’t that large, nonetheless the MR4 has got the more authentic (yet slightly less detailed) mids.
When it comes to soundstage however, the MR4’s is wider, has got more depth and is also better layered and has got the superior separation while the UE’s appears a bit more compact and lacks depth in comparison and does not sound as precise or authentic.
Fischer Amps FA-3E (bought for €329):
The MR4 has got the somewhat larger bodies while the FA-3E’s are smaller. Nonetheless, the Pai is a little bit more comfortable in my ears. The Fischer Amp’s cable is more flexible.
Both in-ears head into a comparable tonal direction but the FA-3E is a little bit more on the neutral side with a slight bit less bass quantity but also a dip in the middle treble that makes vocals’ overtones appear a little relaxed.
The MR4 has got minimally more bass (less than 1 dB though), but both appear about comparable in terms of quantity because the Pai’s lower end is a little quicker. In the sub-bass, the FA-3E is a bit more present whereas the MR4 is a little warmer in the root.
In the mids, the Fischer Amps is a little brighter than the slightly warm MR4.
In the treble, the MR4 is somewhat more even and also smoother. Only at 5 kHz, the FA-3E is somewhat more relaxed.
The MR4’s bass is a little quicker while in-ears are comparatively controlled.
In the mids, the Fischer Amps appears a wee bit more detailed by just a smidgen, but in the treble, the Pai Audio is somewhat more refined and detailed.
While the FA-3E has got a pretty nice and well-rounded soundstage from what I perceive, the MR4’s is somewhat wider and also a little deeper. The Pai Audio’s stage is also better layered and more differentiated with the higher authenticity and audibly better portrayal of emptiness around instruments.
The FA-3E was my favourite quite balanced sounding in-ear in the price range below €350 for outdoor use – and I think the MR4 has displaced it, sounding tighter and somewhat better resolving as well as having the more authentic and precise soundstage
Westone W4R (bought for €439):
The Westone is easier to insert but both are equally comfortable. The W4R’s cable is superior.
The Westone heads into a somewhat different tonal direction, sounding rather full and more relaxed.
The Westone has got the somewhat thicker and more resolute midbass and upper bass and is the overall thicker sounding in-ear with somewhat more root quantity, though it rolls somewhat more off towards the deep sub-bass.
In the mids, both are about comparatively warm but the Westone’s mids appear a bit more relaxed due to the 5 kHz dip.
In the treble, the MR4 is more even and has got the less narrow and smoother upper treble.
Regarding resolution, the Westone is on an audibly higher level. Its bass appears slightly quicker while both are equally controlled. In the mids and treble, the Westone is the more detailed in-ear as well, revealing more minute details with authority.
The Westone has got a really wide soundstage that however lacks spatial depth in my ears. The MR4’s is just slightly “narrower” but has got audibly more spatial depth. While the W4R separates instruments slightly sharper, the Pai Audio is able to generate more air around instruments and has got the higher authenticity.
So while the Westone is the audibly higher resolving, more detailed in-ear, the MR4 had got the better soundstage and sounds more authentic (a key feature that all of Pai Audio’s multi-BA in-ears I have heard so far have in common).
Conclusion:
The MR4 offers a very enjoyable, natural and extremely even and coherent, realistic sound with a really good soundstage and high authenticity.
The value for the money is
Though, I would wish a better carrying case at the price point, along with a better cable and the midrange could also be a little better resolving compared to the bass and treble.
The MR4 has some really strong attributes with its superb imaging as well as authenticity and high evenness. What it could have though is a somewhat more resolving treble and especially midrange. While detail retrieval is adequate for the price, the competition at the price point is becoming more serious and delivers a somewhat higher midrange and treble resolution (, yet about most of them don't reach the same great imaging and authenticity capabilities).
The MR4 is for those who love a balanced, smooth and even sound signature and have a high preference for really good imaging and high authenticity.
What I wish for though at this price point is a more premium, braided/twisted cable, a sturdy carrying case and probably a somewhat more detailed midrange.
Overall (based on the corrected price information), I come to a final conclusion of good 76% or 3.8 out of 5 stars.
