Disclaimer

I purchased the 64 Audio U8 IEM, as a part of the ‘Audio Enthusiast Program’, hosted by 64-Audio. As a participant I was offered a 15% discount. The discount has not played any role in the outcome of the review. It’s my honest, unbiased opinion.

Intro

I’m a audio enthousiast for a while. It all started with a Freecom MP3 player, I was one of the first in high school with such a ‘cool’ device. Later on I worked my way up via Creative Zen micro, Cowon D2, Hisoundaudio Rocoo P and the FiiO X3 (II).

My IEM’s followed along the way. In no particular order:

1. The Custom Art Ei.XX
2. Future Sonics Spectrum Series G10
3. Sennheiser IE 80
4. Logitech UE900
5. Philips SHE9800
6. Philips SHE9850
7. HiFiman RE0
8. T-Peos Altone 200
   

So through the years I heard some models from different brands and have experienced what they brought to the table.

 
The U8

So straight forward to the star of the show. The 64 Audio U8.



 
Why the U8?
My IEM list already gives a hint that I like my bass. The difficulty is that I don’t want it to overpower the other regions. If we look at the discription from the makers my choice was made:

“The 64 AUDIO U8 universal-fit earphones are premium, quad-low-driver "powerhouses". They are built on the revolutionary ADEL™ technology and feature eight miniature drivers per ear. Because of the ADEL™ technology and its effect on the human ear, they offer a listening experience that simply cannot be matched by conventional IEMs. Special attention was put on enhancing the bass in such a way that it does not "overpower" the rest of the frequencies. The result is an incredibly powerful, dynamic and hard-hitting bass that allows the mid-range and high frequencies to stay clear and vibrant.”

 

The technical features of the U8:

1. Transducer type: Eight precision balanced armature drivers
2. Transducer configuration: 4-low, 2-mid, 2-high
3. Quad Bore Design
4. Integrated 3-way passive crossover
5. ADEL technology
   

 
ADEL, what does it do?

ADEL stands for Ambrose Diaphonic Ear Lens. It acts as a second ear drum to relieve the pneumatic pressures that exists when closing off you ear-canal with a IEM.
The pneumatic pressure can trigger a reaction from your ear, it wants to protect itself, the acoustic reflex. When the reflex is triggered  youcan feel the need to turn up the volume, bad idea! To counteract the ADEL unit was born.

The most comprehensive explenation is found at the official website: https://www.64audio.com/adel and also this great video: https://youtu.be/bdiEnBppxhA

Packaging

The U8 arrived in a nice soft touch cardboard sleeve box. It held up well during the shipping in a bubble envelope. The U8 is packed in a very sturdy hard plastic case which protects it very well against the casual knocks and bumps.
The hardcase has space for:

1. Earphones
2. Cleaning tool
3. Shirt-clip
4. 2 pair of ADEL units
5. 2 pair of eartips
6. Small De-humidifier
   

All in all a very complete case with a good lay-out.
Available from the accessories shop is a small, branded, semi-ridged zipper pouch. Ordered mine from a 64 Audio dealer but I didn’t receive it yet.



 
Design / Built quality / Comfort

The IEM’s are made from a glossy solid black acrylic material. Edges are rounded so no sharp edges here. The faceplate is flat and has more defined edge, still not sharp. The logo’s on the faceplate are printed in clear white so they contrast nice with the solid black housing.
The quad-bore nozzle is the biggest of any of the other IEM’s I own. I have no issues with it but I can imagine that some will. You will need to have longer than average tips to cover-up the complete stem. 64 Audio gives you Comply T500 and some double flange sillicones which will do the trick. I’ve tested some other options, I’m coming back to the tips later on in my review.
The built-quality looks good to me, we’ll see how it holds-up in the long run. First impressions are solid though.
Comfort for me is pretty good. I can wear the IEM’s for hours without any itching. The feeling is even better with a 3rd party cable.

Sound / comparison

Now the most anticipated and subjective part of my review. How does it sound?

As mentioned before, I like a nice bass feel. So I was very curious how the U8 fared against my ‘dynamic bass love’.
Well, this is certainly my favorite IEM at the moment!
While it doesn’t have the kick and thump of for instance the Future Sonics G10 it presents me a balanced sound presentation with a good low-end, articulate mids and a nice high-end to give me a complete sound picture.
The lows extend very well and when the song delivers, the sub-bass is certainly audible and well presented. 64 Audio delivers what they stated on their website. The low-end is powerful when called for and the sub-bass surprised me. Fortunately the bass behaves and does not overpower the other regions. I’m really enjoying it.Mids are not pushed back. Vocals blend in very good and stay up front. High-end is clear and crips but a bit laid-back. Perfect for me as it has no sibilance and is non-fatigueing. Details overall is very good especially in the low and mid-range. Overall the U8 gives me a very natural sound that I like.

Kudo’s to Vitaly for the tuning of this beast.

Source: FiiO X3 II
Tracks used:

Guy Sebastian - Tonight again (538 Hitzone 74)

Robert Cray Band - Girl next door

Robert Cray Band - Won't be coming home

Avicii - Adicted to you (538 Hitzone Best of 2014)

Sheppard - Let me down easy (538 Hitzone 73)

Hardwell feat. Jonathan Mendelsohn - Echo (538 Dance Smash 2015 vol. 2)

Dire Straits - Brothers in arms (The very best of)

Diana Krall - California Dreamin (Wallflower)

Golden Earring - Going to the run (Veronica - Het beste uit de Rock Hits Top 500)

Joe Bonamassa - Jockey Full of Bourbon (An acoustic evening at the Vienna Opera House)

Joe Bonamassa - Sloe gin (An acoustic evening at the Vienna Opera House)

 
Comparison

1. The Custom Art Ei.XX

In comparison the Ei.XX is darker because it misses the mids a bit. The Ei.XX has 2 lows/2 tweeters and 2 super tweeters. This makes that the Ei.XX has a more extended high-end with the mids a bit recessed. The low-end is comparable with 64 Audio’s U8 taking the lead in sub-bass extension.

1. Sennheiser IE80
   The Sennheiser’s are a sort of reference IEM for me. Good bass and a complete package. The U8 gives the IE80 a run for the money and wins big time. The only thing the IE80 can bring to the table is bass slam. The dynamic driver has the upper hand here.
   

 
ADEL modules

With the available modules you can fine-tune the sound and feeling to your liking. I did some short testing and I’m sticking to the S1 module for now, primarily for the bigger, better bass.

1. S1
   1. Good bass response
   2. Nice viceral bass
   3. More intimate sound
2. B1
   1. Less isolation
   2. More neutral bass
   3. More depth
      

 
 

Tips

I’ve found the Comply tips to suit me best. The stock sillicone keeps itching after 15-30 minutes. Other’s recommended Spinfits but they are not working for me and because of the long nozzle the U8 sticks out even more.
For sillicone I settled with the Audio-Technica ER-CK50M tips. Fit’s over the nozzle and covers the full length. As Comply’s are a bit expensive I already bought some INAIR Air 1 from Amazon. Going to give them a whirl soon.

  

 
 
Cables

The Stock cable is good enough to start with and a most will never need to look to different cables. Personally I find the memory wire a bit too short and gets onto my nerves. Meanwhile I’ve tested some alternative cables:

1. Linum

Very comfortable, sound does not seem very different from the stock cable. I will probably end up buying another BaX for the U8 or wait a while and get a Super BaX.

1. Forza Audio Works Copper Series IEM Mk2
   1. Bigger bass
      1. Canceled by the ADEL B1 modules
   2. Toned down mids
   3. Slightly more air/spaceious
      

Certainly a difference comparing it with the stock cable. Is it better? Not sure. Depends on your preferences.

Conclusion

After using the U8’s for a couple weeks now I really like this IEM and can be happy with them for the time to come. The complete sound package it delivers is very enjoyable and makes listening to different genres a pleasant experience.
The ADEL tech certainly works. When I listen for hours and take the IEM’s out my ears do not feel any fatigue in contrary to other IEM’s. I don’t feel the need to turn up the volume any more. So while the U8, or it brothers/sisters, aren’t cheap they deliver what 64 Audio states. I can only aplaud 64 Audio and Mr. Ambrose for making this wonderful tech available and deliver it in such a complete package. Hopefully the technology will evolve and become even better in the future.
One thing is sure, I can’t wait to see what ‘the Bubble’ can do when paired with the universal line-up.