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REVIEW: Head-Direct RE2 IEM and Fiio E5 amp

post #1 of 89
Thread Starter 
I've had many people ask me about the best IEM value in the $50 category after I posted my review of the Nuforce NE-7M, especially by those asking about the Head-Direct RE2. So I set out to acquire a pair of RE2 to review and become more informed about other options in this price range. In that price range I already have the $49 Nuforce NE-7M that I bought to use with my iPhone 3G, and I have a depodded IM716 that I bought from buy.com on black friday 2007 for $49, plus an NE-8 that my son uses ($69) and a pair of JVC Marshmallows and Aircushions that fall in the $10-30 range. I've also previously owned an ER-6i about a year ago that cost me about $70 back then. The RE2 fit right in the middle of these in price, at $49 and are currently on sale with a free Fiio E3 booster included. I believe these were offered at a special price of $80 when introduced, with an MSRP of $99 after that. I do not know how long they will be on sale.

EDIT - they will remain on sale, and now are a steal at only $39 (without being stuck with the E3 booster), but I would recommend buying the Fiio E5 at the same time and you will get a lot of enjoyment from the combo. Obviously having the RE2 as their own "in house brand" has it's advantages when it comes to pricing. Head-Direct.com | RE2

The specifications of the Head-Direct RE2 are:

Driver unit: 9mm
Impedence 32OHM
Sensitivity 103dB/1mW
Rate input 10mw
Max. input 30mw
Feequency response: 20Hz ~ 18KHZ

I gave the RE2 220 hours of burn-in, but that was overkill since I simply keep them running until I had time to do my review. Probably about 100-150 was all that was needed. They seemed to have less bass when new than they do now, and the mids and highs were a little grainy out of the box. Using my Macbook and iBasso D10 DAC/amp I was able to confirm their claimed frequency response of 20Hz to 16Khz, but my 46 year old ears don't go higher than that. However, at 20Hz the test tones are at least 3-4 dB down from the volume produced at 25Hz, while at 25Hz it seems to be only 1-2 dB below the volume 31-40Hz tones. So, they are reasonably flat to 25Hz and still make some useable noise at 20Hz. That is about as good as my RS-1 and HD600 can do in the bass extension, so I shouldn't be disappointed other than the NE-7M are flat to 20Hz and audible at 16Hz to my ears (like my $850 ES3X).

Most of my listening for the review was done with my iPod 4G Nano, with and without the Fiio E5 and using a compact stevenkelby Piccolino wire LOD. I was able to use the included medium silicone tips, the small black bi-flange tips and the larger clear bi-flange tips. The large clear bi-flange and medium black single flange tips provided the most comfort, while the slightly itchy small black bi-flange sounded the best. The clear large bi-flange tips seems to slightly enhance parts of the upper mids and highs and the small black bi-flange sounded slightly better, but those clear tips are more comfortable so I stuck with them. I also tried the Complys T400 foam tips which fit and sounded fine, but I could not get them deep enough into my ears for a complete seal every time without a bit of forcing them in deeper.

I found the RE2 to be a detail oriented headphone with a hint of brightness. And while having a deep bass extension it's bass was not as prominent as the somewhat forward mids. Despite the forward mids imaging is good, and so the RE2 were still suitable for classical music like Arvo Part: Tabula Rasa, and Handel Messiah, Beethoven's 7th, Dvorak Symphony #9 or Prokofiev Violin Concerto 1.

I enjoyed the RE2 with Jazz and Acoustic Folk and Electronic the most. The detail and speed was good enough to portray acoustic guitars, string bass, cellos and other strings well. I did think the upper mids were a bit prominent for piano and saxophone, and did not enjoy some of my music with those as much. Male and female vocals like Jack Johnson, Dave Matthews, Diana Krall, Nora Jones, Rachel Yamagata and Shelby Lynn were clear without intrusion into the lower mids by the bass like some earphones. However, in this case I still would have preferred a bit more warmth with vocals and saxophone (this is where the Fiio E5 comes in later).

With electronic music like Infected Mushroom and Kenji Williams the bass was tight and controlled, punchy and quick, unlike my Denon C700 which would sound somewhat sloppy and bloated. With electronic I felt the bass was not lacking, despite being less than the NE-7M or C700. However, in some rock music like Metro Station, Coldplay or Katy Perry I did wish for more bass impact and less mids. Un-amped the RE2 did a better job than my IM716 which crave power, while amped the IM716 at 33 ohm pulled slightly ahead with more transparency and less coloration. With all the IEM listed being amped, I also preferred the RE2 over either of the JVC and slightly more than the NE-8, but I liked them slightly less than the NE-7M. However, the RE2 amped by the Fiio E5 were still a match for the un-amped NE-7M. With the NE-8 amped the NE-8 sounded better than when not, but they seemed to have some artificial reverb or acoustics (or cupped hands sound) added to the mids when compared with the RE2 which are a little cleaner sounding. Also, you must remember that the NE-7M do have a mic and button controls for the iPhone and some iPods, which means losing those features if they are used amped.

As mentioned, I also took this opportunity to try out the Fiio E5 ($22) amplifier, which I have been reading is an upgrade to the Fiio E3 that I already owned. I get MANY inquiries about the E5 vs iBasso T4, and have not been able to answer them till now. I also gave the E5 almost 200 hours of burn-in while burning in the RE2, which seemed to help it open up and sound fuller. When I first got the E5 I could barely tell the difference in sound with bass boost on or off, which changed with burn-in. I've noted previously that the E3 is a noticeable upgrade in sound to my previous Boostaroo 3-jack booster, although it still takes out a little bit of the details and spaciousness from the music vs listening directly from the headphone out. The E5 does not have that problem. The E5 offers the added features of a volume control, so it can be connected to an improved sounding line out dock, and it also offers USB charging, a bass boost switch, and a nice shirt clip. The form factor and clip design is very similar to that of the 2nd Gen iPod Shuffle.

The posted specs of the Fiio E5 are:

Output Power: 150 mW (16 ohms Loaded); 12 mW (300 ohms Loaded)
Signal to Noise Ratio: More than 95 dB (A Weight)
Distortion: Less than 0.009% (10 mW)
Frequency Response: 10 Hz - 100 kHz
Suitable Headphone Impedance: 16 ohms - 300 ohms
Weight: 30g
Power Supply:build-in 200mAh rechargerable battery
Dimensions: 44.2mm x 38 mm x 12.6 mm
Preamp Opamp: OPA2338UA
Poweramp Chip: TPA6130A
15cm 3.5mm to 3.5mm audio line
80cm 3.5mm to 3.5mm audio line
60cm USB-A

So, as I indicated before, the E5 sound is a noticeable upgrade to the Fiio E3, and with the RE2 (and others) there is no hiss. Imagine my SURPRISE when I plugged my 124dB/mw Westone ES3X and still heard NO HISS, at least not until the volume was turned up to such high levels that would kill my ears if the music had not been paused. It actually sounded good with my ES3X too, while the E3 has enough hiss to render it unusable with the ES3X. And unlike the E3, the E5 detail and soundstage (via LOD) is not less than that of the 4G nano headphone out. What it does do is warm up the sound of the 4G Nano a bit, and even with the bass boost off the RE2/E5 seems to have just a little more bass than via the headphone out as well. With the bass boost switch activated the RE2 sounded even better - although I could still enjoy them right out of the headphone jack, I preferred them much more with the E5 (with or without bass boost), and especially with the E5 bass boost on.

I then ran the 4G Nano with the RE2 connected to the Fiio E5 via LOD and also plugged in my Nuforce NE-7M into the Nano headphone out, so I could do quick switching between the two IEM with the same music and the volumes matched. With Rachel Yamagata "Elephants" the RE2 sounded very similar to the NE-7M with the help of the Fiio E5's natural warmth. Despite the slightly more forward mids of the RE2, I could put the NE-7M in one ear and the RE2 in the other and it did not sound wrong to me. Going back and forth between the unamped NE-7M and the RE2/E5 playing at the same time revealed them to be roughly equivalent, with a slight edge to the RE2 in terms of detail, and a slight lead to the NE-7M in terms of refinement or smoothness.

Switching on the bass boost on the E5 bumped the RE2 bass about another 3-4 dB without wrecking the lower mids on vocals, and put the bass a couple of dB above the NE-7M unamped (and about 3-4 dB above the RE2 unamped via headphone out). This was my preferred combination to enjoy the RE2 to their fullest.

I also tried comparing the $99 iBasso T4 via LOD vs the E5 and found the T4 to increase the size of the soundstage and the air or space just a bit over the E5, and the extra detail typically available via the LOD became more apparent. I confirmed this by switching from the RE2 and NE-7M to listen to my modded re-cabled D2000 and HD600. There is almost no HISS with the Westone ES3X, but it's not completely silent when the music is paused if listening carefully (95% silent and much less hiss than macbook headphone out or 5.5G ipod video). I do feel the T4 is a warm amp like the E5, but it's bass boost is more subtle than the E5 boost (seems like a 2-3 dB boost). While the $99 iBasso T4 is a better amp in detail and air and ambience, the $22 E5 holds up better against the T4 than I expected it to. The E5 is a good value that takes little away from the sound of the line out dock - and while matching the SQ of the Nano headphone out it adds a bit of power and warmth to the sound where needed.

Both amps still suffered a bit in trying to output enough current to drive the low impedance D2000, yet they both are an improvement over the power of the headphone out. Both amps handled driving the 300 ohm HD600 better than they did with the current-eating D2000. On Rachel Yamagata "Elephants Instrumental" they also both drove the HD600 to sounding like it was a binaural recording. They could also get very acceptable volumes out of the HD600, which I did not expect from their size. Although neither is my preferred portable amp with HD600 they do get the job done in a pinch, at the expense of not sounding as lively and energetic as more costly amps. Even the iPhone 3G headphone out sounded clearer and more transparent with the HD600 than the 4G Nano, although not coming close to the volume of them when amped via the 4G Nano.

Before anyone asks, I did not include my more expensive Phonak Audeo, Westone 3 or Sennheiser IE8 in this comparison, as they are on a different level from these IEM. Although my reports of the Sennheiser IE8 have not been entirely favorable, they are improving with 225 hours of burn-in and they sound better than these, but just not as good as the Phonak amped or the Westone 3 amped or not.
post #2 of 89
Great review as always, Larry.
post #3 of 89
Thread Starter 
Originally Posted by ClieOS View Post
Great review as always, Larry.
Thanks. I almost forgot you did a review of these once, didn't you (in a big multi-IEM review)? Does this match your findings?
post #4 of 89
Originally Posted by HeadphoneAddict View Post
Thanks. I almost forgot you did a review of these once, didn't you (in a big multi-IEM review)? Does this match your findings?
About the same, on both the IEM and the amp actually
post #5 of 89
No pictures?
post #6 of 89
Very nice review.
Funny enough, I got the RE2, NE-7M and the Fiio E5! :P
Even stranger is that you didn't comment at all about how the NE-7M cannot be used with the Fiio E5 since the NE-7M has too low of an impedance = hiss.
That said, ignoring the hiss, the NE-7M detail really opens up with the E5.

Little bro has the RE2 + Fiio E5 combo while I have the NE-7M's
post #7 of 89
awesome review, I went with the re2 and fiio e5 combo over the ne-7m I was considering, from your findings, this looks like a wise choice.
post #8 of 89
are the RE-2s better than PK3?
post #9 of 89
Great review, E5 still seems to stand tall. Might need a grab one for my PK1s.
post #10 of 89
Thread Starter 
Originally Posted by ka-boom View Post
No pictures?
Not at 2AM no. I'll try to get some up by tomorrow.
post #11 of 89
Nice review, thanks!
post #12 of 89
So with the Fiio E5 there's not much if any hiss in the RE2 and others. Is the NE-7m one of those others? I know they had issues with the E3 and it seems that e5 has fixed some of those issue for other headphones. The reason I'm asking is that I have a Fiio E5 and am I in the market for another set of headphones. Upon reading your NE-7m review and doing a little more research, I'm currently leaning towards those. Most of my music is electronic in nature with a large appreciation for female vocals and bass. Which would be a better fit with the E5, the NE-7's, RE2's, NE-8's? If the NE-7ms is still rubbish with the E5 ( in terms of hissing), would you still take those un-amped over the others?

post #13 of 89
Thread Starter 
In my review I found my particular E5 does not have hiss with even my most sensitive IEM, the 124dB/mw Westone ES3X. The NE-7M did not come close to hissing with the E5. I don't know if all specimens are as silent as mine or not.

As for what to pick, you'll have to make that decision yourself. I gave plenty of clues about how the IEM sound vs each other, you have to decide what features are best for you.
post #14 of 89
Thread Starter 
Updated the review above with a link to the RE2 sale price which is now $39 (without the E3 booster), which saves you money that you can put toward the improved E5 instead. Nice.
post #15 of 89
hmm even though i just bought the pk3, im really tempted to buy the re-2 now that it's $39.. would it be dumb to have both? i kinda wanna see what IEM's are about .. but i was thinking of getting the PFE's in the future... should i get these instead?
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