Well, it offers a pretty balanced pallet. The bass has good body and impact. I would say it is on the full side of neutral. It is plenty big when the music called for it, but never takes over the sound when it shouldn’t. It doesn’t bleed into the mids. It offers fine detail retrieval and texture in the bass. It never turned into a blob of sound.
The mids follow suit well. I find the midrange takes on the most prominent role in the iDSD’s frequency range. They aren’t overpowering, or bloated in body, but there is definite warmth to the midrange that is quite pleasing. Although it played well with classical recordings, the slightly warm prominence of the midrange made vocal music my favorite selection with this here unit. As always, Jenny Lewis gets a lot of play, but Tegan and Sara, Garbage, Green Day, Derek and the Dominos all sounded great. While voices didn’t leap out of the headphones like they do on some systems, they were well positioned in the front of the music and never got lost in the din. Obviously, choice of headphones has a lot to do with this as well, but more on that later.
The treble is… gentle. It is there, and again, provides good detail, but it doesn’t have that sparkle that I often like. It obviously isn’t harsh, and it isn’t rolled off into oblivion, but those who like their treble to make a stand, probably aren’t going to be satisfied with the Micro iDSD.
This baby does offer up a pretty good sound stage though. Its width and depth are both quite good. I never felt the sound to be claustrophobic in the least. As for the 3D sound enhancement, I don’t care for it. What it sounds like to me is a boost the lower treble (that in itself is not a bad thing), but then it seems to take what should be right in front of you, and shuffles it off to the sides. It sounds to me more like odd stereo separating than a 3d enhancement, but again, just me. I know some other reviewers really like it, so your millage may vary, but it feels artificial to me.
Sometimes, when reviewing something, there is one word in-particular that seems to sum up the sound of something. With the Concero products I reviewed, that word is “electric”. The G109 would be “clarity”. With the Micro iDSD, that word is “polite”. This is why I am finding it hard to go into great detail about the sound. It isn’t doing anything wrong, but it is presenting the music in a very “polite” manner. I am currently listening to the Matrix M-stage HPA-3U (which is a warmer sounding unit than the iDSD), and the HD650, and this combo has more snap and drive than I got with the iDSD. Now, depending on the music and headphones, polite can actually work to your advantage.
Take for example the HE400s. I find this to be a fairly aggressive headphone, that isn’t afraid of getting into treble (see what I did there?). With my Concero HP, sometimes, it is amazing, other times… youch! Take the Radiohead song “No Surprises” for example. With the iDSD/HE400s combo, that song is an ethereal experience. On the Concero HP, it is harsh and a little unpleasant. The iDSD and the HE400s paired extremely well together. The same can also be said of the mixing the iDSD with the Grado SR80e. It keeps the harsher aspects of the SR80e in check while providing very good detail.
The biggest surprise to me is how well it paired with my RE400. The lower treble of the RE400 added a dash of spice to the proceedings, and the iDSD did a terrific job with filling out the sound stage. This is also the only time I used the XBass feature. I found the added bass to be very slight, but that very slight boost is just what the RE400 needed.
With the RE400, I use the iDSD in the eco/high sensitivity mode and it worked great. I tried it on ultra-sensitivity, and had to crank the volume almost up to the max, so this sucker should work with just about any IEM, no matter the sensitivity, and with an output impedance of less than 1ohm, there is no need to worry about psychotic impedance swings. It had no trouble making the HD650 blast on normal gain, and they claim (and I don’t have the phones to test this), that on turbo gain, it can drive the HE6. So, basically, they say, and I have no reason to doubt this, that the Micro iDSD can drive anything everything.
When using the iDSD as a DAC and outputting it to the Matrix, the results are a little dull. Sleepy is a good word for it. It might not be too bad feeding a Burson amp, which tend to be on the quick, forward side of things, but short of that… As for using it as a standalone amp, when fed from my Concero HP, it a pretty neutral sound, definitely more juiced with than with its built-in DAC. It wasn’t quite as spacious, but the energy is certainly up. However, if you are looking for a desktop amp, the Soloist SL and the G109s are only a little bit more, and are both better amps. As for using the iDSD as a portable amp, it sounds good, and it can, technically be used as one, but its size, and the placement of the 1/8 inch input makes that an awkward fit. Transportable, not portable after all. Plus, although you can separate the source and the amp, I have to say that this is intended as a total package. The sound of the DAC and amp complement each other well.
As far as the different filters go, I’m not one to mess around with them much. After dinking around with them a bit on some different music, I found the standard filter to give the vocals a little more pop, and then I stuck with that one for the rest of the test. As far as DSD goes, it worked. So, if that is your thing, knock yourself out. I’m still not convinced of the benefit to sound, and the file size gets obscene. To each his own, I guess.
In the end, it is hard not to recommend the Micro iDSD. It is well built, portable, with an amazing set of features and options, and excellent sound quality, so long as you are looking for a relaxed sound. You just can’t argue with its versatility.
Editor’s note: A friend of mine let me borrow his iDSD a couple of month’s ago already but I never got to writing about it. Like Dave said, the iDSd packs a whole lot of gimmicks together in one transportable unit. The iDSD to me was rather neutrally tuned and showed a lot of detail in reproducing the music. For my personal tastes it was a bit on the meh side and I found it more dry than musical sounding. That said, it did make the Sennheiser HD650 sound quite good and any amp that does that has potential. It just wasn’t my kind of sound. My friend is quite happy with his iDSD but I did notice he was interested already in trying different amps.