Pros: Single-handedly matches top-shelf performance
Cons: Non-spiffy looks, subpar build quality and comfort
I am already on my way out of the Head-Fi community for personal reasons, but I will add my final contribution with a review of the Superlux HD 681 headphones, knowing full well that I already have gone through and tried over 50 headphones under the $500 mark, I must at least have one thing worth saying. I feel that the Superlux HD681 is that thing, being something that none of the other headphones I have come across can do quite well in terms of dynamics and neutrality. But, before I dive into its own characteristics, I will give some perspective of my headphone history and then I will explain my thoughts on the Superlux headphones to conclude.
Years ago, I started out with the lowly Sennheiser HD201, plasticky in both construction and sound, and I knew then that there had to be something better than that current audio experience. Soon, I was succumbed by a rich yet detailed Sennheiser HD555 and it gave me an experience that few speakers had been able to offer me in the lower midrange and bass regions, but it seemed somewhat subdued--yet still detailed--in the upper midrange and treble regions. A year later, I found myself owning a Grado SR225i, having a more forward midrange but, interestingly enough, because of my extremely small ears causing the foam to surround them like a circumaural headphone and the plastic screen to press against my ears, its treble was less detailed, quite slower and much darker than my HD555, much to my dissatisfaction. Quickly, I sold them on Amazon marketplace and I nearly regained the money invested in their purchase, then going on to try each of these headphones as well as many others for at least two hours either demoing or owning them over the years: Audio Technica ATH-m50s, Grado RS-2i, Superlux HD668b, Shure SRH840, AKG Q701, Sennheiser HD558, Sennheiser HD598, Sennheiser HD650, Beyerdynamic DT770, Beyerdynamic DT990, Beyerdynamic DT880. Of all of these models, I came to feel most sonically comfortable with the Beyerdynamic DT990, which, while having a clearly colored presentation, still had all of the other audiophile necessities like dynamics and extension in the spades. However, I still had my reservations about the upper midrange being a bit overshadowed by the bass and treble as well as the slightly overexuberant treble, but I recently sold them to an eBayer and parted with them to continue on other paths in life.
Now, I needed something very inexpensive to take its place and so I began my search online for a likely candidate and the Superlux HD681 soon came into my radar. I had already owned the Superlux HD668B and raved about it for a time, only later to find myself considering it to be a bit lifeless like the Grado in my rare "small-ear circumaural scenario." However, it seemed to have more positive comments than the HD668B, not to mention having graphs that looked equally impressive, so I went on to order them. Within a few days, a box was on my doorstep and I was quick to bring it indoors and open it.
Once plugged in, the Superlux HD681 gave me a very pleasant surprise. It was neutral, vocals and instruments not having any warm or cold or energetic or lush quality to them like any past headphone gave, but an almost eerie realism to them, just like a live concert. It was dynamic, meaning that every part of the sound spectrum seemed to move in harmony and shift with a unison quickness as it would in real life, and it did not have the no-nos of an overindulgent upper bass stealing the dynamics from one area like the HD668B had to try to make its point. It had soundstage, just as the recording had it and not a pleasingly named technology that would be only partially beneficial at best, an accurate portrayal of changes of volume, tone and placement that made anything incredibly easy to spot in a recording. This was the same I found with anything I threw at it, from the wild and rhythmic classic Bohemian Rhapsody by Queen to the symphonically splendid Hawaii by Elmer Bernstein and too many other tracks to name. And, to my surprise, no razor blades cut into my eardrums in the process like Tyll Hertsens of Innerfidelity has suggested, which, in my experience, a Beyerdynamic DT990 could do much more easily if it did have such a sound, but it certainly does not have.
There is no doubt about it. I got rid of my audiophile equipment and was handsomely rewarded in return by something even better for much less than I could ever dream of. I hope that this news may be of help to you because I find the Superlux HD681 to do everything right on all fronts. I pull up a song that I typically use for demoing, test for a certain aspect, such as an instrument for its neutrality, or ambiance in a concert venue, and it passes with flying colors every time. Give it a try. You have nothing to lose except $30.