The HarmonicDyne Helios is the first open-back headphone I bought which actually changed the way I experience headphones. It is priced at 180$, but I bought it through the Indiegogo campaign for 130$ which is an awesome value. Fun fact, I was actually the first person to purchase this headphone - my order number there was literally #1. Anyway, I will do my best to describe my experience with my Helios comparing it with my Sennheiser HD 560s in the same price point, which I recently bought for mixing purposes, and which I will use as a standard for almost perfect sound technicalities.
- The Helios is a very natural and airy sounding open-back dynamic headphone with a very nicely implemented V shape - rolled off sub bass, slightly more bass, slightly more treble than my flat HD 560s. Of the two pairs, this makes the Helios more punchy, fun and enjoying to listen to for almost all genres.
- Detail retrieval is great and competes very well with HD 560s - very, very close if not the same.
- Instrument separation and dynamics of the Helios are very good and very similar to the HD 560s.
- The bass and sub bass is very clean, never distorted or bloated, and it doesn't seem to make the lower mids muddy at all.
- The mids are not recessed at all - they are clean, present and blend very well with the lows and lower treble and are very pleasant for vocals, acoustic and electronic music.
- The treble of the Helios is the part that I did not like as much as I do on my HD 560s. The Helios' only weakness is the elevated sharp and more energetic treble, which is only true for my treble sensitive ears. For other folks it may not be an issue at all, which pretty much makes the Helios almost flawless. This weakness also brings slight sibilance to the vocals and some instruments, which is not terrible, but noticeable. This weakness is also the reason I don't find them particularly great for orchestral music and some other genres that may require a more balanced sound signature.
Sound stage and imaging:
- Helios' sound stage is similar to the HD 560s - big, wide and relaxing!
- Imaging on Helios is very good, but it's a bit more precise on the 560s.
- "Dance Of The Hours" by London Symphony Orchestra has noticeable lack of sub bass which makes some low percussions miss that nice and full rumbling body filling the stage, but it's not bad at all.
- "Brothers In Arms" by Club For Five sounds very good and soothing, male vocals are a bit more heavy, but not too much - it's in a very good spot for male vocals.
- "Herdsman" by Zhao Cong and Hans Nielsen - the percussion swarm in the middle sounded clean and similarly separated and "countable" compared to the HD 560s.
- "Why So Serious?" by Hans Zimmer - during the heavy sub bass rumbling in the middle of the song, I noticed ever so slightly less control and precision on the Helios compared to the HD 560s, but it is well controlled and textured nevertheless.
- In "Letter" by Yosi Horikawa I can hear the pen coming from a more precise and well defined spot with the HD 560s, but it is of course by a small margin compared to the Helios.
Build & accessories:
- I think all of us can agree that the metal pattern on the cups looks so beautiful! I am not a big fan of the headband that wiggles a bit where it adjusts and is a bit less comfortable to me (which can be easily fixed with Dekoni nuggets though), but at least so far they feel very sturdy.
- Luckily, the cable is a common dual 3.5mm, with good length and doesn't tangle - actually very good! The stock pads feel very smooth with that suede material. They are very big, soft and exceptionally comfortable even if you use glasses!
- Stock suede pads.
- FiiO BTR5 portable DAC/Amplifier, connected with LDAC Bluetooth codec
The HarmonicDyne Helios performs very close if not similarly to the HD 560s in terms of imaging, soundstage and detail technicalities. What makes the Helios stand out is the punchier bass with sub bass roll off and the more energetic treble all forming a great sounding V shape. The Helios is not exceptional, but absolutely great and competitive for the price of 180$, which competes with my studio-grade HD 560s very competently. I absolutely recommend these headphones for all music genres and to everyone who doesn't have very treble sensitive ears.