My impressions from listening to the Sennheiser HE-1

We arrived at Heimkinowelt Vienna at around 10:45 AM, where two Sennheiser experts were present to demonstrate the HE-1 to visitors and answer questions. Heimkinowelt itself provided us with prosecco and finger food for the occasion. Then I finally got the chance to take a look at this remarkable piece of equipment.

The list of superlatives and unique components that make up this masterpiece is long, so here is just a brief overview to highlight what makes the HE-1 so special:

 
• Marble from the very same quarry that supplied the marble for Michelangelo's David.
 
• Tubes specially manufactured for the HE-1, with all eight being closely matched to one another. If one fails, all eight are replaced. After 1,000 operating hours, an amber LED indicates that the tubes should be replaced even if none of them have completely failed.
 
• The DAC processes the signal in eight parallel paths and compares the results before forwarding the best possible signal to the analog section.
 
• The entire unit is actually "just" the DAC and preamplifier – the power amplifier itself is housed inside the headphones, and the silver ring acts as a heatsink.

Now let's get to what you're really here for: listening impressions.

Comfort

My first surprise was the comfort. I tend to react negatively to excessive clamping force, ear cups that are too small, headbands that are too stiff, and just about every common ergonomic mistake a headphone can make. I'd consider myself quite sensitive in that regard. The HE-1 was simply comfortable. The padding on both the headband and ear pads was extremely soft, pleasantly distributing the clamping force. Had I spent more time with it, I could definitely have worn it for much longer.

Bass

Electrostatic headphones have long carried the stigma of not being particularly capable in the bass department. Perhaps for that very reason, the HE-1 completely dispels this prejudice. With the very first test track, Supremacy by Muse, an absolutely massive bass response immediately made itself known, surprising me both in terms of quality and sheer quantity. After only a few minutes, it became clear that the HE-1 does not pursue a strictly analytical or neutral tuning. Instead, it deliberately aims for an impressive and emotionally engaging listening experience.

Midrange

Perhaps it is intended to make the bass feel even more powerful, or perhaps there are other reasons, but the midrange struck me as relatively recessed. Female vocals in particular sounded somewhat quieter in comparison to the low frequencies. At times, there was also a slight metallic coloration that reminded me of the tuning choices found in certain other well-known high-end headphones.

Treble

The treble was relatively restrained, presumably to make the HE-1 suitable for long listening sessions without causing fatigue. This was another surprise, as I would normally expect an electrostatic headphone to deliver airy highs and an endless abundance of detail.

Soundstage and other observations

The HE-1 does not create an enormous soundstage, but rather an exceptionally realistic one, with precisely defined depth and individual elements positioned perfectly in space with sharply defined edges. In my opinion, timing and spatial presentation are among the HE-1's greatest strengths, alongside its comfort.

The good news for all audiophiles who do not want to wait nine months—the current lead time—for a headphone system, let alone spend the amount of money required for the HE-1:

Today, it is entirely possible to assemble a highly capable system for significantly less money, for example based around the Susvara or Immanis. These headphones offer a more neutral tuning, and certain aspects can be adjusted, emphasized, or softened through the choice of source equipment, allowing you to tailor the experience to your own preferences.

If, however, you are looking for a modern, well-balanced high-end all-in-one system, the Warwick Acoustics Aperio GSE is also well worth a look.