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Ollo Audio headphones

I bought a new pair of exceptional open-back headphones by Ollo Audio, the S4X model. Here’s a quick review.

Simone Silvestroni's avatar
Ollo S4X headphones
Ollo S4X headphones

Four days ago another producer brought to my attention a fantastic 24-hours-only 40% discount on the S4X reference headphones by Ollo Audio. I bought them. Several months ago, after reading a tempting professional review of the same model, I opted out because I had different priorities and deemed them unaffordable.

Generally considered as the NS-10 of headphones, for several years the trusted classic Sony MDR-7506 were my go-to. Never had particular issues, except for ear fatigue over long sessions.

5 things I love about Ollo’s S4X

  1. Attention to detail. Everything is hand-crafted with extreme care and competence, starting from the chosen materials. The first thing that surprised me was the self-adjusting strap present in the headband. Made of articial leather, it smoothly adapts to any size.
  2. They’re open back with a flat frequency response. As a professional in the music industry with a permanent tinnitus, the peace of mind of having an open back pair of cans is critical. They allow air to pass through ear cups from the rear of the speaker, eliminating the problem of resonance and low-frequency build-up caused by the enclosure.
  3. The sound is magnificent, moving the bar of perceived audio quality up several notches. After loading a mixing session I’ve been working on yesterday, I could quickly pinpoint a few spots where to fix a less than perfect amount of low-end in acoustic instruments, such as nylon guitars.
  4. Right to repair and durability. This is big to me: since Ollo is not a soulless large corporation, they can be bothered with providing the actual frequency response test printed on paper and hand signed by the technician. They value the money people spend on their products, also offering a 5-year warranty. A section of their website is dedicated to shopping for spare parts:

    We strongly believe that modern products should be designed with serviceability in mind. Any and all spare parts must be available and exchangeable with home tools. Ollo

  5. As I’ve tried them on for hours, mixing and listening, I can report no ear fatigue, which is precious.

Other reviews

Unpacking, test, a bit of technical details and a funny comparison against the Sennheiser HD-600 by London-based mastering engineer Streaky:

A more detailed and technical-oriented analysis by the Noise Floor channel. I’ve been following Brandon for years and as a long time Ollo user, who were working with the previous incarnation S4, he’s thorough and precise:


The amazing discount, coupled with the opportunity of paying in three instalments, made this purchase the best for the year — including 2023 as well.

S4X reference headphones by Ollo Audio

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