Selling my Ollo Audio S4 — Open-Back Reference Headphones (Excellent Condition, Brand New Earpads)

Handmade in Slovenia, quality-tested by mr Gulič himself, this Ollo Audio S4 is an open-back reference headphone built for musicians, producers, and engineers who want an honest, neutral picture of their mix — not a hyped-up "fun" sound. This listing comes with brand new replacement earpads already fitted, so you get all the comfort and hygiene benefits of a fresh pair, paired with a well-loved, fully functional set of cans. You can also see from photos the two optional red pad that can be installed for adding a small shelf filtering on higher frequencies.

Why people choose the S4:

• Open-back design for a natural, spacious, non-fatiguing listening experience — great for long mixing/mastering sessions
• 32 Ohm impedance — easy to drive from interfaces, phones, or headphone amps, no dedicated amp required
• Handmade build with walnut ear cup surrounds and a stainless steel headband — genuinely unique look and feel, not mass-produced
• Fully serviceable design — Ollo sells individual replacement parts (pads, cables, etc.), so this is a headphone built to last for years
• Detachable cable for easy replacement/servicing
• Screw-on 6.3mm adapter included for studio monitor use
• Individual frequency response chart included

A couple of honest notes from the community:

• Being open-back, sound leaks out — not ideal for tracking or shared spaces
• Frequency response is generally praised as flat and trustworthy for mix decisions, though a few independent measurements note a mild low-mid emphasis — worth factoring in if you're extremely picky about lab-measured flatness

Bottom line: a reliable, honest reference tool from a passionate small manufacturer, now with fresh pads so you're not starting your listening sessions with worn-out foam.

Condition: Excellent — light use, fully functional, earpads brand new
Includes: Headphones, cable, 6.3mm adapter, pouch, red filtering discs, user manual, frequency response chart.

See the old, broken and discarded earpads due to wear. Brand new replacement earpads have been included and installed (40€ value)