As announced, here is my initial feedback after some hours of intense listening across a wide range of recordings.
General Impression
The QRONO filter is not an effect filter, but a subtle yet very audible refinement.
Listening becomes more natural, more relaxed, more real. I constantly catch myself wanting to listen to every track until the end – a clear sign of long-term musicality.
For context: I run my system with Acourate DSP linear filters, which align my speakers and room in perfect phase and frequency balance. With that foundation in place, QRONO complements it at the DAC stage, refining micro-details and natural flow.
I will also test the filter without DSP correction and make a direct A/B judgment – to see how QRONO performs both on its own and in synergy with DSP.
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Concrete Examples
• Marianne Faithfull – Madame George (Live Montreux)
→ More live atmosphere, stage rock solid, tones floating in the room.
• Marianne Faithfull – Broken English
→ Intro: guitar on the right rear sounds a bit harsh with Linear Phase – QRONO makes it detailed, present, but never fatiguing.
• Malia & Blank – Magnetic Lies
→ Greater depth, bass more defined, the musical flow feels more logical and organic.
• Mercedes Sosa – Misa Criolla
→ Timpani resonate longer and more naturally, the room illusion is captivating, guitar and flute merge in perfect harmony.
• Musica Nuda – Come Together
→ Petra Magoni’s voice reveals the finest lip vibrations, rolling smoothly in waves. Double bass remains defined, everything feels intimate and self-evident.
• James Blake – Limit to Your Love
→ The deep bass moves clearly and structurally from left to right. No boom, just flowing energy through the room.
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Interim Conclusion
• QRONO delivers more transparency, more depth, more stable imaging.
• Instruments and voices sound more real, embodied, and relaxed.
• The musical flow has a natural logic and self-evidence – free of strain or technical distraction.
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Thanks to Lumin
It’s truly remarkable that a manufacturer offers such a feature as a free update.
Instead of pushing new hardware, Lumin invests in genuine sonic improvements for existing customers. A big thank you! 
For me, without question, the QRONO filter is a keeper.