Ollo Audio Studio Headphones Review and Impressions Thanks to Ollo Audio for providing this upcoming loaner. They sent their two headphones, S4X REFERENCE (open back) S4R RECORDING (closed back) S4X Reference Comfort The are very light and the suspension headband quickly adjusts itself to a comfortable position. The ear pads are a little small, they didn't bother me but could be an issue for others. They also have pretty strong clamp. I imagine the clamp is adjustable by bending the headband but I'm not going to bend a loaner. I find them comfortable but my head is a little narrow. Sound I think they have good synergy with my iFi micro iDSD BL and focused my listening there. They have good clarity, a smallish sound stage, and good timbre. The FR is tuned a little bright, probably the upper mids, they sound brighter than the OG Clears (from memory). I wouldn't call them harsh, simply tilted. Both versions are bass light and have extended highs. Their sound isn't as rich as the Yamahas or HD 6XX though I wouldn't call them dry. Considering my collection includes 2 ZMFs (and plans for a 3rd), I obviously prefer some richness to my sound. Open vs Closed The tuning for both is very similar. I was pleased to see the closed version doesn't have boomy bass. I think the open back has a smidge more air and bass extension while the mids and low end are more elevated in the closed version. It's not a large difference, depending on the music I sometimes had to listen carefully. Out of iPhone They sound quite good directly out of my iPhone 11. I prefer the iFi but the convenience is nice and for some music the iPhone gets around 80% or so of the way there. Other times it was more like 60%. Minor nitpick: the cable is microphonic. S4R Recording Comparisons All comparisons done on 2016 MBP -> iFi micro iDSD BL vs Yamaha HP-1 Anisotropic Yamaha: Smoother Sometimes more veiled, less air/space Richer, cozy, fuller sound Tone more to my taste Voices more elevated A bit more refined Ollos Better clarity Brighter More extended top and bottom Timbre is close, the Ollos is a bit better Resolution is close, I think the Ollos resolve a little more vs HD 6XX Sennheiser More veil Smoother A little richer More sleepy On the iFi there was no winner in resolution though we all know how well the 6XX/650 scales ... Ollos Better clarity Brighter Better slam More lively I had a friend over earlier today and she also did some comparison listening. She found the ear pads a little small and shallow but otherwise found them comfortable. She enjoyed listening to music on both Ollo models much more than the HD 6XX or Yamaha. She plans on buying a pair and seeking larger ear pads for comfort. Final Thoughts I found the Ollo headphones enjoyable and a strong contender for their price range. If you find the HD 650/6XX tuning too dark or want a different flavor, I'd recommend getting on the upcoming loaner.