No, not harsh, It reminded me of the sound of my old ADS monitor speakers - - a little high bass heavy and a higher mid treble. A after about 100 hours, the mid and lower bass cleaned up, and and the sound gradually became linear and without any forward-sounding output in the mid tones and treble. I might not be saying this correctly, as I'm not used to the audiophile lingo for describing sound. All I can say is that at around the 300 hour point, the sound became linear from low bass to upper treble, without stressing any band of frequencies. One thing: Some speakers will "wear" on you after a couple of hours, the 2.7s do not. I can listen to them for hours at a stretch without becoming irritated. For me, the capability to enjoy protracted listening without becoming fatigued is the hallmark of an exceptional speaker.
I usually listen in the late evenings via my STAX Lambda Pro headphones , and I'd say that the sound of the 2.7s closely replicate the Lambda Pros from around the high 30 cps to the 12,000 - 15,000 range. My Pros go both higher and lower.