Looking for a DAP with a nice built in amp, I recently acquired a new overstock LG V20 on eBay. The few negative reviews I've read of it talk about the ESS Sabre "glare", describing it as either a bright (specifically sharp) frequency response or a sort of digital or unnatural sound. The only other Sabre device I ever had was a Dragonfly Black, and it's too long ago for me to remember anything reliably about how it sounded, though I want to say that I didn't love the highs on that either. Well, I plugged my already bright DT 1990s into my V20 and listened to a bunch of stuff. Especially on things like the 4th movement of Beethoven's 9th which starts out with some high and loud horns and strings, high frequencies on the V20 did indeed sound remarkably unpleasant. The strings sounded scratchy and the horns almost as if they came out of a synthesizer. By comparison, things sounded much better out of my Topping NX4, with a more pleasant and natural tone. Eager to see whether this was expectation bias, I decided to take some measurements with my MiniDSP E.A.R.S. These measurements follow the manual, i.e. use Room EQ Wizard, volume match a 300Hz sine wave at 84dB(C) S, etc. In the past, when I've had developed subjective listening impressions about differences in amps and DACs, I've never been able to find any big difference in my measurements. This time was different! I tested three different scenarios: Macbook USB -> NX4 -> DT 1990 LG V20 -> DT 1990 LG V20 -> Line in on NX4 -> DT 1990 I ran the measurements twice for each scenario to see if there were any major variations between runs. W.R.T. frequency response and impulse response, the results were consistent across the two runs. Full images are available on Imgur. First let's talk about what's not different - frequency response. Yeah there's a slight difference above 17.5 kHz, but I can't hear that high anyway (14 kHz is my limit). What is different (pretty radically so) is the impulse response. Two things strike me about this: 1. The LG V20 has much faster initial decay after reaching 100% of signal 2. The initial response is actually a -13% (out of phase?) before it reaches 100%. I haven't taken a whole lot of such measurements, but I think this is the first time I've seen this kind of pronounced dip. Incidentally I also measured my LCD2C out of the LG V20 and observed a similar dip. Furthermore, if I amp via the NX4, I still see the same dip, so I'm pretty sure it's the V20's DAC and not the amp that's responsible. The faster initial decay seems like it probably just improves clarity. What's interesting to me is that initial 13% dip. My question to those of you who know more about reading impulse responses... Could that weird initial dip in the V20's response be what's to blame for higher frequencies sounding unnatural and if so, might we expect to see similar dips when measuring headphones with other Sabre devices? Is this what the Sabre glare looks like when measured?