Youtube review: Photo: http://dalethorn.com/Photos/iPhone7p/Headphone_Sennheiser_Apogee_Ambeo_01.jpg Sources: iPhone7+ and other iOS-11 i-devices. Review notes: My first impressions of the playback** sound of the Sennheiser/Apogee AMBEO IEM/earphone binaural recorder (AMBEO hereafter) are based on comparisons to other IEM's (Sennheiser IE800, RHA T20, FI-BA-SS etc.), to a few reference headphones, and to notes I've accumulated from many prior reviews. I'll describe how I relate to this IEM (i.e. my personal tastes and how I use these earphones) only after covering all of the objective issues. **Since this review is primarily about the IEM/earphone and its high fidelity sound reproduction, interested readers can find full details about the binaural recording features on the usual commercial sites. I'll just say that it works very well, and when recording it's not necessary to have a perfect ear-canal fit. When recording, the earpieces need to be in their approximate positions in the ears so that the microphones are positioned correctly. Only the playback requires a good ear-canal seal for proper bass and treble balance, since the microphones face outward and aren't concerned with the ear canals. When I first used the AMBEO, recording with the iPhone camera worked perfectly with no special settings on my part - just plug the AMBEO into the phone, put the earpieces into the ears, and start recording. I have some short samples on my youtube site, but of course it's necessary to play those through headphones to hear the binaural sound perspective. NOTE: For me, the sound of most IEM's varies widely depending on the eartips used and how well they seal for bass balance etc. in the ear canals. But, I have a good sense of when I'm getting the proper ear-canal seal, by pushing the earpieces in until the treble drops noticeably, then backing off until it pops back in - crude but effective. I won't try to describe an absolute frequency response for this earphone, because of the variability for different users. For users who are curious about that, I recommend checking the headphone test measurement websites for their response measurement charts. What I want to describe are the tonality and musicality issues, assuming of course that the sound is good hi-fi, and the AMBEO is indeed excellent hi-fi. The music tracks listed below were selected to illustrate the strengths and weaknesses of this earphone, so hopefully the comments in that list will point up its most important sonic qualities. My IEM experiences include the Final Audio FI-BA-SS (hard and bright), the Sennheiser IE800 (wonderful), the B&O H3 (slightly bright and a bit lean, but good), the RHA T20 (like the H3), several Soundmagic models (decent sound that varies between a lean bass and an emphasized but woofy bass), the Xiaomi MI-IF Piston (as good as or better than the Soundmagic earphones), the Thinksound USP1, and now the AMBEO. Comparing the AMBEO to the USP1, the AMBEO impresses me as very neutral, compared to the "v-shaped" signature of the USP1. I can't say much more about the flavor of the AMBEO for the reasons listed above, but unlike many headphones and earphones that have a fairly neutral sound, the AMBEO goes very deep into the bass with excellent weight, and the upper treble harmonics are rich and detailed. The AMBEO's earpieces have their microphones on the outside and the eartips are on the inside. The over-the-ear/behind-the-ear hooks appear to be permanently molded to the earpieces, so there's no other way to wear them that I can see. The total cord length from the earpieces to the Apple Lightning plug is ~48 inches, with the control box about 15 inches down from the earpieces. The control box has buttons for start/stop and volume up/down, as well as a rocker switch for noise canceling (ANC) on/off and environmental awareness on/off. The environmental awareness works in changing the background noise level during playback, but I haven't found the ANC to do much of anything. There is also a slide-switch that adjusts gain(?) when recording, but per the above, that won't be covered in this review. In spite of my reticence in describing the AMBEO's basic signature or frequency response, I will say that I like it better than anything I've used since I had the Sennheiser IE800. I prefer a fairly neutral sound, with solid deep bass impact and a sparkly detailed treble that's not bright. I can't compare the AMBEO to the IE800 or any of the latest high-priced IEM's, since I don't have any of those on hand, but I'd be pleased to pay full price for the AMBEO for music listening alone since it's that good. The binaural recording feature is the extra perk that makes this quite the bargain. In previous IEM reviews I've included the following music samples with comments about how the earphones sound with each track. My suggestion is instead of reading each one as an absolute unto itself, you could compare my notes here to those other reviews and see how the AMBEO compares with each individual track.