Sound impressions - unfortunately I have never listened to a Lotoo source before so can't comment on similarities there. However, I think the tonality of the S1 is similar to what Sony does - more organic and fluid versus sharp and technical. Not talking night and day difference but I think it's fair to say the S1 goes with more musical than technical. As for a more apples to apples comparison with DFR here are my comparisons:
- DFR has more sub bass and top end sparkle. However, I wouldn't say that's a good thing unless you want a "U" shaped FR. S1 is more neutral which gives a better balance to the mids.
- Sound stage is pretty decent on the S1. You get nice 3 dimensional sound, but smaller overall than higher end devices. DFR on the other hand is very intimate and pretty much just 2 dimensional.
Now here is the interesting thing - the above notes are playing compressed AAC files because that's how I intend to use the S1 with Apple Music and Netflix. Honestly on the DFR I can't tell the difference with AAC or lossless most of the time. With S1, when I tried with my lossless library and bit perfect player (Audirvana), it's like I'm listening to a different device. Everything is just more:
- Sub bass goes really deep with control and texture.
- Mids get a touch more detail in the upper frequencies
- Highs get more separation and detail, but still remain organic
So in brief, the S1 most definitely scales with better player software (bit perfect) and lossless files. I think the player software is the bigger driver though. I would highly recommend folks give this a try with a premium player - JRiver, Audirvana, Roon, Foobar, etc. If Lotoo eventually provides an ASIO driver for Windows, even better.
S1 is the best dongle I've owned so far with COZOY Aegis and DFR being the other 2 and still have those. I am a fan of dongles for the ease of use and negligible drain on portable device batteries. When you consider cost, S1 blows away the competition. I'm curious how the Cobalt compares but at 2X the price I can't imagine the performance ratio is better.