OK. Leo is speaking here.
Recently, I've had many customers who are wondering about the differences between the Final Satin and NYC Proto, as well as the differences between Satin and AOO. As I am part of the tuning of Satin, I believe I am the best person to answer these questions.
1. The FR measurement of Satin/Satin Proto.
First, I want to apologize. Yesterday, I shared a screenshot of the final Satin's measurement with a customer, but I forgot to remove the 1/12 smooth, so it looks a bit lumpy. Now, please use this graph as a reference for the future.
Satin vs. NYC Proto Aligned at 1 kHz
After the CJ NYC, I collected a lot of feedback from audiophiles, and I spent extra hours with the prototype. I noticed a tiny metallic sound coming from that prototype. So, I asked John to go through the entire FR spectrum step by step to identify where that metallic tone comes from; then we found it — 9 kHz. We rearranged the treble layout and driver placement to eliminate the 9k peak.
However, my concern was that if we tamper with the treble too much, it will affect the engaging signature, the amazing instrumental texture, and the clarity of the treble; Satin will no longer be Satin. Thanks to the brilliant John and his decades of experience in acoustic treatment, he raised a point.
If we control the peak energy of the treble and reduce the sustain of each note in the treble a little more, it will give us better treble definition and a cleaner treble attack, problem solved.
Now we can look at the spectrogram comparison:
NYC Proto:

Final Satin:

As you can see, we basically reduced the peak energy by about 5% and also reduced the duration of the peak energy by about 10% in this specific frequency range. John fine-tuned the treble duct like a surgeon, and also replaced the entire capacitors and resistors until he achieved this point.
Satin vs. AOO Aligned at 1 kHz
I heard some audiophiles stating the similarity between AOO and Satin. I was sincerely shocked. Because to my ears, the only possible commonality between these two amazing IEMs is that they both have great bass quantity and quality. However, upon seeing the graphs, I now understand where the question originates.

They both share a similar W-shaped sound. However, the way we treat the timbre/texture and the overall sound is entirely different.
Satin Spectrogram

AOO Spectrogram
Again, in the mid, upper-mid, and treble ranges, AOO used an approach to create longer sustain, resulting in a much airier and laid-back sound. Saitin, on the other hand, offers shorter sustain, resulting in a cleaner, more revealing, and more physical texture. I think everyone who has tried both IEMs will agree with me on that. This leads us to the third topic — Planar vs. ESTs.
3. Planar vs. ESTs
At this point, some of us should have heard the treble and ultra-high frequencies from both types of drivers. In short, the ESTs are known for more air and better extension after 14k. Well, planar has a faster response, thus sounds more physical and has a harder attack. John and I both have a long time of experience playing actual instruments. I dare call myself a musician, but John certainly is or was. As the first collaboration between the two parties, we aim to showcase our genuine expressions. We know it could be a little risky, as the larger market is less familiar with the planar timbre and texture in the IEMs. However, we are willing to take it because we love the authentic texture of this
Silken Planar so much. What is unique about this specific planar driver is that it is very responsive to the changes in acoustics structure, which gave John a lot of space to play with it.
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Side Notes: I saw that a few audiophiles were curious about why there has to be a rise in the upper midrange. Well, this is just my personal indulgence-- a little therapy for my obsession with J-pop and J-rock. If you know me well, I am still playing drums in a J-rock/metal cover band

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Already, I hope this message answers most of the questions. If you are curious about Satin or want to share your playlists for me to test, or anything I can help with, feel free to email me!