Any song will play effortlessly. Mids are clear and treble is also good, Bass is good.

I connected it with questyle m15 bang on.

Just the right amount of treble...extra clear mids(u can hear each n every instrument...it is a detail expert)...and right amount of boosted bass to make it enjoyable !!! Does justice to all fenres of music. Using it with fiio KA5 which just gives it a wider soundstage and textured bass...makes it better than with ibasso dc06 which is more clearer...but very close n intimate which i dont prefer. Using it with spinfit w1 which gives better fit and comfort... as the stock tip are quite stiff causing discomfort. Love the monarch mk 2 :D

This is probably the best iem I’ve ever heard
20 hours of burn in will open up the drivers,
The sound is neutral, feels airy, I’m totally happy with the purchase .
Thanks to Pritham for suggesting me this gem🙏

This IEM will stay with me for a very long time. Superb for daily listening and also an excellent refrence point for premium IEM's.

I have been using these daily (5+ hours) for more than a week now. It took me a few days to truly realize what a marvel these Monarch MKIIs are! Read on.
My setup includes using these on my laptop via my iFi Audio - ZEN DAC V2 and iFi Audio - ZEN CAN Signature HFM (Amp) via the 4.4 balanced output as well as on the Quedlix 5k DAC-Amp via the 2.5 balanced output. Source: Apple Music, Youtube Music (Premium).
You can run through these excellent test tracks to examine various aspects of your headphones/IEMs and trust me, you will see your equipment’s capabilities in a new (and hopefully good) light after that. https://www.whathifi.com/features/10-best-tracks-to-test-your-headphones OR https://hifigo.com/blogs/guide/7-best-tracks-to-test-your-headphones-and-in-ear-monitors-i. Btw, I think the Monarch MKIIs slayed all these tracks and it was difficult for me to fault it anywhere. You can of course find faults if you search hard enough but then as a consumer, you listen to music for enjoyment and not to look so hard for faults (with a microscope).
An important observation- for me, the Monarch MKII’s sound quality improved a lot after 2-4 days of usage (daily 5+ hours). Everything became more pronounced, tighter, clearer, separated, and airier. The in-ear fit also improved for me as the days passed. I am using the ‘S’ foam tips. I also note that if you’re using these IEMs over Bluetooth, LDAC is your best bet for exploiting the full potential. The iPhone's AAC is just not good enough over Bluetooth.
Physical aspects: As my first flagship IEM, I initially found the size to be a little bigger than usual. I was not used to this category and type of IEMs before. However, after use, I see that it sits fine in my medium-sized ears offering long (3+) hours of listening sessions with comfort. The passive sound isolation is also very good with low (20-25%) volume music being enough to mask any sounds that still trickle in, including human voices. The build quality is superb, and the cable is something you must see and touch to understand! Basically, one can carry around and use this with confidence. No flimsy or delicate parts, wires, jacks, or joints on this one. The case is also spacious, well-built, and on the larger side. Do note that the IEMs themselves are very delicate and handle them with care when picking them off or placing them on tables and other hard surfaces.
Sound Quality: The sound quality is very impressive! Many times, it's as if it has almost entered open-back headphone territory (I own the Hifiman Ananda too). All this coming in such a small, pocket-friendly, and portable package is mind-blowing! You cannot carry a full-sized open-back headphone during travel. But carrying this IEM is surely an option and it helps to get sound quality so much closer to open backs.
The sound is not overly analytical/critical or flat. It has the right tuning to give a fun but natural sound. It’s the kind I can listen to for hours. The bass is hefty and good, but never overpowering. Mids. are well-presented and very visible when they must be (vocally intense songs). Treble and clarity too are very nicely presented, but never harsh or sibilant. Layering and separation are also very good - complex tracks with busy passages having excessive multiple instruments playing simultaneously are delivered well. The soundstage is average though – it is more of a ‘most sounds coming from the left & right at shoulder width’ case. In some tracks, you will feel the base at the jaw while the treble is a little higher. But it’s never the kind of soundstage that will make you look at the door when you hear a knock in the music/movie. The sounds keep around (mostly left-right) and close to your head.
Additional observations- the Monarch pairs exceptionally well with the Quedelix 5k DAC-Amp. The sound is at another level! This works so good for a portable setup in the house as well as while traveling.
One more thing- make sure you talk to Pritam from TAS once before you finalize your purchase. Explain your music preferences, likes, and dislikes to him. He is knowledgeable and hence guides the purchases very well.

This is really good IEM. Very sturdy IEM. Little more bass for my taste. Clean mids. God spacious sound stage. However I find Fiio FD7 much more dynamic, with right amount of bass, more cleaner, holographic imaging and good soundstage. This could be just personal choice.