I am a lover of full bass and well implemented single DD sets. I did not expect much from these - perhaps "good tonality for the price, but poor technicalities" like we expect from these budget sets that have been well tuned.
The Chu doesn't turn my head for example.
Put some wide bore tips on these (Whizzer SS20, BGVP W01, Tenmak Whirlwinds) and get ready for VERY well controlled and textured bass in large amounts - but also expect all kinds of detail without ANY harshness. Mids are solid for vocals too. Timbre is excellent. There is a very slight graininess which is the only con I can think of. Stage and imaging are well above $20.
This might be the best "V" shaped tuning I've heard.
I'm personally not a fan of the appearance, but I'd say these are well worth $100 yet alone their asking price.
Warm V-shape with plenty of details and good technicalities? It's right here. For far less than it should cost.