I keep an eye on the FiOO brand and three FH1S, FH3 and FD3 models. Or maybe some alternatives? I don’t care much about powerful bass, more about vocals.
What’s your budget?
I am as well is fond of vocal quality.
Tea2 - first impression for me was the forward vocals with good sub-bass.
KL - smoother forward vocals w/ wider soundstage and heavier notes.
I love both of them because of the vocal quality 
Maximum 150$
Olina might be a good choice if you’re looking for vocals over bass. Also, since it’s just over your limit and can be had used or on sale within your limit, the Shuoer S12 might be a good pick as well, so long as you aren’t extremely treble sensitive.
Hopefully someone can come along and offer some more suggestions. I haven’t heard much up to that range to make a rec. My only close suggestion would be if you can up the budget by $25-30 look for a used SeeAudio Yume Midnight. Bass to midbass isn’t powerful in comparisons to some other choices. It does have a nice subbass lift that would help for PsyTrance and vocals are clean and well presented.
I enjoy a good mix of Goa and Psy and found the Yume to be fun. I only parted with it because of fit and other IEMs in my collection got more use. Unfortunately that’s really all I can rec, from what I’ve heard, that possibly fits your criteria and comes somewhat close to your budget.