For TOP it is just that, TOP, the word. Some fans do say T.O.P but.. not very often and when they do they usually get called on it by other fans because really, in Korea no-one says it like T.O.P. That is only used in songs.
In Korea it's either TOP, when they are purposely pronouncing it or 'Tabi' (sounds kinda like Toppu but softer), which is what they call him 'naturally' because TOP is requires just that tiny bit more effort to pronounce.
I have no idea if I just made sense there but.. Simply - just say TOP. xD
Daesung, is Day-Sung. Simple.
Daesung is actually written like Daeseong so I don't know if that helps you. The 'seong' is a different sound from 'sung' but only slightly and most fans just use 'sung'. Especially if they don't know any Korean.
Try saying 'sung'. Now try saying 'song'. Now try and mix the 'u' sound and the 'o' sound together. That's what you'd looking for here.
Seungri - Soong-Ri ('oo' like hood/food/good etc)
Haha, other people?
Okay, SuJu.
(After starting writing this I decided to point out here. A LOT of names/words are romanized with the letter 'u' when it's actually written with the Korean character 'eo'. The 'uh' sound it implies and the 'eo' sound ARE similar and it's often written with the 'u' simply because that is more natural in English than seeing 'eo' in a word. Just keep that in mind. Knowing how to make that 'eo' sound will really help you. :) )
Eeteuk - Ee-Took (I know loads/most people write his name as 'Leeteuk', including TV shows (like MuBank etc) but the 'L isn't there. Ever. It's not pronounced and it's not there when his name is written in Korean.)
Heechul - Hee-Chawl (it's the same 'eo' sound in Daesung > Heecheol)
Yesung - Yae-Sawng (Yeseong. Again, the 'eo' sound) (Jongwoon btw, is exactly as it seems to be. Just Jong-Woon. Don't make the 'W' too obvious though.
Kangin - Kang-Een / (Youngwoon - again, is exactly as it sounds. And again, don't make the 'w' too obvious)
Eunhyuk - Ooon-Hyawk - Again, the 'eo' sound > Eunhyeok. The 'Eu' .. you make the 'Ooo' sound but without aking you're lips into a circle. Make sense? Try saying 'Food' like normal, making the circle with your lips. Now say it again without doing that and it's as if you can feel the 'oo' sound on the top of your mouth right? Thats the sound you want here. Still the 'Ooo' sound but not overly pronounced.
(Hyukjae - is exactly as it appears, also. Though again with the 'eo' > Hyeokjae)
Donghae - Dong-Hey
Sungmin - Sawng-Meen (again the 'eo' sound
Ryeowook - Ryaw-Wook (You kind of have to run the 'y' and the 'aw' sound together. Like, it's not 'Ree-Yaw-Wook. You shouldn't try overly hard to pronounce the 'y'. If that makes sense..)
Kyuhyun - Kyew-Hyawn (The 'yu' sound is ust like 'You')
Siwon - She-Won ('Si' is always pronounced 'She' when it's at the beginning of a word. The Won is pronounced like the currency, NOT like the word 'won' (as in "I won the race"))
Kibum - Key-Bawm (Kibeom)
Shindong - Shin-Dong
Hankyung - Han-Kyeong (I'm hoping you've practically mastered the 'eo' sound by now xD)
I'm not sure what other groups you're interested in or I would try and help out with some more names but I don't want to make a list of names of people that you don't even like so.. If you want any help with this (names or whatever) you can message ma. I'll be more than happy to help as well as I can.
I hope at least some of that was understandable and helpful. I'm not so great at explaining things, I don't think.
(I apologise for any and all typos. The spell-check isn't working for me.)
:)) ♥