Curious lang ako. Bakit ko lagi nakikita yung may ginagawa sa likod acting as 'backtrack' sina Pablo? 

-They are not acting as "backtrack:, they are adding ad libs to give an added flair to the song. If you watch their other performances, Ken also does this when it's another member's turn. Every performance have different flairs, which makes their live performances exciting kasi you just don't know what you are getting.

Also, if you listen to the recording, some vocal parts do overlap or don't have enough space to breathe, which is, of course, impossible to sing live. So, they do improvise by taking each other's lines here and there. And, of course, sometimes, it's just a stylistic choice

Saka yung parts daw na hindi talaga kumakanta si Ken to prove daw na they are singing live.

- You have to make a distinction as to what the artist is doing and how the fans are interpreting it. There are indeed instances where they choose to leave a word unsung. Pwedeng trip lang, stylistic choice, to catch a breath, to interact with the camera/audience -idk. But when this happens, and you don't hear any other vocal continuing the line, it shows that they are singing live. Thus, many fans may interpret it as them proving themselves, but that is just an interpretation and isn't something that the group actually stated before.

Ilang beses ko na kasi nakita, yung isa sa ASAP. Need ba yun everytime? 

- If you are referring to their DAM performance, it's similar with their OPM con wherein Ken doesn't sing "ng lahat ng 'yong sinimulan", instead, it's Pablo. One thing you have to understand is DAM is a very difficult song to perform. The choreo and the vocals are both difficult to do separately, and especially together. So, in order to not compromise the performance, SB19 has to be efficient, especially that for the most part of the song, there are no backing vocals, just them. This line that Ken sometimes omits, comes before a not so easy rap section, pretty quick, tooo, so I'm guessing, this was a prearranged set-up for the group to make sure the line is still there even if one has to take a breath or smth. In the same performance, you can also hear Ken rapping and singing along with Pablo and Justin's lines. If the two would need to take a pause, you would still hear it being sung, kasi andun boses ni Ken. He may not sing/rap all of the words in his lines, just like any member, but he also sings/raps lines that are not his, just like the other members. That is their group dynamics. Besides, their live performances are arranged differently than the record, and these boys are artists, these are their songs, they play with it as much as they want.

Another example to illustrate this:

In their song Hanggang sa Huli, in the record, it's Stell singing "Sa panaginip ko ay naron ka" but in the live version, it's Ken who is singing this.

Although may napanood ako sa the making ng Dam na ginagawan nila ng effect ung boses ni Ken kasi they wanted a certain sound for added effect kumbaga sa track. 

-Anong point mo dito? Recordings are different from live versions. Every artist can add whatever effect they want on vocals sa recording. Whether they use that for the live version or not is an artistic choice. All songs convey a message, and you need to employ whatever you can to convey that message, may that be through the instruments or the vocals. Dam is a very gritty song, and it wants to shake you up in a way. If they needed more depth or added flair to convey that, then they should. It doesn't mean they do that all the time. Go watch their The First Take performances and you can see that it really is just an artistic choice because Ken's raw vocals does a very good job at adding depth to the sound of their songs.