SoundBlock or normal plasterboard (drywall)

Hi. I was intending to use 2 layers of Soundblock plasterboard (drywall) as it is more dense than normal plasterboard. However, it only comes with a tapered edge, as oppose to Square edge. I didn't want the extra work of filling in the tapered edge and sanding smooth before applying the second layer (I am assuming that this WILL need doing, otherwise there will be a slight gap left between the first and second layers, due to the taper). Therefore, I'm thinking of going for two layers of normal 15mm Square Edged plasterboard. Is this a mistake ? How much better is SoundBlock compared to normal plasterboard ?

Dunno, what's the density of the material? Plastering needs to be done anyway and it'll only take a second once you get the hang of it.

Standard 15mm = 9.8 to 11.0 kg/m² SoundCheck 15mm = 12.5 to 13.1 kg/m² Is it worth the extra hassle and cost in terms of costs and extra work ? Will it make much diff in terms of TL?

that would be about 850 kg/m3 That's just a bit more than standard GB indeed. Not that much tho. If it's way more expensive, I wouldn't spend a dollar more on that. Else you might use it, sure.

Add another layer of regular plasterboard. Much cheaper. I used regular plasterboard on my 1st room and all was well.