Earpiece replacements ALWAYS CRACKLING top speaker

hi, i've got about 5 HTC One M8's and all 5 of them have been refurbished, the earpieces were damaged & replaced and each one in all 5 phones is crackly even at low volume, ive spent near £40 on new pieces to no luck, its as though the "driver" is touching the frame or something else within...

ive spent hours studying it, "experimenting" from frame cutting to earpiece module cutting.. i cant afford this no more

the repair shops say they have fixed it but it comes back worse than i gave it them..

i have a genuine used M8 which the earpiece was perfect but had a spungey like adhesive, of which every replacement doesnt have, instead a tape like sticky

now then, how the F do i get them not to crackle, is it because it needs a cushion "foam adhesive" between the frame or simply just a secure gap from the frame...

the sticky tape adhesive when fitted only induces poor sound and crackling

it only seems to be the top speaker as the bottom one has a housing shell prebuilt into it.. it never seems crackly

also there is a soundtrack i found of which the crackling is very audible though most phone can handle the track, link below

https://www.youtube.com/watch?v=YIY8aKg4...

any help appreciated whatsoever...