iPhone 6S Plus Audio issues: we can fix it! – share phone repair guide and provide phone repair tools (China phonefix team — diyfixtool.com / ecufixtool.com)
iPhone 6 Audio Problem Repair, iPhone 6 Audio IC Replacement - YouTube
iPhone 6 plus speaker and mic no sound solution - YouTube
iPad, iPod, or iPhone Speaker Not Working, How-To Fix - AppleToolBox