So I just got my sound deadener today and will hopefully get a chance to put it on tomorrow. I’ve never installed sound deadener before so I’ve searched YouTube videos and see some people covering every square inch and some people just kind of patching different places. I want to focus on my trunk lid since it rattles the most so any advice on placement and what I should and shouldn’t cover or need to and don’t need to cover would be much appreciated.
The people who do full coverage do it for 2 reasons
1. They are using low quality deadener that has weak properties. They think there saving money by buying cheap deadener but if you have to apply 3x as much to get the same acoustical deadening properties then your not really saving money
2. They think deadener blocks sound which is doesn't. It helps prevent the panels from vibrating (reasonance) but it doesn't actually block noise. They think "oh if I do full coverage i'll block the noise from coming it" when it doesn't work like that. You need something like MLV
In regards to your trunk if your using a high quality deadener then at least half coverage should be fine. You eventually get to the point of diminishing returns. Think of it like a drum cymbal, if I apply 25% coverage to the cymbal and then hit it with the drum stick the cymbal will hardly make any noise. Me adding 75% more coverage to that same cymbal might make it 5% quitier if even that