Oops. Forgot to do the measurement yesterday. If JARBLUE is correct then the db difference won't be significant. However, the sound is damped down and you can have a normal convo in the car (tested with a 350z friend of mine). Stay tuned for the db numbers.

Here are the screen shot of the DB reader I took just for you peeps :) Btw this is not the same reader that I initially used, but it gives you a good hint for how noisy the car is now.

http://imageshack.com/a/img911/9419/WQ1VGl.png

http://imageshack.com/a/img661/3361/NpqDkv.png

http://imageshack.com/a/img538/3904/6puhLQ.png

http://imageshack.com/a/img912/5759/RNGrYg.png

So an increase from 20 to 59? :ugh2:

Love how they spelled breathing.

Lmao. I just noticed the brething xD. Anyhow, no man, it didn't increase, when I did the initial testing it was with some iOS sound meter app. This one is Android sound meter. I might borrow iOS just to confirm the numbers... I guess :)

Use one app and report back please

Just did. Using the same app for before and after.

When idle and the car is warm:

Before: 23-28 DB
After: 18-25 DB

As you can see the DB difference is not significant, but you can hear/feel that the car is isolated and the exhaust sound is toned down/muted.

Anyhow, I'm happy with the results and would recommend to anyone to isolate their trunk if they have noise issues. I would suggest cheaper solution than Dynamat, if you can find one. :icon17:

How about a road noise test?

Too late for the before number.

As cooltoy said, it's too late for that. However, I've applied dynamat only where most of the noise is coming from - trunk of the car. Road noise didn't bother me before, but I'm sure if you want to significantly reduce it, you'll have to take off the carpet, door panels, trunk panels and apply some form of isolation. As I said before, my exhaust noise in the car is more tamed right now.
Keep in mind I have stock headers, HFC, and the full Tomei exhaust. I can't wait to see what my car will sound with the Z1 headers and TPs.

3-5dB difference is very noticeable and significant. good job :tup:

Cranzy my understanding from researching this stuff is that it is mainly for vibration and as such does not need to fully cover every panel are you able to comment on this. I am also under the impression that a proper sound insulation rubber mat would cut down sound more than what you have achieved?

I'm under the impression dynamat isolates in such way that less noise can pass in or out through it. It is usually used for better sound performance inside the car, but it also cuts down road noise and such.

I haven't tried the rubber mat because I didn't have the energy/patience to put another layer on top of what I did. I would assume it will give you better isolation though since the factory OEM mat doesn't go past the strut bar. ;)