Sound deadening on the cheap!

 
Passenger floorpan was as clean as the drivers side and free of any sound deadening.
The car is completed as far as this work is concerned.
The difference it has made to the car is staggering. I do not exaggerate.
I bought a pair of tweeters after learning on here that the car was alteady wired for them.
I think I was the first person to remove the door cards as everything looked original. It was then I noticed the lack of sound deadening and the two crash bars against the doorskin. It set me off on this journey.
Total cost for 4 rolls was £66. It has lifted the car in to another league.

Conclusion: 
1.The doors are the biggest vibration source. Doing those first and the effect it had on the car spurred me on to do more.
2. The floorpan is next as it is a huge area that is inside the cabin. It has cut down on road noise and it just feels like a better quality of ride as suspension bumps aren't transmitted inside the cabin as much as before.
3. Behind the seats. Covering the tank panel made a difference. Not as big as the first two.
4. The engine cover. It is already covered by the "dead dog" insulation but it did help.
5.Under the bonnet. Not sure if it made any difference. I figured anything in front of the ears must help but can't quantify really.

There was a secondary benefit for me. I have only had the car 2 months and I am getting to know it. Removing the seats, carpet etc. allowed me to see the condition of the car and how it is built. I am definitely the first person to remove the seats and carpet as there was not a mark on any of the fasteners. I now know how the boot/throttle cables are run and the loom too.
I like the car. It will be my last classic build and I will get it how I want it when funds allow but I can't help thinking that anything I do will just make it better...rather than modding it and still having a rattling car!
I encourage others to try it. The car has a very capable chassis and now it's a quiet and enjoyable chassis too.

A great report, thanks for your coverage & running commentary
Why I experimented originally is lost in the fog of memory or lack of it, other than to say having evicted the dead dog & before the reconstituted foam, I tripped over a half finished roll of the stuff, left after spending a jolly few hours trying to stop a drip from the extension.
Inside the doors got a do due to the cards being off, it never occurred to me to file a report of my findings, so thank you for taking up the batten & running with it.
M

@Airportable

Thanks...I appreciate your comment.

It was actually your "by the way" comment in another thread that triggered what to use.
I too had used some on a flat roof and applied bitumen over the top. 
So when I saw the inside of the doors it drifted back and prodded the grey matter.

The most important thing is it truly improves the car as you know from doing your doors.

 

BTW..each roll weighs 2kg...so 8kg's or 20lbs in old money. 

I agree with this assessment but would add that it is worth to do the boot, including the floor and lid. The most noticeable difference will be when you close the boot lid! You can also somewhat access the inside of the rear quarter panels and put a piece in there (similar to doing the inside of the doors but even tighter). 

While I have not done it, I wonder if it makes sense to put a piece inside the front fenders (after having removed the plastic fender covers).   

Thanks for the tip about the boot.
I ran out of the roll but I plan to get another one because I will be changing the door speakers soon and want to add some to the inside of the inside panel. I know that will be fiddly but it will be the icing on the cake.
I had also wondered about behind the carpet on the boot side panels so I will follow your advice and put a strip in there.
It doesn't need to cover the whole panel just needs to deaden the vibration.
I am also certain putting it on the inside of the fenders will help especially with suspension noise. I am planning on having a roll available for whenever I go in there.
I am also suffering from the detached carpet in front of the door! Thanks for the foam idea, I know that someone used underlay to lift the carpet up there and it worked too.
The job has really made the car more enjoyable and uplifted its status!

For the record, and those contemplating doing something similar.
i went for a test drive in a MGB GT that had been re built by Frontline Developer and fitted with modern engine and gearbox and all sorts of other goodies. I wanted to see if the rear suspension mod was worth it.

When showing me round the factory they pointed out the sound deadening (I can look back if necessary to see which brand). It had obviously made a good impression on me as the car was very quiet.
Flushed with that thought I lined a MGC before I had to sell it and also added some foam insulation too.
As far as I can remember it made very little difference compared to the MGB that I have now that has felt like material under the carpets.
In my opinion it is more of a science than one might think and getting the right materials in the right places is very important.
Stopping vibrations by adding pitch backed type materials might stop vibration but to really dampen noise down there is probably nothing much better than the “dead dog”.
Years ago (decades) I fitted some old foam backed carpet into the load space of my small van. That made.a fantastic difference in audible comfort.

Sound deadening and sound proofing are indeed Science. Acoustic science is very complex. I am a musician and I have a small studio that I had to treat for standing waves and indeed soundproofing.
Whilst I can't speak of the science of bitumen backed tape I can speak of the effect it had on my car.
It is dramatic.

  Im sure that given enough time the carpet would escape the car all together, so insistent is it to shuffle about.
Earlier carpets were difficult to pin down, later ones with the moulded backing are an improvement. I suspect earlier ones were modelled on the shirt lap hanging out of the pants worn by Plug from the Bash Street kids.
I made a couple of retainers which screw into the inner sill; when tucked under the door rubber they retain the carpet snugly.
These are Perspex & the MG badge is off the MGB Rostyle wheel centre cap, I stood the badge off the plate & made a ring of blue LEDs which illuminate in sympathy with the footwell lights.
These come under the heading of five minute fixes, from inception to final item took about a month.
M

 
I’ll include another picture, although the effect is Ok the outline of the Perspex could be improved.

They is handsom'..bobby dazzlers and a great solution.
By the way..I hate to admit it but I remember Plug and his jumper up his chin...I also remember the Floggers that sometimes came in the comic!

I like those carpet retainers Mike. Seriously would you consider making a pair for me please so long as you charge me enough to make it worthwhile you doing so.