Sound deadening on the cheap!

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.

I chucked the design & one off builds for third parties into a hedge whilst passing, roof down & at high speed. I never made any money out of that stuff, although I derived a lot of pleasure from the process.
All the time spent on those jobs I planned to dedicate to my own projects; the best laid plans of mice- - etc, I’ve never been busier.
I’ve three jobs which have been in development for months, whilst my own projects fester. I have bright yellow callipers hung up in the garage awaiting fitting, four wheels & tyres in my wife’s greenhouse, I’m moving the window switches from behind the gear stick to the door cards, nothing has moved on these for an age.
If you are willing to wait then I’ll happily make a pair but if you buy some Perspex & have a jigsaw you could rattle a pair up in next to no time. I’ll look back to see what sizes I used & the supplier.
M

Thanks Mike, the perspex supplier and rough dimensions would be great to have

I had a retrospective through my Perspex purchases & found reference to the bits I bought for the carpet plates. The supplier was Trent Plastics & as with all these bits, you will find them on eBay. It was an A5 piece & out of which I cut two, you can buy it in 55 colour combinations & that piece was £3.50. The MG badges were £4.99, I think it was five in a pack from padmg they are for MGB Rostyle wheels. If you want to put a bit of light behind them, you can buy an 8 LED ring these are a couple of quid but you need a controller, which are not much more (see picture). The unit is RGB & by fiddling with the settings you can derive a colour to match your mood. I haven’t used this, I made a circuit board & populated it with SMD LEDs, this wasn’t a success. LEDs too small, hands too big. I substituted those for 3mm devices.
These also go behind the replacement knobs which when modified look well on the heater controls; a set of three are about £7.00. A little modification is required.
I seemed to put you off Chris by offering to make some eventually, yet offering to make a reducer for Delbourt, almost at the drop of a hat 🎩. My lathe is constantly running, with the tools I use to work plastics in their own dedicated posts, cutting sheet requires the bandsaw to be pulled out & sorted, it’s all time, not the time doing the job but the time setting up, stripping down & cleaning after.
I’ll add a picture of a method I used for sheet work before tooling up properly.
I alluded earlier about long standing jobs, I had deliveries today & polished one off & pushed another several steps along. I also went to my granddaughters school concert. 
M

Yesterday I drove my wife's Yaris in to Aberdeen with her ensconsed in the passenger seat.
I have always considered her small car to have a bigger car ride. Quite civilised.
On the way I remarked to her "My MG is actually quieter on the road than this car"
I got no response but I smiled to myself.

I got some scrap underlay from my local carpet store skip and this morning I removed the drivers seat and fitted it.
It cured the carpet fit at the front as another poster suggested it would.
I will do the other side after lunch.
My MG Maybach is coming along nicely...