Guys,
Perhaps I can help here, as I have some knowledge of the work done on F-35 noise issues.
Courtney and gr4techie are quite right to point out the issue of the logarithmic scale used for noise measurement. It's a complex area, and made more complex by the many scales used, not just 'dB', but also the more commonly used (and slightly more accurate) 'EpNdB', which is 'Ear perceived noise in Decibels'.
The real problem is not that the F-35 is significantly noisier than any 'legacy jets'. It's not. The key issue is that the programme's initiation coincided with the application of more stringent noise protection regulations in both Europe and the US. In a nutshell, the customers are no longer willing (or legally able) to tolerate the levels of noise exposure they happily accepted just a few years ago.
Because of this, the F-35 programme has done more work than any other in getting the best knowledge of the actual noise generated in all operational scenarios, including cat launches, VLs, and STOVL launches. Flight decks and ships pose a special challenge, because you can't keep personnel as far away from the noise source as on a land base.
Knowing the noise levels is also important in designing aircraft structures that are exposed to even higher levels of sound energy. Those of us who struggled with cracking Harrier heat shields and failing wiring know what 'acoustic damage' can entail.
The F-35 is as noisy as most other jets generating nearly 40,000 lbs of thrust from low bypass engines. There are some jets that are louder, and some quieter. The programme's predictions and measurements put in around the middle of the pack, but as I've explained, the incoming noise regulations led to a number of special programmes to assess all possible solutions.
Active noise reduction and more intrusive (in-ear) designs have made ear defenders better and better, but there are drawbacks, including problems in keeping the ear inserts clean and properly fitted. The next step could include larger helmets that reduce noise transmission through the skull - some of the designs were scarily similar to the 'Judge Dredd' model. Other solutions include reducing the noise exposure over time - at one stage, the CVF team were looking at 'acoustic shelters' around the flight deck to give crew some respite from the noise.
Bottom line is that managing noise exposure around high powered combat aircraft is a tough nut to crack. It's tougher on board. And the new regulations have made it harder still. But there are some extremely smart people working the issue.
Hope this helps
Best regards
Engines