As you can see from the picture below the fan due to its size doesn’t fit directly over the A4 tube, it over hangs slightly. The gap was letting a lot of air out rather then pushing it into the tube.
Only one this can fix an issue like this, TAPE!
Not the prettiest of jobs but did the trick, we now have no air escaping from the gaps. What has this done for our A4 and its stats?
Amazingly its reduced the dB level by 2.3dB and changed the pitch of the sound to a more comfortable level.
And the temps? Well…. not a great deal, 1c on one of the blades but this could be put don’t to the ambient temps or even the quality of the thermometer in the miner
Conclusion
If your not worried about looks then I think it is worth adding the tape to reduce the noise and a little heat. If you are worried about looks, buy some nice tape and spend some time making it look good.