I recommend that you go back to the shop you purchased your Layla's from. Allow the vendor to "do the right think" if your dissatisfied. I have two very powerful xeon lights (used for detailing exotic cars) and I've used those lights and natural sunlight as well and I have not noticed any air bubbles trapped in the acrylic casing of both IEM's
-Speed
So I went back yesterday and the shop did open up a new Layla stock to see if it's any better (only shot I had as they would only open one). The new one had one iem being almost perfect but the other side having the same problem as the ones I have on hand but in an even worse state. The shop told me I cannot swap the 'flawless' one only as there will be channel imbalance since 'I have burned in' my pair and also JH has matching serial numbers inside and they would know we only swapped one of the pieces in the future should I ever bring it back for maintenance. Thus, I was forced to make a decision between either my pair or the new pair, notwithstanding that both were not assembled without flaws.
For obvious reasons I went into a state of deep struggle as my choice was between 'two evils':
two minor-flawed ones versus
one significantly flawed and the other side okay kind of decision. In the end I kept my pair and only exchanged the cable, since on the 3.5mm cable I had the white potentiometer scale on the bass adjuster was only printed partially and some parts could not even be seen (faded away). The pair I could have exchanged for had no air bubbles whatsover though on the body, so I am still pondering if I should have exchanged.....
In the shop's words, JH insisted to build these by hand and that's why the QC is so uneven and questionable (shoddy), that their (JH) philosophy is that as long as the thing sounds fine, cosmetic defects should not be a problem, a notion I cannot agree with I'm afraid, especially at this price point. I should add that during the unboxing at the shop I received a mini screwdriver with a transparent handle with an end too wide to even operate the variable bass, although the shop instantly exchanged the correct blue-handled one for me so the problem was solved immediately.
On a side note, I also noticed that there were two accounts of printing error, one on the back of the outer box sleeve description ("Recorded by Eric Clapton and released in 1970 on
Layla and Other Love Songs. was
Layla inspired by Clapton's unrequited..." - should be "
Layla was inspired"?) and one inside the owner's manual where the 0 db neutral bass setting was described as being 12'o clock position and not 7:30. Overall, the standard of quality control was not impressive.
I have swapped over to the 2.5mm balanced cable and I now notice noise / feedback / distortion whenever there is playback of heavy treble sounds (e.g. high-pitched piano notes played heavily). I have no idea whether this is because of a bad connection, or a thing of the balanced cable (I have not noticed this with the single-ended stock cable), or that the iem is fault. I will have to head back to the shop once more today.