GREQ: can you take a picture of the front side of those 2 headphones from the baffle/ear side views please when you feel like it.
I am curious . Also do they have a whitish cover over the driver on that side also? - YES (it's some sort of metal mesh)
And thanks for taking the time to post pics and your experiments so far with them.
I forget if you ever found out what the impedances are for the drivers? - No, I just don't have the technology
And is the other one also strange with the offset holes when you look through them? - Yes and No (Universum is only half as 'incorrectly' aligned as the Watson)
Here is the front views of the grills.
Universum has 4 half circular grills (only the top half is vented) and the square silver grill is also a vent.
Watson has a single row of vents (they look white here as I was experimenting with cotton wool at the time of the photo).
This is one of those SFI drivers that was being sold on ebay as 'tweeters' or whatever it was they called it. (A few of you guys here got a hold of some of these too) I experimented with them by installing them into the universum just to see what they sound like.
As you can see, the holes are PERFECTLY aligned. (This side has a thin layer of 'felt', the other has a thin plastic fabric).
The metal 'housing' is slightly smaller than the plastic housing around the ones found in both headphones.
These are the Universum drivers, which are about half as 'badly' aligned as the Watson's.
Here you can see the insides of both phones side by side, including stock damping, lying beside each.
The drivers have a fine wire mesh on either side of the driver, unlike the 'ebay' one which has a thin plastic fabric on one side and thin felt on the other.
MODDING the Watson's damping solution:
Having two near identical headphones made it very easy to A-B test various damping solutions and simple mods.
I experimented with sealing the vents, adding various amounts of cotton wool and foam.
Closing holes didn't add anything to the sound. At most, it improved the sub-bass volume and impact, but the mids always suffered, and the high mids were not smooth any more. The resulting 'closed sound' was also quite bad.
After a while (after trying various music genres) I discovered that the Universum (left) with yellow wooly stuff and thin foam actually had a more neutral, natural (timbre) and open sound. So my quest for today was to bring the Watson as close to it as possible.
The stock Watson's stock foam damping I found to 'close' the sound somewhat. I initially put in a full piece of cotton wool which beefed the bass up quite a lot, but high trebles weren't as liquid as the other.
I halved the cotton wool twice before I was happy with the high-mid/treble smoothness and tone, but the bass shrunk each time I did so. So I dug out some old cheap packaging foam I had lying around. It is easily less than 1/3rd the density of the origial stock foam but about the same thickness, so I added it behind the cotton wool, much like the Universum damping strategy. To my delight, they now sound almost the same, with the exception of the Watson having a little more bass, which to my ears sounds a little more balanced. This is probably because the packaging foam is 5X thicker than the Universums 'foam sheet'.
Interestingly I did try various mods and materials on the Universum, but everything I did made the sound worse. So whoever at Universum came up with the venting and damping on this, probably knew what they were doing and had good ears too!
So, the 'ebay' drivers inside a headphone:
I think these suffer a lot from the felt cover at the back of the driver. The treble is a bit woolier and the sound is more closed than the others.
I didn't really want to experiment with taking off the felt and exposing the driver. I'm not quite brave enough for that yet.
However the overall sound signature is practically the same.
Even the difference between the alignment of the driver holes doesn't seem to have any significant affect on the overall sound.
I didn't spend too long trying to figure this out, but that was my impression.