Dunlavy SC IV extra tweeter felt?

The heavy wool felt surrounding tweeters and mids on John Dunlavy's speakers were intended to reduce refections and improve imaging. That was never attached to the drivers themselves.

So if the OP's tweeters have any felt attached to the domes then as Zd542 suggested, it was likely done on replacement tweeters rather than original. Four felt pads, even if very small, seem likely to damp/reduce HF response by a significant amount.

"So if the OP's tweeters have any felt attached to the domes then as Zd542 suggested, it was likely done on replacement tweeters rather than original. Four felt pads, even if very small, seem likely to damp/reduce HF response by a significant amount.
Pryso (Threads | Answers | This Thread)"

Yes. That was exactly my point. When I looked at some pics of the OP's speakers, I couldn't find any that had diamond shape felt anywhere near the tweeters. Not to be confused with the wool perimeter for reducing reflections. They were all in place. Since the company is no longer in business, I thought the diamond felt pieces were used to mod a tweeter that wasn't exactly the same.

You have some of the best designed speakers ever produced. I have a pair of the SC-IVs as the front speakers in our reference HT room with an SC-I for the center channel and a set of SC-IIIs for the back corners. Then using two ceiling mount Thiels for the last two channels. Running double SVS subs mounted on Mapleshade bases spiked to the floor to round out the system.

I have found that Dunlavy speakers do more things well than any other speaker line, short of spending 20K or more. Any tweak in the chain is immediately apparent. My guess is similar to what has already been expressed about the felt treatment. If you want to experiment a bit with the sound you might want to try some of the Marigo Dots. I have used these with a couple of applications to adapt the sound to the room acoustics.

I had sc III's and the felt was present on my speakers as well.

The felt help remove peaks in response that can happen because of cabinet design... We were doing this in the late 70's... Felt can make a serious improvement in cutting defraction... depends on the drive and cabinet.