The sound of Silk vs. Polypropylene vs. Titanium/Aluminum tweeters

One often reads audiophiles preferring soft dome tweeters over metal domes as being a metallic scratchy sound. Is that really so, well here's an interesting article that says it isn't. IMO metal domes seem to sound different but they come with advantages.

http://www.axiomaudio.com/blog/drivers-and-the-myth-of-tweeter-dome-materials/