soft dome versus hard dome tweeters

@erik_squires 

Thanks for the WAWB reference. I looked that up on DIYaudio. One guy talks about the excellent balance and sharp percussion. This is what I'm noticing on my system lately. With  my CD horn it wasn't really doing those things to full capacity until I recently just EQ'd the heck out of it using an FIR filter. The raw response droops considerably at both ends, but I was afraid to "overdo" the EQ. Now it's flat as a board all the way down to the 600Hz LR 48 dB crossover point, and it follows the crossover target with near perfection. And, the phase is flat all the way through. That much EQ required as much as -15 dB from the peak at around 2 kHz. It seemed too extreme to me, but it was the right thing to do. 

Speaking to the beaming on top with the WAWB, I've been toying with a Dayton aluminum dome midrange, which has a breakup peak at about 12 kHz. That thing beams on top too, and I think I understand why hard domes beam like that. The middle of the dome is just too loud compared to the edges, and the middle part of the dome is relatively flat. The sound off the dome at all points radiates perpendicular to the surface to make spherical waves, but with the center being too loud, the pattern doesn't look nearly as good as one would hope. I think one solution might be to somehow reduce the efficiency of the dome at the center. A way to do that might be to make it leaky in the middle by drilling holes. This will reduce the overall efficiency as well, but it might be worth it if it improves the dispersion. The 2" dome could be putting out something up to over 16 kHz with half way decent dispersion if the hole drilling works. And of course the resonance would need to be notched down.

I bought an old Dremel drill press from my neighbor. I'm ready to drill, but wondering if it's worth it. It might do something really bad and render the driver useless. If it works as well as I'd hope, it'll reach down to 600Hz without horn loading. Maybe 400Hz with horn loading. That's just a little lower than I'm already getting with my JBL 2426H on its horn.

@asctim DIYaudio is the best place to discuss mods to drivers, but I suggest you want a phase plug instead.  :)

Both metal and soft dome tweeters have improved over the years. But loudspeaker design, possibly more than any other aspect of hi fi, is about system performance. As an example, the Focal inverted dome titanium tweeter sounds radically different in Focal and Wilson speakers (of the relevant era), respectively.

I had speakers with metal drivers for years, seemingly more info than previous soft domes although varied in ringing, glare or sibilant extension.

Even some soft domes were overbearing.

Then I went with Dali Menuet SEs which comparatively subdued but also took out alot of the nuances in music I listened too and I found them way too refined.

Dali Opticon 1s were much better only giving up some resolution and note weight but still decently controlled glare and sibilance, comparatively speaking.

Now have Audel Magika II using a Sartori SB Acoustics tweeter and while it is very revealing, it lacks the glare and controls sibilance better, so it replaced my metal options.  I still have one set of speakers with metal domes, a budget speaker whose attributes are so good overall, I don;t want to sell.  Very melodic on some material, euphonic in spite of the sometimes glare.  Less resolution but plays well with ANY amp, source or genre.  Not neutral, V shaped and good for low level listening.  The titanium tweeter and treated paper woofer work well together.

My other speakers measure better, perform better in the audiophile sense but there it is. 

Also had Martin Logan 15i which were really good with soundtracks re resolution and voice naturalness but didn't like it for music.  I thought it had more to do with the Aluminum woofer than the AMT.  Also, it didn't give nuances like spatial effects like the Dali when I compared but I preferred the 15i with voice in soundtracks.  All else the Dali I thought were better.

If I were to upgrade from here, at higher prices I think I would target something with a good soft dome considering paper variant woofers, even though I am happy with polypropylene as well and avoiding metal infused woofers.  

My last few speakers , Heresy III , Forte IV , Revel M106 , PSB M2, and a few others had metal domes. They all sounded pretty good.

I had a pair of Sonus Faber Concerto that had a silk dome, Igave them to my brother. I replaced them with a single driver "full range" speaker and I missed the sparkle of a conventional 2 or 3 way..

I recently bought a pair of Studio Electric M4, an acoustic suspension compact monitor. They use a 6.5" High excursion mid/woofer and a 1" silk dome tweeter. They sound phenomenal. In terms of sound quality I think they may the best sounding speaker I have ever owned. I can listen for long periods without fatigue, i credit the tweeter for that. . Awesome speaker.