Originally Posted by Breau
In my opinion 1.4 is the way to go. Many more available and in use around the world and more choices of makers. More options is always a good thing. 1.4 has the speed of the 1 inch and the low frequency extension of the 2inch.
22 or 24 would be great with low frequency to at least 650hz... with more vertical dispersion. 50-70 degree vertical dispersion to go with that beautiful horizontal dispersion is a must for my studio monitor and home monitor design.
I always assume that anyone spending as much time and effort on a sound system as people do here... would spend the time and effort to maximize their room acoustics. Great sound depends on a great sound system AND a great room. More vertical dispersion would help with stereo imaging and soundstage as well as a bigger sweet spot for group listening in a home or studio.
Congratulations on all of your effort. You have hit a home run. Now be like Babe Ruth and hit another one.
I agree that the 1.4/1.5" route is a good route for 2-ways with some of the modern materials used. The best materials are coated Titanium and Beryllium. Beryllium is absurdly expensive. JBL won't sell their Be drivers individually and TAD TD-4003 is $3k. You can buy aftermarket Be phragms for JBL CDs but they are around $400-500ea.
That leaves the treated Ti drivers and I only know of two available. The aquaplas'd 4" 2452 JBLs and the 18Sound NSD1480N and NSD1460N. The JBL's retail for about $1200 but can be found on ebay for less and the diaphragms are not that expensive. The NSD1480N is $500 and I don't have a price for the 1460N. That isn't bad for a medium format driver with a coated diaphragm.
The JBL's advantage is that it is a 4" VC which means it should play lower. The 18Sound's advantage is price, availability and potentially a more advanced coating (just a guess based on their paper).
Of course there are cheaper 1.4/1.5" CDs that are either Ti or Al, but IMO you are probably better off going with a poly or treated Ti 1" throat SEOS-18 if you want a low xover point. Or go with a three-way using a mid horn.
Presently, the best 1.4" horn option is the 18Sound XT1464. It is a well-regarded horn but on the small side at just 15" wide thus it only holds pattern down to ~1200hz. IMO, there would definitely be a place for a larger SEOS built around the NSD1480N. Maybe a SEOS-24. In a home or studio setting, the NSD1480N should play easily down to 600-700hz.
I guess what I'm saying is that after thinking about it for a bit, a 1.4" throat would be better than a 1.5" throat. I really like my JBL 2452H-SLs, but I think the market would be bigger if built specifically for the NSD1480N instead. I know the 18sound driver will be easier to obtain in Europe and is available in the US.
A $500 CD combined with a $300 horn (wild guess on price) is a far cry from the 1" versions, but should be a pretty amazing performer for those with more space and money.
Breau, as far as directivity, the SEOS models all measure around a nominal 60deg vertical and 90deg horizontal. I agree this is optimal for most situations. By my math, a SEOS-24 should hold pattern in both the vertical and horizontal while providing a nice wide lobe for very smooth directivity and off-axis response.