When this thread was begun, I was convinced that that the D220Ti was obviously superior to the D210Ti driver. Its factory measured impedance curve was better, and the measured Frequency Response curve was also flatter. The D210Ti's recommended minimum crossover frequency was 2,000 Hz, versus the D220Ti's 1500 Hz. The D220Ti has a phase plug, while the D210Ti doesn't. Simply had to be the better driver. But....
I had both drivers on hand, plus had ordered a pair of Selenium HC23-25 horns to see if Selenium was up to speed on making horns for their drivers. The Selenium horns were a buck or so cheaper then the JBL, and they had some metal horns which might have been better candidates, but cost several times what the JBL waveguides did.
This morning, I tried the Selenium horns on the D220Ti's installed in the EconoWave pair in my shop. Their HF response dropped off at around 10 KHz, and was down by about 8-10 Db at 20 KHz. Not really good, unless you like the Altec Theatre sound. Next, as long as we were removing drivers from horns, etc, why not try the D210Ti's and see how they do. Wow, I was amazed! :headscrat
It appears that the D210Ti is simply a drop in replacement for the D220Ti. No changes to the crossover circuit are necessary. So unless The Zilchster or someone else with more/better instrumentation than mine can come up a reason not to use the D210Ti's I see no reason not to. The choice is yours. Phase Plug or Not! And remember the D210Ti is about $11 each cheaper than the D220Ti. Nice savings.
Since the crossover frequency for the HF was chosen to be 3 KHz, either Selenium driver is well above it's factory recommended crossover point. Scratch one obstacle. Secondly, the impedance curve of the D210Ti is worse than the D220Ti, but it's biggest and highest peak is at 2 KHz, again well below the crossover frequency chosen. There goes another obstacle. The FR of the D210 actually seems to measure better than the D220Ti at the same settings of the crossover. Scratch another one. But does the Phase Plug make a difference? With a D210 on the left channel, and a D220 on the right, I listened to an entire LP which is one of my favorites, Something You Got by Art Farmer and Yusef Lateef. I cannot hear a difference.
The FR's shown are for the D220Ti on top, D210Ti on bottom, mounted on the JBL waveguides left, and the Selenium horn, right. The last pic is the D210Ti installed on the JBL waveguide under test.
Zilch, do you have a pair of D210Ti's to compare?