[S Clark]

As you have discovered by now, there are reasons why you don't see many designs using three drivers full range.  However, there are many designs using 4 drivers... two in series connected to another two in series. Mounted very tightly with small drivers, you are basically creating a small line source speaker... and this arrangement solve your impedance problems. Three, all in parallel, is a very real danger to you amp.  You can't trust manufacturer impedance graphs not to be smoothed, hiding problem impedance drops at certain frequencies that would be magnified by parallel hookup.  I'd buy an extra pair of drivers, use only two per speaker, or find another project.

[imassarano]

S Clark,
I figured that, only 4 drivers per speaker with each driver Vas 0.93 cu. ft. becomes a size issue especially the considering bass loading to increase the bass extension, though aperiodic vents may solve it in reducing the volume

[JohnR]

Which driver is it specifically?

[imassarano]

Hi John,

Well, I'm impressed with the Tang Band W5-1880, and would like to give them a try....

[JohnR]

In what configuration were you impressed? Just one?

[imassarano]

Well.... as I have posted , full range so that I don't have to worry about x-overs.

Is that what you are asking?

[JohnR]

No, sorry How many drivers were you listening at the time you were impressed? One?

[imassarano]

O.K. John, I'm with you .

I've not heard them, just heard of them.

I've been messing about with some ideas for speakers and wanted something simple, i.e., full-range or close to, but a bit different from the usual offerings. The down-side of said driver is their very apparent limited output, but otherwise spec well.

[richidoo]

http://www.tb-speaker.com/detail/1230_04/w5-1880.htm

If you use 4 drivers instead of three you can wire two drivers in series, then another two drivers in series, then wire those two pairs together in parallel, which will net an impedance the same as a single driver.  Definitely try a single pair first.

Xmax of 5 mm is pretty good. I think they will be loud enough for you with just one per speaker. Don't count on the frequency response being as flat and smooth as the mfg's plot. Also, you will need a zobel filter to damp the rising impedance in the treble, or some kind of EQ in your electronics. Consider using a current source amplifier with single driver, you'll like it!

http://www.passdiy.com/pdf/cs-amps-speakers.pdf
http://www.current-drive.info/

[JohnR]

I think I read a good report on that driver recently. However at the "new" price, eight is a bit hard to swallow (for me anyway)

[imassarano]

Yes John, they've gone up nearly 50%  , so, looks like 2 per speaker.

richidoo, thanks, that's great info  . Now I'm starting to understand this current source amplifier thing a lot more, and leads me to think about First Watt especially the F4, which should handle 2 drivers in parallel very nicely I think.

I'll tell you what; this forum is GREAT