four inch driver with good efficiency and low Rms/high Qms?

[twest820]

Looking for a small driver similar to the SB12NRX but with an efficiency of 90dB SPL 1W/m or better versus the SB12's ~84dB. And pulling a total blank, though I've found a couple nice five inchers and several sixes. Any suggestions? Application is the mid in a four way nude dipole, target frequency range is 500Hz to 2kHz---I've been planning to use the BG Neo8 but the fairly good front/back wave symmetry John K is getting out of the 10F in the Nao Note has prompted me to check for other options.

[GOWA]

I'm not sure if this meets your criteria but Zaph just tested the Scan Speak Discovery 10F/4424G00 and it looks quite nice.

[bjorno]

Agree with GOWA, Try use the HR program when comparing the drivers:

b

[twest820]

Since John K was using it the 10F was one of the first drivers I checked. However the sensitivity of both variants is a bit under 86.5dB 1W/m. Agree the 8424G00's a stronger candidate than the SB12 based on sensitivity and Rms, but the 10F's unusually low Sd is a bit of a problem---this is visible in bjorno's HR comparison above 150Hz. I agree with Zaph the 10F's more of a three inch driver.

Looking over ScanSpeak's lineup again I suppose I should add the 15M/4624G00 to the list of fivers.

[ScottG]

Fostex has a few, 126E and 127E,

ALTEC CF208-8A,

3" driver:

Faital Pro 3FE20.

I'm betting all have some problems with their surrounds, at least when compared to the Scan 10F.

I can vouch for the *sound* of the Altec driver (..but I haven't had access to measurement equipment for some time now). The build quality *looks* fairly decent as well. Again though, I can almost guarantee that it has some issues with the surround.

I'd bet that the Faital Pro's sound is the *least* likely to have problems with it's surround of the grouping, AND I'd bet the subjective impression is *very* detailed - more so that even the Scan 10F.

[twest820]

The FE126E and FE127E are discontinued, replaced by the FE126En which has 0.35mm xmax. The FF125K is probably a stronger option, particularly as it lacks the FE whizzer but, like 0.35mm, its 0.15mm xmax is certainly painful for dipole use. Not having any luck digging up the Altec, but the Faital Pro 5FE120 is probably the best set of tradeoffs so far. Thanks. (If I can figure out how to get my hands on one, anyway. )

Originally Posted by ScottG

I'm betting all have some problems with their surrounds, at least when compared to the Scan 10F.

Yup; the motor, too. Just looking for something with good dynamics and where a small amp actually has enough power to drive the thing. I'll cross to the woofer in the four way before the mid ends up needing too much excursion, but it does need enough xmax to hit 0.5mm or so with good THD/IMD.

[planet10]

Originally Posted by twest820

The FE126E and FE127E are discontinued, replaced by the FE126En which has 0.35mm xmax. The FF125K is probably a stronger option, particularly as it lacks the FE whizzer but, like 0.35mm, its 0.15mm xmax is certainly painful for dipole use.

If you don't have a need for a whack of them i have FE127 & FE126. Inuendo from a German distrib (who heard it from the factory) is that the xMax is the same on the FE126En as on the FE126e, but was incorrectly stated in the earlier driver.

FF125 is also discontinued. Rumour (from a different distrib) is that we could see a variation on the FF line but with specs closer to the FExx7 series than the FExx6 series. That doesn't help your project thou.

dave

[thomasjefferson]

Originally Posted by ScottG

I'd bet that the Faital Pro's sound is the *least* likely to have problems with it's surround of the grouping, AND I'd bet the subjective impression is *very* detailed - more so that even the Scan 10F.

This driver does look promising, a very compact dedicated midrange with nice sensitivity and a nice price. I found a vendor with a quick search asking US$25 for these. Kind of a goofy mounting flange though, it suggests reverse-mounting for sure.

[ScottG]

Originally Posted by twest820

Not having any luck digging up the Altec..

I got the part number wrong on the Altec..

ALTEC CF404-8A Speakers

http://www.altecpro.com/pdfs/CF404_SS.PDF

Again, sounds pretty good - but probably measures pretty poor. (..I'd purchased it for a radial mid use, and it's pretty good for that.)

[twest820]

Originally Posted by planet10

If you don't have a need for a whack of them i have FE127 & FE126.

Thanks for offering. So far the 5FE120's still in the lead.

Originally Posted by ScottG

ALTEC CF404-8A Speakers

Lack of T/S parameters in the datasheet's usually a warning sign. For the price I'd expect decent but unexceptional with the trafo bypassed.