looking for recommendation for high efficiency midrange for open baffle

[hum4god]

Hi

i am starting a new open baffle project and am looking for an open baffle midrange with high efficiency that can cover
500-2000hz . i am considering running them naked AKA no baffle, possibly in a MTM configuration, so two midrange drivers would be used.

candidates i have read about so far are :

Audax PR170MO
great reputation , amazing efficiency , but ridiculous 0.5mm driver exursion (???)

PHL1120
looks good , 96db efficiency, 2mm xmax

B&C 6MD38, 96db , 2mm xmax

18sound 6ND430 92.5db , 2mm xmax

Acoustic Elegance TD6 Dipole 91db , 3mm xmax .

these are all 6.5" drivers as i think that size would suit the OB best , considring 1st dipole peak and the other drivers used.
smaller driver is also possible .

below the midrange i will fill in with two Acoustic Elegance TD15LO which play from 80 to 500hz but could go higher .the low bottom is covered by a boxed sub.
tweeter is Beyma TPL150 , at this time just with the open back , but i plan to either build a dipole horn/waveguide for it, or to purchase one that will shortly be available.

crossovers and correction will be done by a DEQX so high slopes and EQ is not a problem.

any experience and/or comparison and opinion about the mentioned drivers or others that fit the requirement is much appreciated .

Malcolm

[bigfishe]

Try the Tannoy 6.5 out. Covers all the bases

[dewardh]

Go active. Pick any driver you like, for actual performance reasons. Adjust "sensitivity" with the amplifier gain setting.

[Saurav]

I went from the PR170M0 to the 6ND430, both OB, at some point with the same baffle. No regrets. You can definitely push the 6ND lower on a narrow baffle. I too was looking at the PHL and B&C, but then I got a good deal on the 18Sound, so I went with that. I suspect any of these will work well. The B&C and 18Sound have been measured on Zaph's site, and AFAIR both measured pretty well.

[hum4god]

Saurav thanks for the comparison.

dewardh , i am going active . picking the driver i like for performance reasons , well , that is what my thread is about .
i try to find out how the mentioned drivers perform .
efficiency is an important criteria for me and has an influence on performace , but is certainly not the only one.

practical experience with the mentioned drivers or others is what i am looking for.

bigfishe , Tannoy sells drivers ? do you have a link ?
why do you recommend them ?

[bigfishe]

90 db coax good mid bass wonderful highs and can take a beating.
Fr is 55hz to 24hz ,image well you might need to add a tweeter on the rear of the baffle to keep things dipole

[bigfishe]

You can get them used cheap on ebay

[dewardh]

Originally Posted by hum4god

dewardh , i am going active . picking the driver i like for performance reasons

What does "sensitivity" have to do with driver performance in an active system ? ? ?

[hum4god]

thanks bigfishe , but i am not looking for a coax widebander .

high sensitivity has certainly something to do w/ driver performance for me .
if only in the choice of amps i can use,
and also related,
the resulting headroom that you get w/ higher efficiency that is needed for eq on open baffle .
with high efficiency i can use low power class A , or tube amps.
the other drivers i use are highly efficient.

i am still wondering what other people use for hi effi midrange or how the drivers i mentioned compare?

[dewardh]

Originally Posted by hum4god

needed for eq on open baffle

Drivers on OB are almost always limited by excursion, while high excursion and high sensitivity are rarely found in the same driver (almost never with "quality' also thrown in). Not sure what you mean by "headroom" . . . max SPL, max excursion and required amplifier power are all inter-related and everything should be balanced . . . there is no point in having "extra" (headroom) of any one thing, as the system will still be limited elsewhere. What (and how much) are you willing to sacrafice in order to use antique amplifiers?