Best 6.5” 95+ dB mid: ‘Audax’ PR170M0 v overlooked Italian?

[rick57]

The (was Audax) now AAC PR170M0 is the most widely liked high dB mid cone.

Just learnt though that IMO smart & thorough Earl Geddes in this range uses a B&C driver, the similarly priced 95 dB 6MD38 www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=294-651. At Audio Asylum several B&C are very well reviewed, though nothing on the 6MD38.

Technical features:
- The B&C cone has an elliptical profile. I think the benefits are meant to include better controlled break up modes, reduced directivity & better transients(?). What profile is the PR170M0?

- the Audax has 0.5 mm Xmax, the B&C 2 mm: the Audax is probably intended to be used about 1 octave higher.

- the B&C is treated with a stiffening finish (smoother), not a big deal (can DIY); but the PR170M0?

Unibox calc of dB @ 2.83 V is identical for both: 94.4 dB.
Being mids it’s not that useful, but the PR170M0 specs 100 dB, and the B&C 96 dB, so is the Audax extra 4 dB, just more cone breakup?

Any advice welcome

Thanks

 

[rick57]

Off-axis behavior

I’ve known that Earl Geddes (along with Linkwitz) places much emphasis on off-axis behavior.

I’ve just learnt that he used to consult to B&C . . quite likely the 6MD38 has good off-axis response . .

Anyone comment on the off-axis response of the PR170M0?

Thanks