Hi-efficiency 8” mid for 160hz to 1300hz…

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youknowyou

youknowyou

Member
Joined 2014
Hey everyone

i plan to use dual Beyma 12br70 per side ala Amphion Krypton woofer arrangement ( woofers mounted on the each side panels)

dual 12br70 is about 99db/98db. I therefore need a mid of about 97db/96db

xo first order 160hz/1300hz, so smooth roll off for the mid is critical

many thanks
 
Y

YSDR

Member
Joined 2013
Here is a possible candidate, the 18 Sound 8NMB420:
https://www.dibirama.it/home-page/m...nd-8nmb420-8-mid-woofer-8-8-ohm-400-wmax.html

Or with sligthly lower sensitivity, the 8MB500, :
https://www.dibirama.it/home-page/m...und-8mb500-8-mid-woofer-8-8-ohm-400-wmax.html

I think the problem with the B&C 8PE21 for the OP's task is the very low Qts that causes early rolloff on the low-end, it already have about -8dB at 150Hz, at least according to the factory datasheet. But it was not mentioned that only the filter is 1st order at 160Hz or the driver's acoustical response with the filter.
 
youknowyou

youknowyou

Member
Joined 2014
As i will use a first order xo, i dont think i could get away with a xo pointmmuch higher then 250hz if the woofers are placed on the side walls to avoid coloration. Correct?

so i need a mid about 95 db with smooth top end roll off, very fast response to match the dual woofers and planar tweeter xo at 1300hz
 
weltersys

weltersys

Member
Joined 2008
mayhem13 said:
B&C 8PE21 does what you need…..and it’s a fantastic sounding driver to boot. I’ve run them up to 3khz with a simple EQ notch…..best midrange I’ve experienced other than a few very expensive dome mids.
Click to expand...
The B&C 8PE21 response looks really good.
Screen Shot 2024-04-21 at 1.23.49 PM.png

The B&C 8NDL64 and 8MDN51 are slightly less sensitive in the 200-2kHz range, but have more Xmax.
In the 160-1300Hz range, the choice between the 8PE21 and either the 8NDL64 or 8MDN51 might come down to how hard one wants the low mids to hit.
Screen Shot 2024-04-21 at 1.35.22 PM.png

I'm using a pair of the 8NDL64 for subwoofers from 23 to 100 Hz presently, they sound fine up to (and a bit past..) +/-5mm excursion-even when used to 1500Hz.

I would not go higher than 160Hz crossing to side mounted woofers.

Art
 
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M

mayhem13

Member
Joined 2008
Just be mindful as others have pointed out how hard you want the midbass to hit given your desired Xo point…Me…..I like 400-450hz much better for a true midrange driver…….below that, look towards midbass drivers if the volume is gonna be high.

PHL made some great stuff 20 years ago….. not sure about nowadays.
 
weltersys

weltersys

Member
Joined 2008
youknowyou said:
Seems to fit the bill….
https://www.phlaudio.com/fileadmin/user_upload/phl_audio/1426_SpecSheet.pdf
or
https://www.phlaudio.com/fileadmin/user_upload/phl_audio/1752_SpecSheet.pdf
Click to expand...
No frequency response charts to compare (not a good sign..), but the 1426 listing an Xmax of 4mm and Xdamage of 6mm is a bad sign, ~3dB dynamic change might put the driver onto the casualty list.
The 1752 has less excursion (3mm), but a higher Xdamage (9mm), you should hear it distort before it makes nasty sounds.
Xmax.png

The 6.5" drivers can't come close to the peak output of the Beyma 12br70's at 160Hz, but should be within a few dB of what they can do at 35Hz, ~108 dB.
At any rate, youknowyou ('re) music and where it's dynamics lie.
 
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