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info wanted re B139, B110 and dn12

 
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harry h
Junior Contributor 20+


Joined: 15 Oct 2004
Posts: 24
Location: Kapiti coast. New Zealand

PostPosted: Wed Dec 29, 2004 7:59 am    Post subject: info wanted re B139, B110 and dn12 Reply with quote

Hi all. I am studying the science of crossover design and am practising by trying to design a crossover for the B139-110 and T27 combo and then comparing it to the Dn12. However the specs I have on these units gives sensitivity figures for the 139 and 110 as volts required for 96db output and the T27 in the more normal db/watt/metre.
I have tried converting these figures back using the principle of 2.83v= 1 watt into 8 ohms but the results dont seem to tally, so can anyone tell me the figures for the 139 and 110 at 1 watt/m.

The other thing I was wondering was why does rhe DN12 cross over at 3500hz which is the top of the 110s freq range yet the T27 freq range starts at 1000hz. Is there any reason why the crossover point isn't closer to the 2250hz mark.

Hopefully someone can alleviate my confusion.

Cheers
Harry
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ColinR
Über Contributor 1000+


Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Wed Dec 29, 2004 6:59 pm    Post subject: Reply with quote

A few numbers to keep you happy Harry Very Happy, before you are upset by the follow up Twisted Evil .

DRIVER.................KEF Spec.....-..... Measured both @ 1W/m

T27A-1032................84............-............... 85
B110-1003................85............-................88
B110-1057................84............-................87
B139-B-1044............. 84............-...............89
B200-A-1014............ 85............-...............87
B200-G-1075.............87............-...............89
B300-B-1071............. 87............-...............89

The woofers tend to loosen up after a bit of use you see.

The B110 has a nasty resonance at 4Khz and a hump at 2kHZ - the nasal honk so much lover by LS3/5a users.

The natural the frequency roll-offs' of the B110 and T27 fit each other quite well btw.


Very Happy HAPPY NEW YEAR Very Happy
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harry h
Junior Contributor 20+


Joined: 15 Oct 2004
Posts: 24
Location: Kapiti coast. New Zealand

PostPosted: Wed Dec 29, 2004 7:42 pm    Post subject: Reply with quote

Cheers for that Colin, confusion sorted. Very Happy
And happy new year to you too.
cheers
harry Cool Cool
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