Coral 25L-25B/Altec 808-8B Speaker

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dubwicht

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Joined 2010
#1
I aquired the above combination for $100 at a shop on the weekend and would like make a two way mono speaker. Will this combination actually work? I have found the design specs for the Coral driver but cannot find the specs for the Altec. I ordered an 811B horn for the driver today.

Has anyone experimented with a horn loading of this woofer? Evidently Coral calls for a 65liter sealed box. However, I assume that a sealed box would not keep up with this driver at 109 db sensitivity. The driver specs are as follows:

12L-25B Paper cone 12" bass driver,
94 dB sensitivity,
lineair upto 3kHz
Re=6.6 Ohm,
Fs=44 Hz,
Qms=11.8,
Qes=0.62,
Qts=0.6,
Mms=40 g,
Cms=0.33 mm/N,
Vas=110 L,
BxL= 10.8 N/A,
L1k=2.6 mH,
60W

Also wondering where to start designing a crossover. I can solder them up from schematics but have never designed one for myself. Does anyone offer a design for pay service?

Cheers, Doug
 
#3
Hello Dave. I was at your DIY festival a few years ago with my wife and had a great time. Just recently got back into building speakers and electronic stuff.

I am working on a three way speaker, a Pete Millett tube preamplifier and this high efficiency speaker for my old preamplifier (just ordered new tubes).

Here are a couple of photos of the Coral driver. Do you require a photo of the Altec driver?

Thanks for the help!
 

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#5
dubwicht said:
........but cannot find the specs for the Altec. I ordered an 811B horn for the driver today.
Click to expand...

The 808-8B is a MI horn driver, so assuming it still has its original diaphragm or proper replacement it plays loud and a bit harsh with a rolled off top end: 808-8B COMPRESSION DRIVER

Replacing it with the 802-8G's diaphragm as used in the Model 19 is de riguer for HIFI/HT. Shelving it enough to mate up to a relatively low efficiency woofer will eat up most of its dynamic headroom though. Regardless, the 811's polar response lines up with a 12" in the ~1350-1500 Hz BW depending on woofer design plus it's high enough to eliminate its horn 'honk'. That, or XO it around 800 Hz and use CD horn EQ.

If the Coral is ~flat to ~3 kHz, then there's nothing to horn load except down low, so would be huge.

GM
 
#10
Talked to Bill at Great Plains and he is going to set me up with a 3127 driver and I will build a 3 cubic foot enclosure. They are almost finished a 1500 crossover that works with this combination and will be finished testing on Friday. Add the 34647 diaphragm and I am all set. Thank you for the help! Cheers, Doug
 
#11
You're welcome!

Interesting, why the 3127? I mean historically the 414 is the 12" choice for HIFI/recording studio apps, especially the earlier AlNiCo versions. For that matter, if buying new, stepping up to the Model 19's VOTT 416 and 1200 Hz XO components is considered by many of the Altec cognoscenti to be the best overall performing they ever offered to the general public.

GM
 
#12
Even with the lower cost driver the single speaker will cost well over $650 and that is stretching my budget. The old Altec drivers sell for close to $400 and that is out of my price range. I wish!

I also like the smaller cabinet used with the 12" driver.
 
#13
Just picked up a 416-8c woofer for a very good price in Canada. All I need now is a crossover and a new diaphram and I am good to go! Do you know if the titanium drivers from Jammin Jersey are any good? Looks like it is Altec all the way after all! Cheers, Doug
 
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