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Gone to the Dark Side
http://diyaudioprojects.com/Forum/viewtopic.php?f=6&t=6235
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Author:  gofar99 [ 30 May 2018, 21:51 ]
Post subject:  Gone to the Dark Side

Hi Everyone, After spending a lot of time and not a small amount of money on crossover components (I have scads of them now) I decided to bi-amp my Altec Lansing Magnificents. They are the 7 cubic foot (around 200L) cabinets with the improved Altec 15 inch drivers as upgraded by Great Plains Audio (with the alnico magnets) and Radian 475PB horn drivers on SEOS 15 inch wave guides. Awesome components. The crossovers were all large gauge air core, quality poly caps and non-inductive resistors. I tried several arrangements, slopes and crossover frequencies. None really made the speakers sing like I thought they should. So....bi-amping with (gads :eek: ) a Behringer solid state precision crossover. I used a pair of EL84 mini blocks on the Radians and the original EL84/KT88 Oddblocks for the woofers. After much testing with a PC, calibrated mic and most importantly my ears I settled on an 1850 HZ crossover point. The 15s actually are flat (unreal) to just below 4K, the 475s reach to 800HZ. The built in slopes are 24 db / octave symmetrical and I adjusted the levels for top and bottom to match. The speakers were best in phase. Now the speakers sing. The basic issue is that I appear to be extremely sensitive to phase and time delay in speakers. Crossovers are the worst. It is slightly possible that I could use a first order and get by, but the drivers would not be suitable for that. So to soothe my vacuum tube spirit, I pretend that the Behringer has lots of tiny tubes and just listen to the music. :D

Good listening
Bruce
Attachment:
ALTEC.jpg

Author:  Gio [ 30 May 2018, 22:21 ]
Post subject:  Re: Gone to the Dark Side

Hey Bruce, I'm with you. I've been using an Ashly active crossover for a couple years now in a 2-Way open baffle speaker setup. Once you get into the multi-order crossovers and you start using good components a couple of passive crossovers start to get more expensive than an active one. Normal people have to consider the cost of doubling up on amplification. But for guys that have many more amps than we need, bi-amplification is truly a blessing.

If you start to feel like you must have a tube XO, check these guys out: http://www.marchandelec.com/electronic-crossovers.html

Cheers

Author:  Geek [ 31 May 2018, 05:01 ]
Post subject:  Re: Gone to the Dark Side

Heh, once you hear a good bi-amp (ot tri-amp) system, you can never go back for certain systems ;-)

Enjoy!

Author:  gofar99 [ 31 May 2018, 17:50 ]
Post subject:  Re: Gone to the Dark Side

Hi Gio, The cost for sure, the passives were more than the Behringer. I am familiar with Marchand. They make nice stuff. And yes I seem to have no shortage of amps. I no longer know how many there are here.....I would hazard a guess that there are about 25 tube ones and a bunch of various size SS ones. That doesn't cover the receivers I have as well...there are a number of them too.

Good listening
Bruce

Author:  mwhouston [ 11 Jun 2018, 07:48 ]
Post subject:  Re: Gone to the Dark Side

Hey Bruce pull the grill and show us your big driver (lol).

Author:  gofar99 [ 11 Jun 2018, 10:07 ]
Post subject:  Re: Gone to the Dark Side

Hi Mark, unfortunately is was permanently attached by Altec and can not be removed. I do have a photo of it from the rear. It is in place, but none of new bracing has been added at his point. It doesn't look all that big...until you realize the diameter is 30 cm and the box is around 205 liters. The new support stuff is on the sides, front, criss cross and actually holding the rear of the driver in place. Also some non-hardening damping on the SEOs wave guide.

Good listening
Brice
Attachment:
Altec1.jpg

Author:  mwhouston [ 11 Jun 2018, 18:46 ]
Post subject:  Re: Gone to the Dark Side

Thanks.

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