Need a crossover for my new 400 lb center channel speaker...

**analog addict** · July 25th, 2012, 11:47 AM

Since this is an old style cabinet, I'm more or less going to have to use these to load it....

The plan is to plunk my 3rd 1005b on top and load it with a 288, prolly a 288b. I'm not going to woory about the extreme highs and lows given the intended purpose.

Anyone know whether or not there is a standard crossover for these units?

**valhallax** · July 25th, 2012, 09:28 PM

i think its closer to 475 lbs..ask me how i know? 515a's!! very nice, ive heard these are the absolute best for voice, that being said they might need a different crossover than the 515b's. phenolic spiders..pure altec porn there! most were using the 500c crossovers

**cradeldorf** · July 25th, 2012, 11:56 PM

I hope you have a big theater for that monster.

**analog addict** · July 26th, 2012, 12:59 AM

Originally Posted by cradeldorf

I hope you have a big theater for that monster.

I wish it was bigger. 45' by about 30' by 10' high is my current listening space.

These are the right and left channel set ups on the 45' wall.

**gortnipper** · July 26th, 2012, 06:03 AM

Wow, that is sick!

**bowtie427ss** · July 26th, 2012, 07:01 AM

Originally Posted by gortnipper

Wow, that is sick!

I really think he needs a couple rows of par 64's across the ceiling in front of them, and maybe a couple pinspots in the back of the room focused just wide enough to illuminate the speakers themselves. Oh, and about 200 running feet of black backdrop to cover all the pink without undoing it's acoustic goodness. I'm afraid if AA sheetrocks that space, he won't like what it does to the acoustics of it.

**voice of the theater** · July 26th, 2012, 08:22 AM

Wow, now THAT is a great STACK of Altecs!!

**Altec Best** · August 6th, 2012, 12:53 PM

Wish I lived closer ! Sounds like you guys had a great time !

**Panomaniac** · August 6th, 2012, 09:11 PM

OK, here are some pretty graphs. You'll see the 288 on 1005 impedance curve in green - the dual 515s are in blue.
What would you call their nominal impedance?
impedance center

On the second graph we see the drivers' measured at the listening position after crossover. Green is the combined response. Don't know why the bass looks so bumpy, might have been where the mic was placed. The crossovers ended up being 3rd order at 600Hz for the low pass, 3rd order 750Hz for high pass. Reverse phase.
final center

I'll work on this some to come up with the values for a passive crossover given the impedance curves. Will post results here.

EDIT: Images updated for better size

**aditya** · August 7th, 2012, 12:40 AM

Many thanks "Panomaniac" for the graphs. I am yet to see a thread on 210s with real graphs. This will be very useful for ref. sake.

From the impedance graphs it seems the dual 515s (assuming they are in the parallel mode) are really 20-24 ohms each (@ 1 K Hz.), as specified. It is surprising that the DC values are at 9 ohms, as measured by 'AA'. Or may be he also had measured the value in the parallel mode, and while the actual value was at 8 ohms (which also is confirmed by the posted graphs), the extra 1 ohm was the meter leads error.