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hogeye56
12-20-2007, 05:23 PM
I own two pairs of 4412A monitors. Power will be supplied by a Crown XTI1000 power amp, 275@8ohms and 500@4ohms, per channel stereo.
What is the best way to hook up both pair? Would a second amp be the best way to go or will piggy-backing off of the dual banana be OK? Of course I would prefer not having to purchase a second Crown.
This the first time I have tried a set-up like this and I plead ignorance and will defer to the experts.

Thanks,

Clyde W.

SEAWOLF97
12-20-2007, 05:58 PM
as I understand ....2 eight ohm sets will present a 4 ohm load (8*8/8+8 ??)
so check and see how you amp is rated with a 4 ohm (or sometimes lower) load.

I had the same issue, but mine were 4 and 8, giving a load of 2 ohm, so I went with seperate amp for A's and for B's. My preamp will control 2 amps so it all worked out fine.

Hope this helps, corrections surely to come if I'm wrong...:o:

grumpy
12-20-2007, 07:43 PM
That amp is rated to operate down to 2 ohms in 2 ch mode.
You might prefer the sound of two amps, but running two pair of 4412
shouldn't harm the amp. If you don't have a manual ... go get one at
www.crownaudio.com :) -grumpy

Zilch
12-20-2007, 08:15 PM
http://www.jblpro.com/pub/technote/fat_wht.pdf

Like this?

BMWCCA
12-20-2007, 10:00 PM
I'm not all that familiar with interpreting the graphs but stacking them doesn't really seem to improve any characteristics other than sound level. And what's happening at the high end with the weird wave form? Are the two tweets messing each other up? Would the 052Ti be any different? What would happen if you disconnect one 035ti?

Zilch
12-21-2007, 12:15 AM
See #2 Demonstration of Principle in the tech note:



When two sound sources producing identical program are displaced relative to each other, they will combine to produce a unique interference pattern that depends on the observer's location. The interference pattern is a result of the different arrival times from the two sources.


It's messed up from 500 Hz on up, actually, more severely above 1 kHz.


Compare the red curve to the black one. Red is one playing, black is both.


I reversed the phase for the blue curve to highlight where the trouble is.


I am showing worst case orientation, measured on-axis with the lower tweeter, as I recall.


I invite anyone with a pair of speakers and measurement instrumentation to replicate the experiment and post their results here.


Move the mic around and watch what happens on an RTA, for example.


Are the two tweets messing each other up? Would the 052Ti be any different? What would happen if you disconnect one 035ti?They're all messing with each other. The only thing you can leave running is the two woofs, and you'd have to put a lowpass filter on one of them, at what frequency may be calculated from the wavelengths and the distance between them. See the illustrations in the tech note....

hogeye56
12-21-2007, 05:26 AM
Zilch,
I am placing them in the corners of a large room, about 40X40. They will be placed about 7 feet off the floor. I am currently running one pair of 4412A's on the Crown. I am working off of the theory of if one pair sounds as good as they do, two pair will be mind blowing. My theories often do not work out in practice.
If I do wind up with another amp, will it have to bridged mono? How "careful" will I have to be about overpowering my precious JBL's?
As you can tell, my learning curve is vertical.

Clyde W.

pos
12-21-2007, 05:36 AM
why not find one more and run a 5.1 setting instead?

Zilch
12-21-2007, 12:03 PM
I am currently running one pair of 4412A's on the Crown. I am working off of the theory of if one pair sounds as good as they do, two pair will be mind blowing. My theories often do not work out in practice.This is an excellent theory if you listen with your gonads and not your ears.

It's axiomatic: Multiple sources playing the same program material in the same space will interfere with each other.

Getting it right is called "Steering," as described in the tech note.

As you please, of course. I'm just telling (and showing) you what I know.

This is NOT new territory.... :blink:

grumpy
12-21-2007, 04:56 PM
This is an excellent theory if you listen with your gonads and not your ears.
:rotfl::rotfl::rotfl:

http://www.youtube.com/watch?v=ph8kGPXOoUw

Sing it, Udo!

put 'em in the corners. turn it up! you might excite some boomy room modes,
but it should be fun. The comb filtering Zilch has shown is for stacking
(which has been both a popular and unpopular topic of discussion).

-grumpy

Robh3606
12-21-2007, 07:30 PM
This is an excellent theory if you listen with your gonads and not your ears.

Come on!! There has got ot be at least one time you just cranked it all just for the hell of it. Sometimes it fun to just let it rip.

Rob:rockon2:

Zilch
12-21-2007, 07:54 PM
Come on!! There has got ot be at least one time you just cranked it all just for the hell of it. Sometimes it fun to just let it rip.
I've got 'em too, y'know, but also, well, ... "finesse." :p


:rockon1:

Robh3606
12-21-2007, 08:09 PM
OH that's cheating

Rob:applaud:

Zilch
12-21-2007, 10:40 PM
It pisses me off they're not mirror-imaged. I have a thrashed pair I may deconstruct to see if the baffle can easily be reversed. :dont-know