Active PA X-over for HiFi use

[kyrie48]

I have a PA/Pro 24db active crossover, and it has the LXR connectors... how do you wire it for use with home/hifi [RCA] use?
Or any websites good to explain this process?

TTYL, kyrie

[Iain McNeill]

well, this is the definitive resource
http://www.rane.com/note110.html

but basically, on the input you short the -ve input to ground and apply signal to +ve input. On the output you leave the -ve disconnected and take the signal from the +ve.

...or you can use lots of transfomers

[bver100]

Hi kyrie

The pro kit is using balanced XLR connectors.

What make is the crossover, the reason I ask is that the correct way to get an unbalanced output depends on the circuit used.

For >90% of makes the correct thing to do is to connect XLR pin 1 to pin 3 - this goes to your unbalanced inputs Ground or screen. Pin 2 is the signal and goes to the unbalanced input.

Irrespective of the make the input to the crossover will always be the same. Connect pin 1 to pin 3 for ground and apply the unbalanced output to pin 2.

One thing you should bear in mind is that pro gear is normally operated at somewhat higher signal levels that domestic kit which may mean that it's dynamic range will be compromised if the signal you give it are low - having said that, decent pro gear also tends to much higher dynamic range that domestic (110-120dB not being unusual vs CDs at circa 96dB) so you might still be fine !

when in doubt, drive it as hard as you can (assuming that you arnt overloading it) and turn the level on the amps down.

B

[HK26147]

In a similar scenario I just bought xlr male to rca female adapters.
From MCM ( I think ) they are fairly inexpensive and work fine.

[kyrie48]

Thank you, thank you... now I can dig it out of the closet, and use it after 3+ yrs!!!
I've been using a vintage 12db active, but wanted a 24db to use with a (soon to be built) subwoofer... now I can... very thoughtful for you folks to help... have a good one!!!

TTYL, kyrie

[Iain McNeill]

bver brings up a good point.
some balanced outputs are not true balanced and can be what Douglas Self (in his Audio Power Handbook) calls ground sensing. With these outputs you need to short the -ve line to chassis at the far end. If you leave it floating like I suggested you'll get some wicked hum, as the open circuit ground sense line drives 50/60Hz hum into the output.

A true transformer output will also need shorting at the -ve output, not that there's too many of those these days.

An electrically balanced output, i.e. one with two out of phase driver amps, shouldn't be shorted because you don't know what the shorted driver amp will do (suck amps, blow smoke, generate THD etcetc)

Start floating with the volume down and short as necessary.

[kyrie48]

It's buried in the closet, but the brand is something like McCleelan/d??... bought at MCM.

I'll see if I can check the line outs, or call MCM, or the manufacturer.

Just remembered this thing is a stereo 4-way!! Might use it for a 4-way I recently designed not remembering this. Be a waste to use for sub/midwoofer xover!!

Thanks again,
kyrie

[bver100]

hi iain

[bver100]

hmmm, it seems that i cannot delete or edit posts ....

anyway ...

Hi Iain

the problem with electronically 'balanced' outputs is that the correct thing to do depends on the circuit.

For example with the majority of Rane gear you are correct that connecting the -leg to ground would short that output (although no damage will occur it will strain the op-amp driving that leg). This is because Rane use a simple circuit that puts half the signal on each leg with that on the -leg inverted.

Others like BSS, XTA KT and i think DBX etc tend to use a more complicated circuit that is meant to better emulate a transformer. in the case (as with a real transformer) the correct thing to do is to connect the -leg to ground.

b

[bver100]

having said all that, your advice to kyrie is spot on ...

"Start floating with the volume down and short as necessary"