Single amp for tops and subs

[rec]

I would like to know how to set up my system using one amp for my smaller gigs
I have 2 t30's and 2 OT12's
DRPA+
QSC GX5 amp
The subs are easy since I am running mono, one cable out of the DRPA goes to one of the channel inputs.
I am not sure what to do with the tops though
I have two cables coming out of my DRPA for the tops but obviously only one input on the amp since the
other side is for the subs.
I have never tried this so am a little nervous about expermenting

[SeisTres]

I would like to know how to set up my system using one amp for my smaller gigs
I have 2 t30's and 2 OT12's
DRPA+
QSC GX5 amp
The subs are easy since I am running mono, one cable out of the DRPA goes to one of the channel inputs.
I am not sure what to do with the tops though
I have two cables coming out of my DRPA for the tops but obviously only one input on the amp since the
other side is for the subs.
I have never tried this so am a little nervous about expermenting

If the DRPA+ can combine both of the inputs (L and R), then just tell to send the combined output from one chanel (Left high output). It usually sums the L/R for the subs but I don't know if you can do it for the tops. However, if it can no do that, get a mixer (or something that you sum the L/R, just be sure it's not just a "Y" cable that has two inputs and one outputs, it must be able to mix signals), then simply connect the L/R on the main output, and send the combined signal (mono) to the DRPA+. Now just run a speaker cable to the subs from the "sub" channel (as I assumme you were doing) and parallel them, then run a cable to each of the otops from same "top" channel, like this, the cable lengths will be the same for each otop.

[bzb]

On the Crown XTi, there's an option for it to be summed CH1 + CH2, which has a +6 dB boost. There are many mixers that do this, as well, usually output only through the Left channel, as Seis mentioned.

There's probably a way to do this in the DRPA.

[rec]

Cool, let me look into that and see what I find out
thanks

[Ron K]

On the Crown XTi, there's an option for it to be summed CH1 + CH2, which has a +6 dB boost. There are many mixers that do this, as well, usually output only through the Left channel, as Seis mentioned.

There's probably a way to do this in the DRPA.

Every mixer will do this if you put the same signal into two channels!
With a standard mixer you simply use just the L or R output to the amp and Pan the L/R on each strip to the output side you are using.

If using a DJ mixer most of them have a Mono /Stereo switch....put it in mono and use either side out.

With the DRPA I dont believe you can mono couple more then 1 set of outputs a time in any of the 5 configurations available inside that unit!

Your best bet is to sum the signal before the crossover if you can using another mixer or sell the GX5 and DRPA and Get a Crown-xti.

[SeisTres]

Finally found the site i had seen for this.
http://www.tkk.fi/Misc/Electronics/circ ... nesum.html

However, this has to be line level(+4db) since if anything lower will be attenuated so much, the level will become unusable, not to mention the high frequency roll off. I read another site that if you're going to use phono level (-10db, not sure about the name though), that 2kohm should be used. I have only tried the one with 10kohm but did find many uses for it since I used rca jacks and mostly everything rca is -10db However, on my next order for partsexpress i'll be trying lower resistor values. but hell, they're so cheap, you could try them out without even soldering anything and only spend a couple of dollars.

OR, just get this http://pro-audio.musiciansfriend.com/pr ... sku=621108

or a real mixer like ron described.

EDIT: ok, I tested out different resistances in the circuit and 2k seems to be about right for -10db. While it still looses some voltage, it is quite usable, as opposed to the 10k resistor which the -10db can not handle. Other than the voltage drop, other detrimental effects are unnoticeable.

So you might want to give it try, you can buy all the stuff from radio shack.

Oh, and I wouldn't do more than one left and one right channel on that circuit, any more channels and it would be better to use a switch to change between the sets of two-channel-minimixers.