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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => SR Forum Archives => LAB Lounge FUD Forum Archive => Topic started by: Don Ullstrom on February 22, 2010, 05:44:38 pm

Title: Aux Fed Subs with DriveRack PA
Post by: Don Ullstrom on February 22, 2010, 05:44:38 pm
I am using a DriveRack PA and am only feeding the left side since I am running mono.  I am running a 2 way system crossing at 100hz.  I am thinking about trying aux fed subs and am thinking I can use the right side of the DriveRack to do this.
If I feed the right side from a post-eq aux send, I can connect the right low output of the DRPA to my sub amp right ?  So I would basically be sending over 100 hz out of the left side and under 100 hz from the right side.  I can't think of a reason this won't work, can you ?  Thanx.
Title: Re: Aux Fed Subs with DriveRack PA
Post by: Art Welter on February 22, 2010, 05:52:37 pm
Don Ullstrom wrote on Mon, 22 February 2010 15:44

I am using a DriveRack PA and am only feeding the left side since I am running mono.  I am running a 2 way system crossing at 100hz.  I am thinking about trying aux fed subs and am thinking I can use the right side of the DriveRack to do this.
If I feed the right side from a post-eq aux send, I can connect the right low output of the DRPA to my sub amp right ?  So I would basically be sending over 100 hz out of the left side and under 100 hz from the right side.  I can't think of a reason this won't work, can you ?  Thanx.

Only problem would be if you were hitting threshold on the linked L/R master comp/limiter, bass hits would suck down the mains, snare /Vox hits would suck down the sub.

Been a while since I read the manual, I don’t recall if you can split the L/R limiter.

By the way, 100 HZ is a bit high for an aux fed sub. If your mains can't cut it to at least 80 HZ, you probably don't have the right rig for aux fed subs.

Art Welter
Title: Re: Aux Fed Subs with DriveRack PA
Post by: James Feenstra on February 22, 2010, 06:06:34 pm
if you're crossing a two way system at 100hz you have bigger issues

i doubt your horns can do down that low

either that, or you're actually running three way haha
Title: Re: Aux Fed Subs with DriveRack PA
Post by: Don Ullstrom on February 22, 2010, 06:07:00 pm
Actually I am not using the limiters at all.  I'm crossing at 100hz because that's where the manufacturer of my top cabinets suggests to cross.  I'm using JBL SR4719's for the subs.
Title: Re: Aux Fed Subs with DriveRack PA
Post by: Don Ullstrom on February 22, 2010, 06:09:35 pm
Sorry, I wasn't clear enough.  My top cabinets are passive
and have internal crossovers in them.  So I'm just crossing at 100hz to keep everything under 100hz out of the 15's.  
Title: Re: Aux Fed Subs with DriveRack PA
Post by: Duane Massey on February 22, 2010, 06:45:28 pm
I am currently doing this at my weekend gig, but I don't suggest it. As Art mentioned, the L/R controls are linked and will inter-act. I used a spare analog crossover to limit the bandwidth on the sub input and this has made it useable, but I will eventually either add a 2nd processor or replace the DRPA.
Title: Re: Aux Fed Subs with DriveRack PA
Post by: Jim Duyck on February 22, 2010, 11:09:00 pm
We did this for bi-amped SR4733X's and SR4719X's with no issues.  If you're the one in the driver's seat of the rig, the limiter issue should be okay.  If you're handing the keys over to an eager BE...well...your guess is as good as mine. Surprised
Title: Re: Aux Fed Subs with DriveRack PA
Post by: Joe Brugnoni on February 23, 2010, 11:43:16 am
Don. I am not sure about the DRPA but I know on the 260 they can be seperate,  I might suggest that you go to the DBX site and talk to gadget, He will give you the inside on these.

I know you can shut that function off on the drpa if you trust yourself to operate that way.

Do you happen to have any amps with DSP in them like an XTI?
Title: Re: Aux Fed Subs with DriveRack PA
Post by: Gary Perrett on February 23, 2010, 01:26:22 pm
It is possible to run separate paths through the DRPA, most of the nodules are tied together, but you will have GEQ,s and PEQ's to work with for sure.

You can run a tops/subs and monitor separately, a bi-amp tops and subs, or a fullrange tops AUX fed subs, but the key is the crossover. If you use the high and low outputs on the left channel (for instance)you have only the mid output remaining for the right channel. It is best to stick with even order filter types like 2x4 and 2x6.  You then simply set the desired HPF for the High out  and HPf/LPF for the mid and low outs.
G
Title: Re: Aux Fed Subs with DriveRack PA
Post by: Joe Brugnoni on February 23, 2010, 09:10:51 pm
I forget that you get on here also
Title: Re: Aux Fed Subs with DriveRack PA
Post by: Gary Perrett on February 23, 2010, 11:36:04 pm
 Very Happy Hi Joe Very Happy yes, I frequent here and listen and read...... been here a LONG time actually...contribute when I have something to offer.
Don has crossed over..hoping he gets what he is looking for.
Be well
G
Title: Re: Aux Fed Subs with DriveRack PA
Post by: Joe Brugnoni on February 24, 2010, 09:54:59 am
Thanks Gary, your the best and I sure appreciate all the help you have given me!!