Members gonzobassman Posted June 11, 2011 Members Share Posted June 11, 2011 I'm currently considering redoing the sub section of my P.A. I have a set of 2-18 subs (Peavey Lo-Riders in JBL designed,local pro-shop built boxes) I am really happy with these boxes,and so are the people who have heard/played through them. I have an amp driving them that on paper says it puts 1680 watts to a 4 ohm load,and I have no doubt that it does.What I am considering is re-wireing the boxes where one speaker is +1/-1,and one speaker is +2/-2 doing away with the large (and rather weighty)amp,and going with 2 QSC GX-7s. I will effectively be running 700 watts into each 800 watt driver. Smaller shows=1 sub. Larger show=2 subs.Larger than that hire out. Since I run all QSC in my FOH,and monitor rig,do you guys think that this is a decent idea? Not really so much an upgrade as just keeping the amps all the same,but offering more control on the bottom end. Keep in mind that 2 GX-7s will still weigh about half of the existing amp a GRF 8950. I know its a no-name but I got a great deal on it from a very trusted,and respected friend,and it has never let me down.Even on outdoor (festival) type shows I can put the kick right where it goes. Thanx in advance,as always for any input. Link to comment Share on other sites More sharing options...
Members monkeyland Posted June 11, 2011 Members Share Posted June 11, 2011 I would assume you would be using the two extra gx7 channels for the tops. If so that is how I run my rig except with gx5s. In my case I still run a separate crossover as opposed to the one in the amps since it gives me more control and contains the Hpf that I need. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted June 11, 2011 Members Share Posted June 11, 2011 Unless the two drivers are in separate compartments (?) you run the risk of destroying one if one channel cuts out for whatever reason. I'd just switch to bridged RMX1450's myself - actually that's what I have run in the past . Link to comment Share on other sites More sharing options...
Members RoadRanger Posted June 11, 2011 Members Share Posted June 11, 2011 I would assume you would be using the two extra gx7 channels for the tops.I'm pretty sure he's talking about driving a pair of 2x18's with one driver per channel so would use up all four channels on the subs. Link to comment Share on other sites More sharing options...
Members monkeyland Posted June 11, 2011 Members Share Posted June 11, 2011 Right. Missed the 218 part Link to comment Share on other sites More sharing options...
Members gonzobassman Posted June 11, 2011 Author Members Share Posted June 11, 2011 Yea,I was thinking one side per driver. They share a common center port,but I guess that means they are not in seperate compartments. I could also go with seperate single 18 boxes,but I lack the credentials to truly do justice in the box building dept.! Lol Link to comment Share on other sites More sharing options...
Members gonzobassman Posted June 11, 2011 Author Members Share Posted June 11, 2011 I would assume you would be using the two extra gx7 channels for the tops. If so that is how I run my rig except with gx5s. In my case I still run a separate crossover as opposed to the one in the amps since it gives me more control and contains the Hpf that I need. I currently run a GX-5 on the tops as well w/an external crossover. I have also used the GX-5s internal crossover with lower powered single 18 boxes I have (2 per amp side) and Club V tops (2 on the other side) with excellent results. Link to comment Share on other sites More sharing options...
Members Unalaska Posted June 12, 2011 Members Share Posted June 12, 2011 You could do the discreet thing, certainly the amp would be happier with an 8ohm load (700w per driver vs 500w). I've thought about doing the same but the only reason I didn't is I didn't want to have to use a certain amp rack for dual 18's and for single 18's. And not use 2 conductor (which I have a lot of) for subs. And if for some reason the 2 signals were different it would stress the speakers. I'm prolly too cautious but I don't really need the hassle. Instead consider using 2 GX7s and use 1 for Left and 1 for Right. That way the ch1 material is different than ch2 on each amp, the power supply will most likely be able to put out more than rated power for the sub channel since the mid/high channel won't be hard to supply. I do this with one of my amp racks and it's been really handy, and running hard @ 2 ohms for mids isn't an issue. Link to comment Share on other sites More sharing options...
Members dboomer Posted June 12, 2011 Members Share Posted June 12, 2011 Other than weight reduction I don't think you'll notice any difference. Link to comment Share on other sites More sharing options...
Members gonzobassman Posted June 13, 2011 Author Members Share Posted June 13, 2011 Lot of money to put out for a little weight reduction,but I think one amp per box makes it pretty user/room friendly. One sub =1400 watts on the subs,two subs =2800 watts on the subs,and the amps will just be "cruising" with their respective 8 ohm loads! Think I'm gonna try it. They will all stay in the same rack,I'll just hook up what I need to run,and go! Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 13, 2011 Members Share Posted June 13, 2011 Don't run 1+/1- AND 2+/2- unless you are very, very careful with what you do at the other end. It's not standard, though it sometimes is done. The companies that do this are generally quite careful. Those that are not become careful once they have an accident. If your tops are biamped, you now run the risk of sub information to the horns (2+/2-) which is a costly lesson. Link to comment Share on other sites More sharing options...
Members gonzobassman Posted June 13, 2011 Author Members Share Posted June 13, 2011 My current sub speaker cables are 50 foot 12-4 with speakon on one end,and banana clips on the amp end.Right now I simply bump the banana clips into each other per cord effectively making it 12-2 wire.I only use these cables on my "big" subs,and I was thinking that by rewireing my boxes,I would simply have to place the banana clip into the respective output points on the amps.Being careful of polarity(sometimes those clips can getcha).The speakon ends are already wired correctly to do this,so its just a matter of rewireing the boxes,and getting the amps. Unless I'm missing something? Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 13, 2011 Members Share Posted June 13, 2011 You are missing the problem of what's going on on your main speakers IF you (or well meaning help) happen to get the sub cable plugged into the main speakers. If your main speakers are biamped, you will have problems. Link to comment Share on other sites More sharing options...
Members gonzobassman Posted June 14, 2011 Author Members Share Posted June 14, 2011 You are missing the problem of what's going on on your main speakers IF you (or well meaning help) happen to get the sub cable plugged into the main speakers. If your main speakers are biamped, you will have problems. AAAHHH Yes! I would have to agree,that could be a big problem! Not bi-amping tops yet(when I can afford to upgrade,I will). Probably more hassle,and money than its worth since I'm so AR that I rarely let anyone help with any wireing except for tear down. One of the few fringes of being small!!! Lol Link to comment Share on other sites More sharing options...
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