Members vaughn4380 Posted July 19, 2011 Members Share Posted July 19, 2011 Someone was nice enough to donate a pair of Yamaha SW118 subs for the teens' room at church? In a quick effort to get them up and running, the staff thought two Crown XLS 1000 amps each bridged to 1100 watts mono would be excellent and asked the adult worship department to hook them up once they came in. Thankfully a quick google search revealed that the subs are more like 300 watts RMS and the Crowns were returned without opening the boxes. Due to this mistake, we have been asked to order a correct amp and I was thinking about the GX3 from QSC. There will be no external processing or limiting in place in the system, only the Yamaha mixer running into the GX3 with the internal crossover engaged. They currently have two GX3s they use running two S115V FOH speakers (off one amp in stereo, full range) and four SM12V monitors (off the second amp, 2 mixes, also full range). So another GX3 would be familiar. I was hoping to keep to the 300 watt RMS as much as possible for the subs, but since the subs are 4 ohm cabs, the GX3 will put out 425 watts to them in stereo. Is this too much without a HPF of some type? I also read the instructions for the GX amps and it looks like I will need to rewire the S115s so that one GX3 amp will be running one S115 and one SW118. I imagine this won't be an issue running one 8 ohm cab on channel 2 and one 4 ohm cab on channel 1? Thanks! Just want to get this right. Link to comment Share on other sites More sharing options...
Members vaughn4380 Posted July 19, 2011 Author Members Share Posted July 19, 2011 Oops, looks like Yamaha's website says the subs are 8 ohms, not 4. Looks like the kids' Pastor might have misread the specs when he was telling us the impedence. The only four ohm subs I see on the website are the dual 18's. So they would have been getting around 700 each with the Crown XLS1000s, still too much. But it looks like the GX3 might be a great option? Or would a GX5 be better, run two speakers on each channel (with the crossover engaged, S115s on channel 2 and SW118s on channel 1), and give each speaker 350 watts? We would lose the stereo output but I don't think they would care. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted July 19, 2011 Members Share Posted July 19, 2011 Are you sure they are 4 ohms? I don't remember a 4 ohm single 18 Yammy club? In any case you really should have a HPF for them if you want them to last . Link to comment Share on other sites More sharing options...
Members Coaster Posted July 19, 2011 Members Share Posted July 19, 2011 i'd probably aim for the 400 watt range on those, keep in mind they are not robust subs and have poor cabinets. Link to comment Share on other sites More sharing options...
Members jlb Posted July 19, 2011 Members Share Posted July 19, 2011 Oops, looks like Yamaha's website says the subs are 8 ohms, not 4. Looks like the kids' Pastor might have misread the specs when he was telling us the impedence. The only four ohm subs I see on the website are the dual 18's.So they would have been getting around 700 each with the Crown XLS1000s, still too much. But it looks like the GX3 might be a great option? Or would a GX5 be better, run two speakers on each channel (with the crossover engaged, S115s on channel 2 and SW118s on channel 1), and give each speaker 350 watts? We would lose the stereo output but I don't think they would care. This would be a good match and you only need one amp/crossover. Like Coaster said they are not robust. I think they only have 2.5" voice coils. You could still damage them with 350w if you aren't careful. Link to comment Share on other sites More sharing options...
Members Rezrover Posted July 19, 2011 Members Share Posted July 19, 2011 Could get a decent used crossover for fairly cheap too. Link to comment Share on other sites More sharing options...
Members vaughn4380 Posted July 19, 2011 Author Members Share Posted July 19, 2011 Are you sure they are 4 ohms? I don't remember a 4 ohm single 18 Yammy club? In any case you really should have a HPF for them if you want them to last . I think you are right, I was given the specs by the Teen Pastor and I can't find any single 4 ohm subs either. I do know they are single subs as I have seen them sitting on the stage. I would like to HPF them, but that would require an external processsor of some type. Since these will be run by teens with little experience, and they have no external stuff to mess with right now, it might just add confusion. Link to comment Share on other sites More sharing options...
Members vaughn4380 Posted July 19, 2011 Author Members Share Posted July 19, 2011 This would be a good match and you only need one amp/crossover. Like Coaster said they are not robust. I think they only have 2.5" voice coils. You could still damage them with 350w if you aren't careful. I could just hook them up with the current GX3, give each sub 212 watts off of channel 1 and each S115V 212 watts off channel 2. Might keep the kids from frying anything (at least for a few months). Link to comment Share on other sites More sharing options...
Members Unalaska Posted July 19, 2011 Members Share Posted July 19, 2011 I'd prolly just get a GX5 and use 1 channel per sub (500w) and an external crossover. Maybe get a security cover for the crossover and dime out the amp attenuators. Link to comment Share on other sites More sharing options...
Members agedhorse Posted July 19, 2011 Members Share Posted July 19, 2011 Either the GX-3 or 5, the 5 would be a better match IF you needed the extra volume. Otherise if the volume is sufficient without hitting the limit LEDs a lot, the GX3 is fine. Link to comment Share on other sites More sharing options...
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