glennrush

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About glennrush

  1. On the advice of this forum, I am running two JBL 728 subs with 1 ma 9000 I. This is just great stuff....couldn't be happier. My question is that many venues we play could actually use a bit more. Our sound guy has a pair of older SR4719 subs. Two questions.......1. How do you feel about running 4 subs on this amp at 2 ohms a side?? And 2. Anybody have any thoughts on pairing the 728's with the 4719's?..
  2. Hey Jon, using a drive rack PA Hi Glenn What kind of processing are you using?
  3. Thought I'd close the loop on this one. I bought the MA9000i to power 2 SRX728S subs (4 ohms each) in stereo. Used the xti6000 to power a pair of SRX725 tops also in stereo at 4 ohms. All I can say is OMG!!!!!!!! What a kick-*beep* system. Plenty-o-headroom to be sure and clean and punchy... Thanks for the advice....this was the ticket.
  4. I have a older (three years) entry level drive rack. I use as much of the manufacturer recommended timings that my drive rack will allow. What do you use for processing? how are you tuning everything?
  5. Thanks ndakos, good stuff. I purchased the MA9000i before I saw your post so I'm kinda committed at this point. Hope you agree with Kevin that this will do nicely, 3500 watts per side into 4ohms. Byt he way what do you think of a single xti 6000 powering a pair of JBL 725 tops?? quote name='dakos' date='Oct 4 2011, 04:39 AM' post='15237'] Dear glenn0, Every kind of music needs a bit of "Amp headroom" for peaks in the music, that number ranges from a minimal +3db (two times the wattage) for the most compressed coffee house music, up to +24db for uncompressed live band shows. Amps have almost no headroom built in them while speakers do, that's why you need an amp at least twice as powerful as your speakers, especially for sub duty, that's why a couple of 4000/4002 are not a good match for two 728's and the 6000/6002 are better. Despite the i-tech's haveing a bit of headroom built in them for those peaks, I'm not sure a single the 9000HD is better, I think a single 8000 or the 12000 just might be enough. For a single amp application you need to connect the two 728's to get 8 ohms total and then you need 6400W plus a bit of headroom to run it all, The 9000HD will give you 7000W at 8 ohm bridged. The 8000 will give you 8000W at 8 ohm bridged. The 12000HD will give you 9000W at 8 ohm bridged. They all have a little extra headroom built into them. For a two amp configuration, you need to connect each of the 728's to a single bridged amp at 4 ohms each so you need at least 3200W from each amp plus the headroom, Two 6000/6002 will give you a total 12000W at 4 ohm bridged total. Two 4000/4002 will give you a total 6400W at 4 ohm bridged total. On this configuration you have almost no amp headroom. The headroom is also the reason working with a compressor such as the DRPA+ would be advised since it would compress the peaks in the music to a reasonable level so the amp and speakers would be able to handle without the amp clipping or putting the speakers into over excursion. IMHO for the best $$$ for Watts, I suggest you try to get a used i-tech 8000, they run for about $1700-$2000. Next runner up is the 2X6002, they are about $1525 each on eBay, you will get all the power you need + the headroom for the subs to sound great. Using DRPA+, even the DRPX would suffice for your application, is extremely wise!! Kevin, please correct me if I'm wrong...
  6. Thanks Kevin, I took your advice and bought the MA9000i for my subs. I'll let you know how it all works out. quote name='Kevin Heber' date='Oct 3 2011, 02:52 PM' post='15230'] 3200W is the recommended power, and 4-ohm/bridged is the most demanding load these amps will tolerate. It's like hauling a large trailer up a mountain with a sedan.
  7. I'm confused, I thought that bridged at 4 ohms, that the xti 4000 puts out 3200 watts, this is the bare minimum for the JBL 728 subs?.
  8. Kevin how do you feel about using 2 xti4000 amps bridged to power a pair of srx728s subs, one amp per sub???
  9. I get it, I think. Thanks for the education. I'll need a different solution.
  10. Kevin, why is that?? All 3 subs are a 4 ohm load. If I bridge the amp and series the EAW's I get back to 8 ohms if I then parallel the 728 To this load i get 6 ohms. The amp sees one load, why more power in the 728? If this is the case I need another solution.
  11. You want to run 5 subs off one amp? Yes, that is crazy. I'd skip the SRX, center cluster EAW's, run in stereo and cross your fingers. You'd still be underpowered but it should give you better sound. no no no, i said that wrong, my mistake, Total of 3 subs two on each side one center. Recently saw a guy running 4 JBL SRX728s on one Xti6000 at 2 ohms outside no less. sounded great. I am currently using one xti6000 for my tops (EAW LA460's) and 3 QSC 3602 bridged, one for each sub and they still thermal out. Hate the QSC amps thinking about going to one Xti6000 for the subs.. waddya think?? I mean 1 LA 128z on each side (jeeeesh I did it again)
  12. You want to run 5 subs off one amp? Yes, that is crazy. I'd skip the SRX, center cluster EAW's, run in stereo and cross your fingers. You'd still be underpowered but it should give you better sound. no no no, i said that wrong, my mistake, Total of 3 subs two on each side one center. Recently saw a guy running 4 JBL SRX728s on one Xti6000 at 2 ohms outside no less. sounded great. I am currently using one xti6000 for my tops (EAW LA460's) and 3 QSC 3602 bridged, one for each sub and they still thermal out. Hate the QSC amps thinking about going to one Xti6000 for the subs.. waddya think??
  13. OK no laughing at my question please. I have an xti6000 and I would like to run 2 EAW LA 128z subs on each side of the stage and one JBL SRX728s as a center sub. No way I can match that to 2, 4, or 8 ohms. But I can make it 6 ohms by connecting two of the subs in series and then paralleling the remaining sub for a total of 6 ohms. Run the amp in bridge mode. Is this totally crazy or is it acceptably to mix series and parallel connections in this way to get the ohmage to an acceptable level? Any other suggestions?.
  14. Hey Kevin, had a bunch of gigs using a house pa, finally got back to your suggestions. You know I used to think I knew what I was doing but man I am not so sure anymore, hope you can help. Recall I am using the following 1 Xti 6000 in stereo into 2 EAW LA640's 2 Xti4000's bridged one each into 2 EAW LA 118z's (i think, 2 18's/cabinet anyway) Bandmanager Mackie 24x4 onyx board 1. I am assuming that I want the input and output meters in BandManager to somewhat match on all 3 amps with pink noise. Meaning that when the input is 2 bars into the yellow, so should the output bars. 2. As you suggested I ran pink noise into my board and made sure the output meters read 0 db. Bandmanager input meters on all three amps was about 2 bars into the red. 3. Under these conditions, XTI 6000 output meters in BandManager (amp knobs on full) reads 2-3 yellow bars while the XTI 4000 output meters in BandManager (amp knobs on full) reads very low, only 2 bars in green. Have to boost crossover gains (set at 20 and 85 hz) 12 db to get output and inputs to somewhat match (2 bars into yellow, like the Xti6000). Is this because I am using pink noise as my source or is this OK?? Twelve db boost seems just crazy. I feel humbled, I thought I knew what I was doing but obviously there are some things here I do not understand, I would greatly appreciate any help in how I balance this system so I protect and get the maximum performance out of my equipment. Glenn
  15. Hi Kevin, glad I got you. I know, keep thinking I am doing something stupid, but I dont know what it is?? I dont have the ability to do this right now, no sine wave generator. What I have done in the past to set gain structure is to run pink noise into a chanel, set the board channel gains until I am just cliping then adjust all of the gains in the signal chain until they were just clipping and thus have a more-or-less gain balanced system. When I try to do this, I just red-line the input indicators on bandmanager, and presumably the amps (all of them). Could this be an inout sensitivity setting issue?? Setting all of your channel gains to just below clip is why you can't push your master to unity without clipping. Try setting the channel gains to were they just start to flicker the +3 light on the meter. You should be able to run at unity with no issues. You'll probably find that your mix will sound better as well. Only setting the gains just below clip for calibration. During performance we are well below clipping any of the channels/components, except for the input gains on the amps, very odd. Still think I am doing something stupid and havent realized it yet!!!