Members oachs83 Posted January 17, 2015 Author Members Share Posted January 17, 2015 Hey Comoxsam, I am taking your advice. I just purchased a DBX 223s crossover as well as a DBX 231 31 eq (both used got both for $150). Which still lies I need a power amp to run at least my subs. I believe that is what is being recommended? Here is where I am asking questions on amp output. The Alto mixer I have on their site that says it has 750w at 4 ohms then in parenthesis says 520w RMS at 4 ohms. So that is telling me it's real wattage is 520w RMS at 4 ohms which means it is even less at 8 ohms. So when I hook it up to my lets say left main at 8 ohms that is rated 400w RMS I will at least be matching my RMS but not near the recommended 50% above RMS power. That is why I have been asking about the GX7 to run both mains and subs in 4 ohms as it seems closer to the recommended power rating for both. Otherwise it looks like the GX5 alone running my subs at 4 ohms would be great but not sure. My question was kind of directed towards if I should spend the money on a GX7 now so I at least have the power if needed or if it looks like a waste of money? Thanks again guys. Link to comment Share on other sites More sharing options...
Members wesg Posted January 17, 2015 Members Share Posted January 17, 2015 Comoxsam, how is he supposed to keep the low frequencies out of the tops with that configuration? Link to comment Share on other sites More sharing options...
Members Comoxsam Posted January 17, 2015 Members Share Posted January 17, 2015 Wesg Stratguru's earlier post is what I was referring to. "Right under the big "TMX" label is a pair of jacks that says "ST out" you want to use a couple of TRS cables to go from there to your crossover. Then from the crossover, one pair of signals go to the power amp that will power the subs. The other pair of signals will go back to the mixer and plug in where it says "P Amp Input" that way the lows are being sent to the subs and the rest will come back to the power amps in the mixer." Link to comment Share on other sites More sharing options...
Members Comoxsam Posted January 18, 2015 Members Share Posted January 18, 2015 Hey Comoxsam, I am taking your advice. I just purchased a DBX 223s crossover as well as a DBX 231 31 eq (both used got both for $150). Which still lies I need a power amp to run at least my subs. I believe that is what is being recommended? Here is where I am asking questions on amp output. The Alto mixer I have on their site that says it has 750w at 4 ohms then in parenthesis says 520w RMS at 4 ohms. So that is telling me it's real wattage is 520w RMS at 4 ohms which means it is even less at 8 ohms. So when I hook it up to my lets say left main at 8 ohms that is rated 400w RMS I will at least be matching my RMS but not near the recommended 50% above RMS power. That is why I have been asking about the GX7 to run both mains and subs in 4 ohms as it seems closer to the recommended power rating for both. Otherwise it looks like the GX5 alone running my subs at 4 ohms would be great but not sure. My question was kind of directed towards if I should spend the money on a GX7 now so I at least have the power if needed or if it looks like a waste of money? Thanks again guys. Hi Oachs83 Sounds like a decent deal on the EQ and Xover. Next you need an amp for your subs. I'm not sure but I think the two amps you referenced have built in crossovers. The GX5 would probably work for your subs. In regards to the specs on your Alto mixer you never really know what you are getting. As others have indicated its a real crap shoot as the manufacturers numbers aren't accurate and are used to generate sales. In other words they are lying. Once you start using a separate amp for your subs and use the crossover to separate the highs (to your mains) and lows (to your subs), the amps in your mixer may not be as underpowered as they seem. All I'm saying is give it a try first before you start buying more and more stuff. Link to comment Share on other sites More sharing options...
Members StratGuy22 Posted January 18, 2015 Members Share Posted January 18, 2015 Nice to meet you nchangin, I live in Mankato. Thanks for the tips. Here is a link to our band site http://www.thewhiskeyrichardband.com/ if anyone was curious. So I found a awesome deal on a QSC GX5 amp for $175 used. Its rating is 700w at 4 ohms and 500w at 8 ohms. This seems a little light for what I have been told lately if I am going to run daisy chained two 400w mains and two 350w subs. Still is much better than what I have. Otherwise for just under $400 I found a QSC GX7 that is 1000w at 4ohms and 725w at 8ohms. Is a GX5 worth the buy or will I just be wasting money? Instead of running the mains off one channel, and the subs off the other, simply pick up another amp. Have one properly sized for the tops, and another one the proper size for the subs. Might as well do it right! Link to comment Share on other sites More sharing options...
Members agedhorse Posted January 18, 2015 Members Share Posted January 18, 2015 Oh no, don't do it right.. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted January 19, 2015 CMS Author Share Posted January 19, 2015 In regards to the specs on your Alto mixer you never really know what you are getting. As others have indicated its a real crap shoot as the manufacturers numbers aren't accurate and are used to generate sales. In other words they are lying. ...or in many cases, their specs aren't lies, but are only true under a very narrow set of circumstances. An analogous example is the way shopvacs (by that brand name as well as other brands) seem to have impossibly high horsepower ratings for those tiny little motors. It seems they got that rating by determining that if the motor shaft was suddenly stalled while running, the current draw will momentarily spike. By extrapolating that current draw spike into a horsepower rating, they come up with the number printed on the box. Nothing is mentioned about the fact that the motor will quickly overheat and fail at the point where that rating is achieved, or that the motor shaft isn't even turning. But it's not a lie..... Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted January 19, 2015 CMS Author Share Posted January 19, 2015 Hey Comoxsam, I am taking your advice. I just purchased a DBX 223s crossover as well as a DBX 231 31 eq (both used got both for $150). Which still lies I need a power amp to run at least my subs. I believe that is what is being recommended? Here is where I am asking questions on amp output. The Alto mixer I have on their site that says it has 750w at 4 ohms then in parenthesis says 520w RMS at 4 ohms. So that is telling me it's real wattage is 520w RMS at 4 ohms which means it is even less at 8 ohms. So when I hook it up to my lets say left main at 8 ohms that is rated 400w RMS I will at least be matching my RMS but not near the recommended 50% above RMS power. That is why I have been asking about the GX7 to run both mains and subs in 4 ohms as it seems closer to the recommended power rating for both. Otherwise it looks like the GX5 alone running my subs at 4 ohms would be great but not sure. My question was kind of directed towards if I should spend the money on a GX7 now so I at least have the power if needed or if it looks like a waste of money? Thanks again guys. The GX7 would be a good match if you run both subs and both mains with it. The bonus is that the GX7 is actually lighter than the GX5 and GX3 (different amp topology). Link to comment Share on other sites More sharing options...
Members Unalaska Posted January 20, 2015 Members Share Posted January 20, 2015 I have 2 of the alto D4 power amps which are the same amps as in the mixer, they are excellent on monitors and are lightweight too. I'd say they're a bit more powerful than the qsc plx1602 (300 @ 8) and certainly smaller than 2 of them. Not my first choice for subs/tops power. Qsc gx7 or gx5 would be fine, mono, using the internal crossover in the amp. Link to comment Share on other sites More sharing options...
Members Shaster Posted January 21, 2015 Members Share Posted January 21, 2015 Oachs 83, as I mentioned earlier I have a mixer similar to yours - in fact I didn't realize how similar it was, in that yours also has four power amps. I also mentioned that I still use my mixer (Yorkville PM16) for casuals and party gigs, or for quick setups (Stratguy22 owned one as well IIRC) I have used that mixer with power amp and subs, powered speakers, powered subs and so on. Probably your easiest option is to use the mixer as intended - two mains and two (or two pairs) monitors. I would then suggest getting one (to start) powered sub and calling it a day. If you can aux feed the sub, great - sorry I'm not going to read the manual at this point. If you want to add a crossover, that's fine, but it's taking away from the simplicity of the mixer. To restate - mains off of two internal amps, monitors off of the other two internal amps. Bring down the lowest or two lowerst sliders on your FOH graph, aux feed one powered sub either with or without crossover, and as I stated (and still believe) concentrate on your vocal sound and getting a decent enough kick sound to get them dancing. Then concentrate on your monitors and only then start thinking about micing more things. That process might take six months to a year IMHO. A year from now, if you're really getting the hang of it, you might want to sell everything and start over with powered, which is why I suggest starting with a powered sub. However, you can go the power amp route as well, but I would use it for the subs. BTW the power ratings on speakers are for maximum amounts. Unless your are so underpowered that you are distorting the speakers beyond reason, there is NO danger of underpowering. If it sounds good it is good - unless you see or smell smoke EDIT - I guess I should mention that distortion does not destroy speakers, otherwise guitarists would have to buy a new speaker after every gig. Providing too much power to a speaker through "massive" power amp peaks and spikes,is what you want to avoid. Link to comment Share on other sites More sharing options...
Members Comoxsam Posted January 21, 2015 Members Share Posted January 21, 2015 ...or in many cases, their specs aren't lies, but are only true under a very narrow set of circumstances. An analogous example is the way shopvacs (by that brand name as well as other brands) seem to have impossibly high horsepower ratings for those tiny little motors. It seems they got that rating by determining that if the motor shaft was suddenly stalled while running, the current draw will momentarily spike. By extrapolating that current draw spike into a horsepower rating, they come up with the number printed on the box. Nothing is mentioned about the fact that the motor will quickly overheat and fail at the point where that rating is achieved, or that the motor shaft isn't even turning. But it's not a lie..... I think George Constanza once said, "It's not a lie Jerry, if you believe it..." Link to comment Share on other sites More sharing options...
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