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Not sure how to do this

hfc7713hfc7713 Posts: 24
edited July 2012 in PA General Discussion
I hope this doesn't sound like a stupid question.

I know my subs are underpowered and overshadowed by my mids (Gadget has mentioned this too). I have SRX715's and MRX518's. I am tri-amping and it sounds great at low to mid volumes.....However, I am always aware that the subs are a little drowned out by the mids so I just keep the levels down on the mids. I am using XTI4002 on the mids (an old Carvin for the horns) which is more than I need bridged into 4 ohms total but only XLS2000 on the subs. Because they are 4 ohms I am getting 650 output per side. I figured, although it might not make much difference, I would switch the amps - the XLS on the mids and the XTI on the subs. However, from the driverack, only the low out offers mono. This has not been a problem because I have been using left and right out for subs and same for mids even though amp is bridged - it still receives 2 channels. Now if I switch, the XLS will only receive single channel input when bridged but I have left and right from driverack. Is it as simple as using a 'y' connector or will I get signal loss or something worse???????

Comments

  • GadgetGadget Posts: 4,915
    actually, you can choose mono sum and you'll actually have the same exact output from both low outs even if you select mono sum. In that config both otuputs are hot...

    You can also use the through function on many of the amps as well AND use the dual mono function on the amp for non bridged operation.
  • GadgetGadget Posts: 4,915
    Gadget wrote:
    actually, you can choose mono sum and you'll actually have the same exact output from both low outs even if you select mono sum. In that config both otuputs are hot...

    You can also use the through function on many of the amps as well AND use the dual mono (parallel) function on the amp for non bridged operation.
  • hfc7713hfc7713 Posts: 24
    Thanks Gadget.. I only see mono out for the lows - not the mids. The XLS would now be powering the mids and I see no mono out on the DRPA so how will I sum left and right??
  • DraDra Posts: 3,777
    I've juggled the numbers around and pretty much no matter what you do, you are either going to under power the subs or the mids. The biggest problem may be that the SRX cabs are naturally a little louder (2db) given the same power (2/3rds more power required to match).

    A 4 ohm speaker always screws the pooch when you want or need to bridge, because it makes you buy another amp for every speaker.

    Bottom line - The MRX will never keep up with the SRX, unless you add more MRX (and power). Get the subs to the level that you want, then balance the mids and highs to that. "That's all she's got Cap'n"

    DRA
  • hfc7713hfc7713 Posts: 24
    Yep...I know. Those SRX's are pretty nice!!! The system is mis-matched..I get it. Should have just got one SRX sub really in the first place.Oh well.......
    Thanks all!!!!!!
  • DraDra Posts: 3,777
    edited July 2012
    Does the sub amp go into clipping, or does it just fall behind as the output increases? In the the former, then :? . If the latter, then maybe the amps' gain ratios is not the same. Are either of them selectable?

    DRA
  • hfc7713hfc7713 Posts: 24
    When I set gain structure, I have to set up crossover gain way high on the XLS so I can get all the amps to a similar gain setting (knobs on front) and everything clipping together. The DRPA limiter threshold leds light up on the lows unless I turn off the limiters completely or turn the input down. I have the limiters on the amps set to on. Not sure about the gain ratio question. The amps do not clip because I have everything set according to gain structure. The constant flickering of the limiter threshold LEDS on the lows does worry me a little.
  • DraDra Posts: 3,777
    edited July 2012
    Setting gain structure really means little, as it applies to system balance (HML). The reason that the system sounds good at low and med volume is that the limiters on the XLS (DR output) have not kicked in yet. (This is the first time you mentioned the DR low output being in heavily limiting at high volumes.)

    If you are running live sound you might consider turning off the limiters on the DR's low outputs all together. Turn on the clip limiters on on the amp itself and let it ride. That may improve the sound to a higher level. If you wish to push the envelope, you might try turning off the amp's limiters all together. Here's why. A clipping amp will output about double the rated power. In your case, about 1300w. Still well below you peak rating, and as long as the clip lights don't glow on (flashing with the kick drum is fine) you would gain even more output and be balanced. Many people like the "dirty / distorted" sound of a sub amp clipping a bit.

    Take this info under advisement, because if you loose control and run the sub amp into full clip mode (clipped more than not clipped) the subs will be cooked (well done).

    If these 2 changes don't give you the balance you need, you MUST turn down the other amps.

    Be prudent.

    DRA
  • GadgetGadget Posts: 4,915
    As Dra said, setting the limiters on the amps lowers the output capability by about 1/3 (usually) My RMX 2450's drop to about 1600-1700 watts...

    If you do the gain structure properly, then the CLIP points of the amps are BELOW that of the mixer...so, when you see the master output meters nearing +10, you know your running out of gas...
  • hfc7713hfc7713 Posts: 24
    DRA and Gadget...THANK YOU..... This is really what I needed to know. I was just worried about NOT having limiting on everything including the sub amp. DRA, I am very careful and conservative when I run the system so I will go ahead and remove the limiter from the lows on the DRPA and see how I do with them only on the amp. Then if I need more I will turn limiting off the amp and again be mindful of any clipping. No-one else runs the system so I do not have to worry about someone else coming in and turning everything up to #11!!!!! My rule is HANDS OFF!!!
    Thanks again guys!!!
  • DraDra Posts: 3,777
    Please let us know how it goes.
    Good luck.

    DRA
  • hfc7713hfc7713 Posts: 24
    OK So........... just got another xls2000 today. Going to use the XTI on the subs in stereo. Then the Carvin for the highs in stereo and one XLS bridged on one side and the other bridged on the other side for the mids. Wiring it all up tomorrow and looking forward to it!!! I' m pretty annoyed though that I need to get a bigger rack now to house the fourth amp. Till then I'll use my 4 U to house the XTI and connect to DRPA, power supply and speakers each gig. I should get a lot more out of the subs right????
  • DraDra Posts: 3,777
    The XlS was providing 650w. The Xti will provide 1200w. That's about double, so you 'll gain 3db.

    DRA
  • hfc7713hfc7713 Posts: 24
    Thanks DRA......Wired it all up and sounds great. I feel that although it is only a 3 db gain, the system is better balanced now between the mids and the lows. I may have to push the subs a little to cut through at high volumes but at least I have the means to do it now. One day, I'll get a couple of SRX 718's (or equivalent) and I'll be good to go!!!!!
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