Limiter on aux send to sub

Discussion in 'Recording/Live Sound' started by Badstrat, Feb 5, 2018.


  1. 335guy

    335guy Member

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    As an alternate to using the Driverack, you could consider the inexpensive DBX 266XS for the sub only. It has a peak stop limiter, as well as compression. Since your Mackies already have speaker protection, you don't really need a peak stop limiter for those. But you could use one side of the two channels of the 266XS for the Mackies if you ran them in mono. There's also the Behringer CX3400 crossover that has limiting. The downside is, it's Behringer and the low cut is set to 25 Hz.

    IDK what you're using for a crossover for your sub. Many are two channels stereo and three channels mono. And most have adjustable freqs ranges + a low cut. The DBX units use a 40 Hz low cut, while some others use 25 Hz.
     
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  2. Badstrat

    Badstrat Member

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    Will the auto eq function of the Drive Rack work independently for left and right channels. I’m only running the tops mono so the drive rack might be worth it and nice to have all that in 1 rack space.
     
  3. 335guy

    335guy Member

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  4. 335guy

    335guy Member

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    BTW, if you're considering getting a Driverack, it maybe worth a telephone call to DBX support to ask questions, because your speaker setup is a hybrid of a passive sub using an amplifier, and active main speakers.
     
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  5. jmoose

    jmoose Member

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    No.

    And the advice and splitting L/R for subs vs tops is well... questionable. Been debated here many times. No legit sound company sets up that way for good reasons. I'll leave it at that.

    I am a fan of aux fed subs "IF" they're setup and calibrated correctly otherwise I'd much rather run a standard system.

    To setup aux fed subs you need independent processing for both the subs and tops. Two sets of crossovers, system EQ, limiting and a way to keep the volume balanced/cal'd through the entire range of volume. Requires a lot more gear, processing and most importantly knowledge.

    The driverack or similar (BSS Omnidrive etc) running a stereo setup is going to sound better and do a better job of protecting the overall integrity of the rig then a kluged aux fed setup. Hooking up and running the way you have been, anyone will have the risk of blowing up gear again. Especially if you're in a situation where you're mixing from the stage and can't really hear what's actually happening.
     
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  6. Badstrat

    Badstrat Member

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    Well I could just run the system in a standard config. I emailed DBX support and they emailed straight back within 20 min
    “ The PA2 will work fine with powered and passive speakers, in combination as well. This would be fine for you to use!”
    Maybe I should get two cause auto eq and feedback suppression on my monitor might be good. Ide still keep the 31 band just in case.
     
  7. walterw

    walterw Gold Supporting Member

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    that you can't reach down and adjust without scrolling through menus on a tiny screen? no thanks
     
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  8. walterw

    walterw Gold Supporting Member

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    to be fair, those kinds of tricks are for "dudes with mixwizards", not actual sound companies with modern digital boards and proper processing.
     
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  9. Uncle Pat

    Uncle Pat Member

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    Never thought I’d like that piece of fancy gear but man has it been nice. +1 on the Driverack!
     
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  10. rickenbackerkid

    rickenbackerkid Member

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    HPF at 25? no wonder it blew up. I mixed a reggae band on the weekend with a sub array of 14 double 18 subs and I still didn't go that low.
     
  11. Badstrat

    Badstrat Member

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    The crossover only has a button 25hz
     
  12. Geetarpicker

    Geetarpicker Member

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    It’s worth mentioning another important aspect of a high pass filter is its roll off slope. Some are for example 24db per octave, others perhaps higher and some lower. If your HPF has a mild roll off, say only 6 or 12db per octave it simply wont be as effective as one with a steeper slope. If you HPF filter isn’t up to the task either a speaker processor or amp with a flexible DSP might be in order.

    FYI the cheap Behringer NU3000DSP makes a great sub amp (putting out about 2k watts rms in bridge mode at 4 ohms) and it has a variable HPF setting with up to a 48db per octave slope. These amps are a bargain at only $280 new, and the built in DSP is quite amazing for the price as well. I keep one of these as a backup amp, and also a lightweight solution when I just want to add a couple subs or monitors to an existing setup.
     
    Last edited: Feb 12, 2018
  13. sants

    sants Supporting Member

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    I don’t know, seems like all the money you are throwing at the replacement driver and now a driverack, I’d sooner buy the matching sub for your powered tops.

    Might want to rethink the whole setup and look into a digital mixer than adding multiple driveracks.
     
  14. jmoose

    jmoose Member

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    Ironically its the "dudes with mixwizards" who need the processing and protection the most. And real sound companies use the stuff too! It IS proper processing.

    (Raises hand & points towards my own Fisher Price plastic on stick PA)

    DBX has been making driverack boxes for way over a decade. They're dirt cheap used. Whole bunch on reverb for $200 +/- 3dB

    One of the best parts of the newest driverack boxes is the RTA wizard. I'm sure most of us would agree that it'd be great to roll into a room and tune the PA by shooting pink noise but that's rarely possible for various reasons. Need time and a quiet room. The wizard uses a 20-20 sweep that's finished before anyone has time to ask what that noise was.

    I dig aux fed systems if they're setup and tuned well. Usually they aren't. Even by real sound companies. It comes down to time and lack of it. I've mixed on big tri-amped systems for a few thousand people at festivals and other outdoor events... most of them come out of the console into a driverack. Not aux fed. There's usually not enough time to sort it out. Unless there's an artist rider stipulation 95% of the time its stereo mix > rack > speakers

    IME there's too many variables to make an aux fed reliable if your moving PA in & out of different rooms. Way too many if your also mixing from stage...

    Years ago I was production manager at a club that installed a Meyer rig and nearly $30k of acoustic treatment. It took us about three months to get things really dialed in. It was and still is aux fed. That's 90 days of shows 4-5 nights a week mucking with the processor... crossover slopes, system EQ, time alignment, physically moving boxes around and then doing it over again.

    For the average guy like you or me? Way better to smash the boxes of the trailer, stereo into driverack and let the wizard do the work. Fine tune from there. The protection factor alone is worth the dough.

    Lets face it, the OP blew up a nice 1000 watt sub running only a kick drum through it. That's not a mishap, it took some real effort.
     
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  15. WillLane

    WillLane Member

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    I am confused. Isn't this the main problem? If the sub is at 1000 watts continuous @ 8 ohms and it is seeing 1800 watts @ 8 ohms from the power amp, isn't that cooking territory? Is the power amp feeding your tops as well?
     
  16. Badstrat

    Badstrat Member

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    The amp is just for the sub. 1800 Watts would be pushed to the max and is probably only putting out 800 Watts or something when run normally.In the manual for the sub they recommended a 2000 watt amp. You need headroom. A too small an amp pushed into clipping is more likely to cause damage.
     
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  17. Badstrat

    Badstrat Member

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    I'm gonna hold off getting a drive rack for now cause I've got bills to pay. I will be researching digital mixers just so I can better understand the advantages. As for a new powered sub I have very limited space in my trailer so I couldn't get anything bigger than what I have( Turbosound TCX 15b) and it does the job quite well as long as the operator doesn't try to make it sound like two 18" subs.
     
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