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Speaker processor in Amp rack or...

Discussion in 'Sound, Music, and Intercom' started by Anonymous067, Dec 18, 2008.

  1. Anonymous067

    Anonymous067 BANNED USER

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    Wheres the best place for the main processor?

    I'm designing a small semi-portable system and can't really determine if I should put the Driverack PA (dbx) on top of the amp rack or leave it in the other rack with the eq feedback etc etc.

    System is composed of two 21RU rolling racks.

    My only thought is if I put the unit with the amps, I save on cable lengths because ideally I want all connections to be extendable so that the two racks can be 15 feet apart. If I have to run from rack to rack and run highs mids and lows....yeah....

    thanks.
     
  2. avkid

    avkid Not a New User Fight Leukemia

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    In the amp rack.
    If you think that you need to be adjusting it during a show, you're doing something wrong.
     
  3. Anonymous067

    Anonymous067 BANNED USER

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    Well.
     
    Last edited: Dec 22, 2008
  4. TimmyP1955

    TimmyP1955 Active Member

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    Why have an EQ for the house when there's already one in the DriveRack? In which case you need the DR in the FOH rack.
     
  5. Eboy87

    Eboy87 Well-Known Member

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    DSP in the amp rack, house graphic at FOH (unnecessary with digital consoles). That's the way I see it done.
     
  6. museav

    museav CBMod CB Mods Departed Member

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    I'm a big fan of putting system DSP in the amp rack and away from prying fingers and having separate processing at FOH. However, in a basic portable setup where the DRPA will be used for the overall system tuning and not just speaker tuning, it may make more sense to have it in the FOH rack. Better yet, get a DR260 instead of a DRPA, mount it in the amp rack and run it from FOH.
     
  7. mixmaster

    mixmaster Active Member

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    I've seen it done both ways. Most of the Pro crews I have seen it's in the FOH rack and there is a different snake (called a drive line) going directly to the amp racks.
    Putting it in the amp rack saves return lines to the stage. If you don't ever plan on messing with it, ever, having it up on stage is fine. It gets it out of the FOH rack, where the room may be needed for other equipment. It becomes a problem however, if there are things that you want to do with it during set-up and soundcheck. You'll waste a lot of time running back and forth to the stage to make those changes.
    OTOH you could put it at FOH. The two biggest problems are the extra return lines that you need to have, and the extra space that the thing takes in your FOH rack. The benefit is being able to use and adjust it during your event.
    I have often heard that nothing on a DSP needs adjusted after it is set and I disagree. If you are using the delays to align drivers in the boxes, they stay set, but if you are using the delay to align the cabs to the stage, that will change on a regular basis. PEQ per output is is determined by the drivers and cabs, any EQ system wide would vary per venue. I know the DRPA has a function that uses a pink noise generator to "auto set" the FOH graph and that would be better operated from FOH. For troubleshooting, being able to mute and unmute individual outputs is nice, and I always like to have as many meters where I can see them to confirm gain structure. Two other advantages to DSP are they're ability to recall setting per venue, and the ability to set limiters and other controls per show and lock them out or not. Both of these require access to the DSP which would be awkward at best if your unit is in the FOH rack. I also like the idea of having it available for tweaking during the first few shows, since you'll be making adjustments on the fly for a while.
    Personally, I prefer the DSP in the FOH rack, unless it is a simple crossover, or an installed system where it is truly set-and -forget.
    Matt
     
  8. Anonymous067

    Anonymous067 BANNED USER

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    My loose "eq" was actually my 4 channel for my monitors. Sorry for the confusion.
     
  9. museav

    museav CBMod CB Mods Departed Member

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    In my experience, most pros put the DSP at the amp rack and remotely control it. One of the major limitations of the DriveRack PA, and why many people recommend moving to the 260 or better if possible, is that it does not allow such remote control.


    It is indeed important to realize that system tuning is potentially more than just EQ. Although it can be broken down even further, I like the concept of looking at system tuning as potentially consisting of four general components; box, array, environment and artistic. The box tuning is usually done to get a nominal response for each speaker and once set should not have to be adjusted. Array tuning addresses how the multiple boxes in the system work together. If you have a fixed system configuration then this may be preset and left alone, if the configuration changes then some elements of the tuning may also have to change. Environment tuning addresses both the room in general and specific issues such as the effect of surfaces near speakers, thus it may be general to all of the system or specific to individual devices and may be fixed or variable depending upon whether the installation is fixed or changing. Finally, the artistic tuning is the subjective adjustments that may change from artist to artist or even during a single performance, it is getting the desired sound for a specific use much more than optimizing the system itself.

    In the above approach there are several layers of both fixed and variable tuning and this is where I think more advanced processors have a major advantage as they can be configured exactly that way, with multiple 'blocks' of related processing, some of which may never need to be touched once set and others which can then be adjusted without directly affecting the fixed processing. Unfortunately, more basic DSP devices do not support this approach which is why I typically try to separate the more fixed system processing that an operator should not have to normally adjust from the more routinely adjusted processing that is located at FOH.

    If this separation is not possible then one consideration may be who is accessing the processing. If it is someone you can trust to not negatively impact the processing already applied, then it may make sense to have it located at FOH. If you are concerned about someone getting in an messing with the basic system processing, say adjusting output limiters or playing with crossovers, then it may be best to have it located in the amp rack and secure from such users.


    Or even better, not operated at all! Seriously, from only being able to address one listener position to being limited to the graphic EQ to trying to use EQ to correct for phase and modal issues, the AutoEQ function in the DRPA is very limited and easily misapplied. It can be useful if you are aware of the limitations but most people relying on AutoEQ probably are not that knowledgeable.
     
  10. hsaunier

    hsaunier Active Member

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    Seems that most have placed the DSP in the Amp rack. We like to place the amp rack with the DSP on the same side as monitor world. At least then someone (mon eng) can lay eyes on the meters.
     
  11. waynehoskins

    waynehoskins Active Member

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    I tried it once; it sucked. Auto EQ should be labeled "Auto Suck". I pinked it a couple of times, and it made some really harsh curves on the graph. After two rounds I said "Enough" and zeroed it out and did it by ear with music I knew. Much better.

    As to where goes the DSP, I too like it in the amp rack(s) with a graph at FOH. Now I have mine at the church back at FOH, and it is a DRPA, mainly because every now and then I will adjust something. In particular, I have three presets in the thing: Normal, Ten, and Eleven. Those just adjust the output gains so I can run the console (and thus recording world) at 0dB all the time, but go from semi-conservative Sunday morning levels (high 90s?) to wide-open rock-and-roll Eleven. But that's just me.
     
  12. airkarol

    airkarol Member

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    I would put the DSP in the amp rack, with a lock outon the front panel controls. If this is a fixed environment, once set it shouldn't require any change. If it's mobile, you'll need to adjust for different rooms before a show, but once the show starts, you shouldn't be touching it at all.

    If you have the budget, go for the DR260. That $400 (estimate) difference is definitely worth it.

    Also, see if you can purchase a graphic equalizer. The DBX 1231 isn't bad, and it's not too costly either. Keep that at FOH. If you need to quickly notch someone out, or a guest engineer is mixing, then it's a great thing to have. That way, you also don't have to worry about hitting the wrong button on the DSP.
     
    avkid and (deleted member) like this.
  13. mixmaster

    mixmaster Active Member

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    [QUOTE=museav;11566


    Or even better, not operated at all! Seriously, from only being able to address one listener position to being limited to the graphic EQ to trying to use EQ to correct for phase and modal issues, the AutoEQ function in the DRPA is very limited and easily misapplied. It can be useful if you are aware of the limitations but most people relying on AutoEQ probably are not that knowledgeable.[/QUOTE]

    My reference to the DRPA was for illustrative points only. I tend to look askew at anything that happens "automatically" Come to think of it, I've worked with several groups come in who were less than happy with their DRPAs for a variety of reasons....

    The OP also specifically mentioned that the DSP in question was the DRPA. Since it doesn't have the remote control functions that most "pro" DSPs support, putting it in the amp rack means any of your environmental and artistic concerns would have to be changed by running back and forth to the amp rack. In a perfect world that may still be OK but in the real world of short notice shows and last minute changes, I want as much control at my fingertips as possible. I would still recommend DSP in the FOH rack.
    Matt
     
  14. museav

    museav CBMod CB Mods Departed Member

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    I think this touches on a subject brought up in another thread. If it is your system and you will always be the operator, then having the processor at FOH may indeed have benefits. But if the system may be used by operators of unknown skill and/or by those who aren't responsible for the system, then limiting access to and separating the system processing, even if it costs more, may be well worthwhile. As with many things, the specifics of the application may well affect what is the optimal solution.

    Put simply, if it was my system that only I ran or if I was the FOH engineer, then I'd probably want the DRPA at FOH. But if I was the House engineer or if it was my system and I had little or no control over who ran it, then I'd probably want the processor as far from FOH as possible, even if it meant also having an additional EQ, etc. at FOH for the operator's use.
     
  15. mixmaster

    mixmaster Active Member

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    Another thought that comes to mind, what if you end up with more than one amp rack? Which rack does it go in? When I was out on the road, the full system had two amp racks on each side of the stage, FOH control down a 12 pair driveline. For medium shows, we could take out half the rig, and do one rack per side. For club gigs, it was one rack total, driving both left and right. If we did delay towers, that was another amp rack per tower. With the DSP in the FOH Drive rack, it didn't matter which amp rack we grabbed to put where. While this example is currently beyond the scope of the OP, it demonstrates additional flexability should he ever get bigger.
    Just a thought.
    Matt
     
  16. Eboy87

    Eboy87 Well-Known Member

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    At school, we keep all our XTA's in a separate driverack (two of them actually). I guess Mixmaster and I are in agreement with that, but we keep said rack back in amp land, and control it remotely with AudioCore. PITA to get that program running with ethernet, but totally worth it. We keep a few Klark-Tekniks in the rack by FOH.

    When we pull the system apart and send part of it out on a show, we just grab one driverack and amp rack, and we're off to the races.
     

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