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Limiting And the Driverack PX

ksmalk08ksmalk08 Posts: 6
edited December 2011 in DriveRack PX
I know the Driverack PX does not have RMS limiting capabilities like something from BSS - but what setting will give me the "hardest" limiting per se with these "Peak Plus" limiters?

Overeasy On - set to 1

Or

Overeasy Off

Comments

  • GadgetGadget Posts: 4,915
    perhaps a bit more info is necessary...beware, if your looking for protection, limiting is only meant for those OOPS "Sorry man I dropped the mic"... moments.. NOT long term abuse.. not even brick wall limiting will give you that...
    G
  • ksmalk08ksmalk08 Posts: 6
    Specifically what more information do you want?

    I am aware that the PX isnt designed to match the higher end models in terms if its limiting ability - I am just wondering what setting within the limiter menu will give me the most. Does turning overeasy off essentially turn the limiting off as well (meaning a setting of 1 would give me the hardest knee)? Or does turning overeasy off give me te closest thing to RMS limiting that I'll get from the PX?
  • DraDra Posts: 3,777
    "Off" only turn off the "Over-Easy" feature. "Off" is the most abrupt and noticable limiting. As Gadget said the limiter will only catch (limit) the levels that try to jump the threshhold. You can drive the input levels to the point that ONLY the RMS level is at or below the set peak threshold.

    Speaker's Peak voltage = 98v (1200w)
    Speaker's RMS voltage = 49v (300w)
    Amp's max voltage = 69v (600w) Matched to Program rating

    If the limiter is set to stop peaks above the amps 600w output (amp clipping), the input can still be pushed higher. The peaks (for the most part) are being stopped, but the rms level is still increasing, potentially up to the capacity of the amp (600w), double the speaker's RMS rating.

    Set the "peak" limiter for peak voltage and you really have no "real" protection against a stubborn DJ. Set it really low to limit at the RMS value and you will have no usable output without it sounding really bad.

    Without true "rms" limiting capablity the only usable protection is slow blow fuses or breakers between the amp and speakers. Fuses are more precise, but require spares and replacement time at the event. Breakers are more convenient, but they have "can breaker / must break" tolerances.

    DRA
  • ksmalk08ksmalk08 Posts: 6
    Dra wrote:
    "Off" is the most abrupt and noticeable limiting

    The peaks (for the most part) are being stopped, but the rms level is still increasing, potentially up to the capacity of the amp.

    Set the "peak" limiter for peak voltage and you really have no "real" protection against a stubborn DJ. Set it really low to limit at the RMS value and you will have no usable output without it sounding really bad.

    DRA

    Thanks - this is what I was looking for. Much Appreciated.

    if only I had the cash for an Omnidrive...sigh
    The manual for the Minidrive actually has the same example calculation you cited above.
  • GadgetGadget Posts: 4,915
    Yes and every processor will treat those setups differently...every processor will react differently to the exact same presets... every processor will SOUND differently with the exact same presets, so it's important to have processor settings for EACH speaker from the manufacturer developed ON that platform or there will be NO consistency from one rig to another...That IS what were trying to achieve here isn't it? repeatable consistency and cross platform sound quality?

    As for compressor and limiter setups, they are output dependent as well. To set an arbitrary threshold setting without knowing specifically what the system gain threshold is at is pretty useless..Not to mention that if you set it arbitrarily, or using a "suggested" setup from someone, you could have anything from NO affect what so ever to PUMPING LIKE HELL.. or anything in between, to say nothing of the intended purpose of the compression/limiting ... is it for mild softening of the output for effect, or smashing the hell out of it to meet some thoroughly unrealistic SPL limit...

    Further, not all compressors act the same, sound the same, or even react the same to any given signal, so to arbitrarily give out numbers YOU use on your system to others to use on their system is tantamount to teaching painting over the phone... :mrgreen:
  • ksmalk08ksmalk08 Posts: 6
    Gadget wrote:
    Yes and every processor will treat those setups differently...every processor will react differently to the exact same presets... every processor will SOUND differently with the exact same presets, so it's important to have processor settings for EACH speaker from the manufacturer developed ON that platform or there will be NO consistency from one rig to another...That IS what were trying to achieve here isn't it? repeatable consistency and cross platform sound quality?

    As for compressor and limiter setups, they are output dependent as well. To set an arbitrary threshold setting without knowing specifically what the system gain threshold is at is pretty useless..Not to mention that if you set it arbitrarily, or using a "suggested" setup from someone, you could have anything from NO affect what so ever to PUMPING LIKE HELL.. or anything in between, to say nothing of the intended purpose of the compression/limiting ... is it for mild softening of the output for effect, or smashing the hell out of it to meet some thoroughly unrealistic SPL limit...

    Further, not all compressors act the same, sound the same, or even react the same to any given signal, so to arbitrarily give out numbers YOU use on your system to others to use on their system is tantamount to teaching painting over the phone... :mrgreen:


    I am not sure who you were responding to here.

    My initial question was simple - and I got the answer - thanks anyway. I think the information you gave out here was realistic though.
  • GadgetGadget Posts: 4,915
    Yes, I was talking to you.. AND Mr. Dra...I was trying to get you to open up a bit more about what you were trying to do with the compressor/limiting.. you see a lot of LURKERS will read this and think that they can set up the PX to PROTECT their speakers using the compressors or limiters and that will get them into trouble...you too if that is your intention.

    Limiting used improperly can raise the overall duty cycle of the amps, and increase the heat the voice coils are subjected to...thus burning the voice coils, overworking the amps/speakers and reducing their overall life span.. THAT is why I was pressing for info, and answering the way I did...(that and as I said, processor setting are NOT going to be the same cross platform)
    G
  • ksmalk08ksmalk08 Posts: 6
    Gadget wrote:
    open up a bit more about what you were trying to do with the compressor/limiting

    PX to PROTECT their speakers if that is your intention.

    Limiting used improperly can raise the overall duty cycle of the amps, and increase the heat the voice coils are subjected to...thus burning the voice coils

    I really am not trying to do anything as of now - I am just speculating about buying a driverack (might be given a PX as a gift for X-mas) and was reading through the manual of the PX - wondering if it is possible to turn Overeasy off without turning most of the limiting off. The manual talks about the Overeasy limiting but does not go into any detail really about when it is turned off and how the limiter is then reacting.

    Are there any white papers you could direct me to about the "PeakPlus" limiters that I can't find online?

    I use QSC K12's over JBL VRX918SP for most of my gigs - which both have processing - in fact the VRX probably has better processing then the PX, considering it uses JBL's tour-grade DrivePack DPC-2 module. Do you have any white papers/specs on the DPC-2 module?

    How are using two limiters within a signal chain? I have heard generally not considered good (especially like you say, if done improperly)? How about two limiters in a chain if used properly? Are there still some intrinsic issues?

    How would a Driverack 260 compare GENERALLY/OVERALL to a BSS Minidrive FDS-334T if the number of ins/outs isn't critical? I know they are both Harman brands so maybe you can speak to them. (Should I start another thread for this maybe?)
  • DennisDennis Posts: 801
    ksmalk08 wrote:
    I use QSC K12's over JBL VRX918SP for most of my gigs - which both have processing - in fact the VRX probably has better processing then the PX, considering it uses JBL's tour-grade DrivePack DPC-2 module.

    Both the K12 and VRX have internal limiting that was designed specifically for each box by engineers that know more than you and me combined. "Fixing" the limit settings is not necessary.
    ksmalk08 wrote:
    How would a Driverack 260 compare GENERALLY/OVERALL to a BSS Minidrive FDS-334T if the number of ins/outs isn't critical? I know they are both Harman brands so maybe you can speak to them. (Should I start another thread for this maybe?)

    A BSS Minidrive FDS-334 is a better sounding unit than a DR260 (and more expensive as well) but you will soon out grow only 4 output channels and kick yourself for not getting a FDS-336. As I remember, the Minidrive is a little light on features as well. If my only choices were 334 or 260, I think I would choose 260 for the additional two outputs.

    Dennis
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