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  1. #1
    Join Date
    Oct 2009
    Posts
    100

    Default ???'s on my HLCDs & amp tower set up

    1st of all I was told I would be fine running these speakers @ 2ohm, which if im figuring correctly will yeild me 215 watts @ each of the 4 speakers. However I was also told that it is possible that my speakers could be dropping the load to under 2 ohm which is not good for the amp. I am assuming it is necessary to run my set up @ 2ohms to get enough power to push the speakers to their potential. If its not gonna yield much more audible power I guess I will wire them back to 4 ohms to save possible wear on the amp. Any advice?

    This is the descriptions of my amp/speaker setup.


    Kicker ZX850.2
    ZX Series 2-Channel Class AB Car Amplifier
    RMS Power Rating:
    4 ohms: 295 watts x 2 chan.
    2 ohms: 425 watts x 2 chan.
    Bridged, 4 ohms: 850 watts x 1 chan.
    Max power output: 850 watts x 2 chan.



    Krypt 8" HLCD (4 of these speakers)
    Nominal Diameter 8 inch
    Nominal Impedance 4 ohm
    RMS Power 180 Watts
    Peak Power 360 Watts
    Sensitivity (1w/1m) 93 dB
    Frequency range 60 - 20K Hz

  2. #2
    Join Date
    Jul 2008
    Location
    Des Moines, IA
    Posts
    2,614

    Default

    Nominal impedance on those speakers is 2 ohm, so IMO you're working within the established limits of your gear. Crank it.

  3. #3
    Join Date
    May 2009
    Location
    Dallas, TX
    Posts
    880

    Default

    I believe those Krypt midbass drivers have a DCR just around 4-ohms. But because they may use a passive highpass filter only and without a symmetrical lowpass filter the impedance could potentially dip down to 3-ohms in the midrange region. Two speakers in parallel per channel could represent a 1.5-ohm load which may cause real thermal stability issues with some amplifiers.

    David
    Earmark Marine

  4. #4
    Join Date
    Jul 2008
    Location
    Des Moines, IA
    Posts
    2,614

    Default

    Quote Originally Posted by EarmarkMarine View Post
    I believe those Krypt midbass drivers have a DCR just around 4-ohms. But because they may use a passive highpass filter only and without a symmetrical lowpass filter the impedance could potentially dip down to 3-ohms in the midrange region. Two speakers in parallel per channel could represent a 1.5-ohm load which may cause real thermal stability issues with some amplifiers.

    David
    Earmark Marine
    You clearly know best so I'm not challenging. But would those 1.5 ohm dips really present a problem for a 2 channel amp that is rated to run safely at 2 ohms? I only ask because I see installs all the time where people (unknowingly) are bridging a 4 channel to where it will see 1 ohm continuous. I'm not advocating that this is good practice, especially in a marine environment. It just makes me wonder if people get away with 1 ohm all the time if the occasional dip below 2 ohms is really a big deal. Thanks for any insight!

  5. #5
    Join Date
    Oct 2009
    Location
    Pacific NW USA
    Posts
    511

    Default

    Duece - whats the problem? is your amplifier shutting down? I see what you say you where told but whats the reality in the real world - i.e. installed and on the water?

    2 ohm loads are tough on many amplifiers. If this is the case, I have 1 suggestion for you

    HARPOON 500x2 @ 2 ohms.

    we build this amp for guys like you that need a beast. Ask Mandley if he's been amble to shut his down.

    Ask Earmark what his impression was when he received his.

    on the task of making the most of what you have, if the kicker is shutting down due to 1.5 ohm / thermal issues.... add in a nice quiet fan to the cubby area and it should help a lot. If there is no thermal issues... crank it!

    good luck!

    -Brian
    Exile

  6. #6
    Join Date
    Dec 2006
    Location
    Tigard, Oregon
    Posts
    3,016

    Default

    Quote Originally Posted by mk_deuce View Post
    1st of all I was told I would be fine running these speakers @ 2ohm, which if im figuring correctly will yeild me 215 watts @ each of the 4 speakers. However I was also told that it is possible that my speakers could be dropping the load to under 2 ohm which is not good for the amp. I am assuming it is necessary to run my set up @ 2ohms to get enough power to push the speakers to their potential. If its not gonna yield much more audible power I guess I will wire them back to 4 ohms to save possible wear on the amp. Any advice?

    This is the descriptions of my amp/speaker setup.


    Kicker ZX850.2
    ZX Series 2-Channel Class AB Car Amplifier
    RMS Power Rating:
    4 ohms: 295 watts x 2 chan.
    2 ohms: 425 watts x 2 chan.
    Bridged, 4 ohms: 850 watts x 1 chan.
    Max power output: 850 watts x 2 chan.



    Krypt 8" HLCD (4 of these speakers)
    Nominal Diameter 8 inch
    Nominal Impedance 4 ohm
    RMS Power 180 Watts
    Peak Power 360 Watts
    Sensitivity (1w/1m) 93 dB
    Frequency range 60 - 20K Hz
    Your amp is seeing a 2 ohm load because you have four speakers wired in parallel and being driven by 2 channels. There is no way to wire 4 four ohm speakers to a 2 channel amp and present a 4 ohm load to the amp. Like Brian said, if your amp is seeing something less than 2 ohms, it will get hot and may go into protect mode. If its not going into protect (shutting down), then you're golden.
    Al

    2006 Mobius LSV

  7. #7
    Join Date
    May 2009
    Location
    Dallas, TX
    Posts
    880

    Default

    Brian,
    I hear you but those multi-channel amplifiers loaded down to 1-ohm sound terrible even though their owners may not recognize it. So I don't go by what others may be doing. Often they run fewer channels because they're restrained by budget or they think they are cheating the laws of physics with inordinately low loads. Ohms Law doesn't apply when you have a limited supply resource (the DC to AC to DC switching power supply). When you hit that wall you clip and compress. Very few amplifiers are truely equipped to run lower than 2-ohm stereo loads or 4-ohm bridged loads without serious degradation or thermal issues. Heat changes performance. As the load is lowered distortion rises, damping falls, efficiency falls, voltage sags, etc. Most amplifiers are biased to operate optimumly at a particular load where performance suffers in one respect or another on either side of that peak. You're going to pay a real premium for those few amplifiers that maintain a consistent level of performance over a broad range of supply voltages and load impedances. But we all take a few liberties in boat stereos. The acid test is whether or not the amplifier shuts down on a 95 degree plus day. So in the above scenerio of the OP it should work and if it doesn't then you know why. A more comprehensive crossover design definitely can be friendlier to an amplifier. I believe Phil with Kicker could add to that.

    And yes the Exile amplifier has excess heat sink mass and twin power supplies to meet the demands of some tough conditions. Its very similar to having two monoblocks.

    David
    Earmark Marine

  8. #8
    Join Date
    Oct 2009
    Location
    Pacific NW USA
    Posts
    511

    Default

    Allgood points from good people. Honestly if the op has the amp on hand already I'd crank it up and put it to the test.

    In my experience, the 95 degree day usually brings with it a cubby temp of 115+ degrees on the skin of any given ampliifer. Ultimatley time under tension will tell. And if your amp does turn off that's a good thing because it's protecting itself.

    Let us know how it works out.

    Cheers!

    Brian
    Exile audio

  9. #9
    Join Date
    Oct 2009
    Location
    Pacific NW USA
    Posts
    511

    Default

    On second thought... I wantto start a thread titled,

    Show me how to cheat the laws of physics and the sum of all nodes is not zero!!'

    ---- passes the mic to Phil.

  10. #10
    Join Date
    Oct 2009
    Posts
    100

    Default

    Well I believe the amp was deffective from the start actually. I had the speakers wired @ 4 ohms & it acted funny a few times. i.e. one side went out, but never thermal. I wired it to 2 ohm and it ran great for about the 3 hrs then acted like it was over voltaged then went into protect mode but wouldnt come out of it. (again it never went to thermal) I had to send it in & Kicker warrantied it so when I get it back I want to make sure I dont wire the speakers as to make it unecessarily hard on the amp for no extra audible gain.






    Quote Originally Posted by Brianinpdx View Post
    Duece - whats the problem? is your amplifier shutting down? I see what you say you where told but whats the reality in the real world - i.e. installed and on the water?

    2 ohm loads are tough on many amplifiers. If this is the case, I have 1 suggestion for you

    HARPOON 500x2 @ 2 ohms.

    we build this amp for guys like you that need a beast. Ask Mandley if he's been amble to shut his down.

    Ask Earmark what his impression was when he received his.

    on the task of making the most of what you have, if the kicker is shutting down due to 1.5 ohm / thermal issues.... add in a nice quiet fan to the cubby area and it should help a lot. If there is no thermal issues... crank it!

    good luck!

    -Brian
    Exile

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