Sub wiring to 4ohms, how to figure correct RMS

kenstewart
kenstewart Posts: 139
edited March 2006 in Car Subwoofer Talk
I have an Image Dynamics dual-voice coil 2 ohm sub on the way that I plan on wiring to 4 ohm. Can someone explain how to figure RMS from going 2 ohms to 4 ohms? Specs in the manual just say 50-300 RMS and 1 to 4 ohms depending on config.

Guess I should caveate that I'm running Polk DB570s in my doors for help :) The new sub is an Image Dynamics ID8 D2 v.3. My amp is 200x1 @ 4 ohms ... any ideas on what I should expect for powerload? Sorry If I'm not being clear enough, I'm a little puzzled myself.
Eclipse CD8445 HU
Image Dynamics CXS54 Chameleons component setup
Two 8" Image Dynamics ID8D2v.3 subs
MTX MXA6001 amp for subs
MTX MXA3002 2-channel amp for comps
Accumat and Peel-n-Seal
Stinger and Knukoncpetz wiring
Post edited by kenstewart on
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Comments

  • CrBoy
    CrBoy Posts: 580
    edited March 2006
    The amount of power the sub can take is the same regardless the wiring (in this case up to 300RMS), the only difference is the load presented to the amp... You need an amp capable of producing 300wrms x1 at 4 ohms (or 300RMS at 1 ohm)... You can use your amp (200rms x 1) but the sub will not perform at it best due to underpowering...

    Hope this helps! :)
    <|>
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  • MacLeod
    MacLeod Posts: 14,358
    edited March 2006
    CrBoy is right. Ohm rating has nothing to do with how much a speaker can handle. It simply shows the load that it will present to an amp. Remember, the speaker is the load.

    Now an amp will have different power outputs depending on load impedance. Take the Polk 500.1, it will make 350 watts at 4 ohms and 500 at 2.
    polkaudio sound quality competitor since 2005
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    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D
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  • kenstewart
    kenstewart Posts: 139
    edited March 2006
    Thank you for the very simple answers, just what I needed :)
    Eclipse CD8445 HU
    Image Dynamics CXS54 Chameleons component setup
    Two 8" Image Dynamics ID8D2v.3 subs
    MTX MXA6001 amp for subs
    MTX MXA3002 2-channel amp for comps
    Accumat and Peel-n-Seal
    Stinger and Knukoncpetz wiring
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  • CrBoy
    CrBoy Posts: 580
    edited March 2006
    youre welcome buddy!!! ;)
    <|>
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  • Toxis
    Toxis Posts: 5,116
    edited March 2006
    Personally, I don't think 200w on a 300w sub is underpowering it. I mean we're talking about an 8" driver here. But it all depends on how much output you're wanting from it. Gotta keep in mind you're running an audiobling amp who's not exactly a clean amp (unless distorted sounds good to you) so you can't get crazy with the volume/gains.
    Never kick a fresh **** on a hot day.

    Home Setup: Sony VPL-VW85 Projo, 92" Stewart Firehawk, Pioneer Elite SC-65, PS3, RTi12 fronts, CSi5, FXi6 rears, RTi6 surround backs, RTi4 height, MFW-15 Subwoofer.

    Car Setup: OEM Radio, RF 360.2v2, Polk SR6500 quad amped off 4 Xtant 1.1 100w mono amps, Xtant 6.1 to run an eD 13av.2, all Stinger wiring and Raammat deadener.
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  • CrBoy
    CrBoy Posts: 580
    edited March 2006
    you're right Toxis but in his case I think it will be better to get the 300 rms amp to be able to keep the gain low and have the best possible SQ, instead of trying to get a lot from a cheap (don't really know) 200w amp that would be clipping like hell and will toast the lil sub with a clipped signal...

    Anyway he has 2 subs now, and he's looking at MTX amps so he should be fine whatsoever...
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  • kenstewart
    kenstewart Posts: 139
    edited March 2006
    Yep, thanks to the help I got here I've determined my final setup ... sorry Polksters, but I'm putting the Polks into my son's car when he gets it, they've been great speakers but I've moved on to Image Dynamics.

    Eclipse CD-8445 (on it's way this week)
    Image Dynamics ID8 D2 v.3 subs (2 each)
    Image Dynamics CTX6S for front (will check these out before going to components)
    Still keeping Polk DB570s for now in the rear (faded out until I have rear passengers)
    MTX Thunder 684 amp for coaxes
    MTX MXA6001 amp for subs

    Gonna make my own enclosures and amp racks to place behind the seats in my Explorer Sport Trac.
    Eclipse CD8445 HU
    Image Dynamics CXS54 Chameleons component setup
    Two 8" Image Dynamics ID8D2v.3 subs
    MTX MXA6001 amp for subs
    MTX MXA3002 2-channel amp for comps
    Accumat and Peel-n-Seal
    Stinger and Knukoncpetz wiring
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  • Toxis
    Toxis Posts: 5,116
    edited March 2006
    not a bad choice. I'm a huge fan of ID for their sound and their build quality. No harm on this side of the 'Net.
    Never kick a fresh **** on a hot day.

    Home Setup: Sony VPL-VW85 Projo, 92" Stewart Firehawk, Pioneer Elite SC-65, PS3, RTi12 fronts, CSi5, FXi6 rears, RTi6 surround backs, RTi4 height, MFW-15 Subwoofer.

    Car Setup: OEM Radio, RF 360.2v2, Polk SR6500 quad amped off 4 Xtant 1.1 100w mono amps, Xtant 6.1 to run an eD 13av.2, all Stinger wiring and Raammat deadener.
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  • kenstewart
    kenstewart Posts: 139
    edited March 2006
    Thanks Toxis ... something I just realized though, my new HU says it puts out 8v on the preouts ... the MTX amps take up to 5v, will this be a problem? Or are the 8v only when the HU is cranking full bore?

    Maybe new thread is more appropo ...
    Eclipse CD8445 HU
    Image Dynamics CXS54 Chameleons component setup
    Two 8" Image Dynamics ID8D2v.3 subs
    MTX MXA6001 amp for subs
    MTX MXA3002 2-channel amp for comps
    Accumat and Peel-n-Seal
    Stinger and Knukoncpetz wiring
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  • neomagus00
    neomagus00 Posts: 3,899
    edited March 2006
    8v is at full bore... the fact that the amp only takes 5V means you'll have to tune with your maximum volume at like 65% of the HU's max, instead of the standard 75%-90%
    It's not good, very fundamentally simply not good. - geolemon

    "Its not good enough until we have real-time fearmongering. I want my fear mongered as it happens." - Shizelbs
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  • kenstewart
    kenstewart Posts: 139
    edited March 2006
    Ahhhh, I see ... thanks :)
    Eclipse CD8445 HU
    Image Dynamics CXS54 Chameleons component setup
    Two 8" Image Dynamics ID8D2v.3 subs
    MTX MXA6001 amp for subs
    MTX MXA3002 2-channel amp for comps
    Accumat and Peel-n-Seal
    Stinger and Knukoncpetz wiring
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