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Thread: Two amps to one sub???

  1. #11
    Raw Wave Rob Withey's Avatar
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    Quote Originally Posted by Shadow View Post
    That's called strapping. Not all amps can do that.
    Ok, so the specific amps in discussion can't do that? That's a good reason.
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  2. #12
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    Scott, I found out what Alma had. They're called phase shifters and they were custom made 50 channel phase alignment processors. I don't know who made them but I can guarantee they weren't cheap especially considering that truck had over 4 miles of Kimber Select cable in it

  3. #13
    Low Bitrate frugmonkey's Avatar
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    just looking at all the options really, i'm not quite sure which way to go with getting amps to power my subs, i can go for either two amps that will drive at one ohm and have them running one per sub. or a single one that will run the pair at two ohms
    not been having much luck with my current sub amp, its been repaired by the manufacturer three times and hasnt really worked for more than an hour, and then every time you send it back it takes them FOUR MONTHS to not fix it properly!

    so can anyone recommend a good amp (or amps) that will run either 1200-2500 RMS at one ohm, or a single that will do 2400ish to 5000 RMS at two ohms?
    ive heard good things about the hifonics colossus, but they are very hard to come by in england, as it would seem most stuff like that is.
    about the best option ive seen so far over here is the new model Directed 2400D, thats 1200rms at one ohm, but i'm not sure from past experience whether to use their stuff again, and they look a bit on the kids toys side of things, what with all the glowy lighty up bits, i hate flashy lights on stuff like that!
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  4. #14
    Maximum Bitrate bes51659's Avatar
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    Oops, we are talking real power here... I guess you must be knowing what you are doing but anyway:

    Whatever way you turn, your speaker can handle 2000W RMS. You only got the choice of 2x1000W in 2ohm or 1x2000W in 1 or 4 ohms.

    The hifonics can drive 1x2000W in 4 ohm which directly translates to 2x1000w in 2 ohm. (bridge coupling) (I get suspicious when they spec 2x1100W..). All RMS if you beleive their spec. When you are using a bridge I would prefer the coils in serial rather than separate, but the difference is neglectable.

    Forget about the coils in parallell to get one ohm, even if you can get a cheaper amp that states 2000W in 1 ohm. For reasons already mentioned which are even more valid with a Class D amp with passive filters at output.

    Sorry no experience in amps in that segment :-) I have a DLS A5 myself.

    Good luck.

  5. #15
    FLAC
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    Memphis 4KW AKA Mojo will do 400WRMS

    When you are using a bridge I would prefer the coils in serial rather than separate, but the difference is neglectable.
    Wrong, the wiring definitely makes a difference. Also, if he's wiring in parallel to get 1 ohm then series would give him 4 ohms. It's going to be TONS easier to get that power at 1 ohm than 4 ohms.

  6. #16
    Maximum Bitrate bes51659's Avatar
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    If you compare 2x1000W in 2x2ohm with 1x1000W in 1x4 ohm the differens is very small if any at all. That is serial compared with _separate_.

    Now, if you compare parallell with serial, that is 1 ohm compared with 4 oms there is a great differens, and I prefer 4 ohms if you can afford the amplifier.

    In 1 ohm the current is two times higher in all speaker leads, loss is four times higher, and you will get 6dB less damp factor. (More rumble than kick)

    But maybe you will be outside the car anyway :-) (Sorry, I couldn't resist. I do like to crank it up too)

  7. #17
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    Quote Originally Posted by bes51659 View Post
    If you compare 2x1000W in 2x2ohm with 1x1000W in 1x4 ohm the differens is very small if any at all. That is serial compared with _separate_.

    Now, if you compare parallell with serial, that is 1 ohm compared with 4 oms there is a great differens, and I prefer 4 ohms if you can afford the amplifier.

    In 1 ohm the current is two times higher in all speaker leads, loss is four times higher, and you will get 6dB less damp factor. (More rumble than kick)

    But maybe you will be outside the car anyway :-) (Sorry, I couldn't resist. I do like to crank it up too)
    Huh?

    2x1000w > 1x1000. Regardless of impedence.

    I debate if you can hear the difference in dampening factor especially when its impact is correlated directly to its enclosure. Its splitting hairs when pople at this stage are only after sheer volume anyways.

    The loss of efficiency is a concern and I would normally recommend running any stereo amplifier in stereo mode (but with a mono signal) at its nominal impedence unless you compensate for current draw in power flow and alternator. low impedence = high current. I find little value in low impedence amplifiers unless people are limited on physical space.

    I do not like to run any speakers in series if it can be avoided. Its adding an unintentional crossover network into the mix. Yup, the cutoff frequency may be higher that the speaker can reproduce but it can be easily eliminated with proper component selection.

    I recommend a strong 2x250w RMS (@4 ohm) amplifier if the OP is dealing with a 2 ohm DVC sub. Run it in stereo at 2 ohms and plan on a little less than 500 watts rms to the subs. Hell even half of those specs would be louder than necessary.

  8. #18
    FLAC
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    I find little value in low impedence amplifiers unless people are limited on physical space.
    1000W class D that does its power at 2 ohms is going to be cheaper and more efficient for subwoofer use than a class A/B amp that does all of its power at 4 ohms.

    Good point about the series wiring introducing a passive crossover.

    Bad idea recommending that someone run a subwoofer in stereo even if you did mention mono signal. Most people just starting out won't understand what that is or how to do it.

  9. #19
    FLAC XC-C30's Avatar
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    Quote Originally Posted by scott_fx View Post
    curious...what is this piece of hardware?
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  10. #20
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    Quote Originally Posted by bes51659 View Post
    With two voice coils you get all kind of possibilities.

    You can connect them in parallell to get low impedance and high power output from one amp, or you can connect them in series to get 4 times that impedans and that much better damp factor. (better bass definition)

    Or you can use a stereo amplifier as suggested.
    incorrect

    parallel = a*b/(a+b) so 2 fours gets you 2, etc
    series = a+b so 2 fours gets you 8...
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