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Thread: What size amp do I need to power these subs?

  1. #1
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    What size amp do I need to power these subs?

    I have 2 10" Boston Aucustics G5's subwoofers. I replaced my 2 x12" Fosgate subs which were running off a P6001RD (which i still think wasnt enough). The BA's sound like **** on this, and I think I am way under powered here.

    What do I need to look in for an AMP to power 2 of these 10" G5's?

    Specs on the BA website, but I see this on the sheet.

    1 G5 = RMS POwer Handling 450w / DUal 4ohm, Tuning freq 34hz

  2. #2
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    car audio section?

    lets see... 450w rms x 2 = 900 rms (at least).

    underpowering subs will not cause them to sound like s**t. high gains (clipping) will as well as a bad install (incorrect box size).

  3. #3
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    Well, its not that they sound like ****, its that they are not loud, not much bass at all.

    How do I tune the high gain clipping? I'm a noob in the actual sub/amp stuff, not PC stuff though.

    Free free to move the thread, I missed the car audio section, sorry

  4. #4
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    Would any of these amps be enough? Most have 1000+RMS but only at 1x2ohm I think.

    http://www.bestbuy.com/site/olspage....=1198888991131

    http://www.bestbuy.com/site/olspage....=1199494646259

  5. #5
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    wanna try that amp model number again? i can't find anything on it (brand/model number). you may be able to wire it down to 1 ohm to get more power but i need the amp info.

    my other recommendation would be to get out of best buy. there a slew of internet companies producing higher quality goods at lower prices. you can also get almost anything cheaper in other online stores (although i will not recommend anything that is an unauthorized sale).

    lets take it 1 step at a time though. amp specs?

  6. #6
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    I only said best buy cause I'm really wanting to get my setup 100% for today....but here goes

    My current Sub AMP for the 2x12" Punch subs I was running is a :

    Rockford Fosgate P6001BD (sorry had typo above, not 1RD its 1BD). Its the one with the metal sides, this is the exact one I have, http://cgi.ebay.com/NEW-Rockford-Fos...QQcmdZViewItem

    Here it is physically installed in my car, on the right of this picture:



    Here is a picture of the new box installed with the G5's:


  7. #7
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    ok heres some issues:

    1) because you have 2 dual 4 subs you can't wire to 2 ohms... meaning you are probably running at 4 (300w).

    2) that amp is not 1 ohm stable so you won't get the power you need out of it.

    3) hopefully the box is within specs.

    so if you really must go to best buy and make it happen today i would say the alpine MRP-M1000, but if you have any local mom & pop stereo shops i would start there. theres much better equipment out there.

    what you need:
    1000w rms @ 1 ohm

  8. #8
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    Kurak, there are still some questions we need answered before we can give you an accurate answer. You may not need a new amp. First of all, those subs are available both in single 4 ohm AND dual 4 ohm, which do you have? If you have dual 4 (two terminal connections on each sub), it's correct that you can't wire down to a 2 ohm final load. HOWEVER if you have the single 4 ohm version (only one set of terminals on each sub) you CAN wire to a 2 ohm load and get twice as much power.

    Also, what you're describing sounds more like a wiring issue than an amp issue. Clipping would most likely cause your amp to go into protection mode and shut down so I don't think that's the problem. If you have accidentally reversed the polarity (even the pros do it...accidentally connected the negative to the positive and vice versa) your subs will sound VERY quiet. Doesn't matter if you throw 3000 watts at them, if the polarity is wrong they will sound like they're almost off no matter how much you adjust the gain/volume/EQ settings.

    I would check your wiring, make sure it's all correct. Also, let us know whether you have the dual 4 ohm or single 4 ohm subs because you may be able to get the load you want by just changing the wiring. If all this fails, I will resort to saying Rockford amps suck balls...which I will actually say anyway. You should not be powering those subs w/ a garbage amp from best buy. Not trying to insult you, just saying the subs will sound and perform MUCH better with a high quality amp on them

  9. #9
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    The choice of subs is going to make it hard to get high SPL. They have a 1w/1m sensitivity of 85dB. Having two of these, both at redlining at 450 watts, under perfect conditions (i.e. a sine wave generator) you will still only have a maximum possible SPL of ~108dB SPL at listening distance. If you were to shove your face 1 foot away, you would get ~125dB, but that's not a usable measurement since you don't drive in your trunk

    Real world, I wouldn't expect you to be able to reach a continuous output over ~105dB SPL. Better subs (read: more efficient) would go a long way to creating higher levels, and would be a more worthwhile expenditure of your money IMHO.

    Also, the difference between a 450w / channel amp and the RF amp you have linked to above will only be a maximum change of 1.5dB SPL/chan, so a total of about 3dB SPL. And again, that's if you were actually running at redline. Which you aren't, and very rarely will. Is 3dB SPL really worth the money to you?


    Just an example, if you got a set of subs with a 1w/1m sens. rating of 90dB SPL, the same 450 watts/channel would give you ~113dB. If you got a high efficiency set that were rated around 95 dB SPL @ 1w/1m then that same 450 watts/channel would give you 118dB.

    In contrast, to make your subs (theoretically, if it didn't exceed their power handling/cooling ability) that same 118dB SPL at listening distance would require you to have an amp that was 4500 watts per channel!!!

    I should also note that these numbers are all in perfect conditions. They're based off numbers measured in an anechoic chamber. ALL real world numbers will be lower because of material absorption, and other obstacles between you and the speakers.

  10. #10
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    Ok so the G5's I got have only 1 set of terminals on them , BUT, the box/model that I have says "Boston G5 10, Dual 4ohm Voice Coil.

    I checked my wiring, I got from each of the negative on my sub amp to each of the negative on the subs, same for positive. THe subs just done thump hard...barely noticable <hmmm>.

    All I want is nice thump, nothing award winning....these subs should do it. I think this amp might have issues also...never seemed to get real thump using it...but my last 2x12"'s thumped decently with it though.

    I will post pictures of the subs closer

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