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Old 04-16-2007, 12:40 PM   #1
rxer311
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Default what will my impedence be?

So I am looking for the answer to this question. I am looking to get a 4 channel amp to power my front speakers and my subwoofer. I have a dual voice coil 4 ohm subwoofer. If I wire this in paralell and bridge it off 2 of the channels is that running at 2 ohms? If I wire it in series is that running at 8 ohms? I am wanting to run it in paralell off of the 2 channels and have it run at 2 ohms. I know off of a mono block sub this runs at 2 ohms but was not sure if it is the same running off of 2 bridged channels...

Thanks in advance!
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Old 04-16-2007, 12:41 PM   #2
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yep, it's the same....
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Old 04-16-2007, 12:49 PM   #3
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So now I just need to find a 4 channel amp that is stable bridged at 2 ohms...
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Old 04-16-2007, 12:51 PM   #4
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yep, most "should" be...but not all, depends on what your looking at...
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Old 04-16-2007, 12:51 PM   #5
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I'm running a Kicker KX600.4 running as you have described. Runs great. Contact S/N: RossWRX he'll hook ya up for a smokin deal. He can also answer all you questions and then some.
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Old 04-16-2007, 12:53 PM   #6
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I am running a phoenix gold 250 watt RMS sub. Thinking about a kenwood excelon or similar.
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Old 04-16-2007, 12:59 PM   #7
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Just browsing around it doesn't look like there are many amps stable bridged at 2 ohms...
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Old 04-16-2007, 01:15 PM   #8
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Quote:
Originally Posted by rxer311 View Post
Just browsing around it doesn't look like there are many amps stable bridged at 2 ohms...
Most of the ones that are 2 ohm stable are going to cost some $$$. Most amps are only 4 ohm stable when bridged. You'll need to look at the PG Xenon series, JL Slash series, and some of the more high end amps out there.
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Old 04-16-2007, 01:21 PM   #9
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Quote:
Originally Posted by rxer311 View Post
Just browsing around it doesn't look like there are many amps stable bridged at 2 ohms...
Seriously.... man, i though MOST were 2ohm stable bridged.... What price range are you looking at??


I'll give you my advise..... Ebay....
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Old 04-16-2007, 01:24 PM   #10
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I am looking on ebay. I was looking at a soundstream, ma audio, etc
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Old 04-16-2007, 01:25 PM   #11
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Here is another question then...could I run 2 channels for the front and just use 1 channel for the rear? But then it would be playing in stereo and the bass would only be half playing right?
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Old 04-16-2007, 01:34 PM   #12
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And even another question...if an amp is putting out 240 watts bridged at 4 ohms what would it be putting out at 8 ohms? I have a 250 watt rms sub and want it to be close...
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Old 04-16-2007, 02:28 PM   #13
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Well, at 8ohms, you "halve" the output power....


Say 250w @4ohms

125w @8ohms

But ~500w @2ohms...

This doesn't ALWAYS hold true, but is a retelatively good "rule of thumb" in 12v audio....

I don't know if you have seen me post this graph i'm about to post before, but if not, it's the Ohms Laws "wheel" and if you can understand it, it's the "Holy Grail" of the electrical world.... search on it, learn about it, feel your knowledge grow...
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Old 04-16-2007, 02:35 PM   #14
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Thanks!
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Old 04-16-2007, 02:38 PM   #15
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No problem, i hope it helps and doesn't confuse...
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Old 04-16-2007, 02:40 PM   #16
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I'd check the specs. Some amplifiers reduce output voltage when driving a small impedance load. This causes the output to be much lower than expect. I run a 10" 4Ohm DVC on two 50W channels, un bridged and set to mixed mono. Plenty loud, this obsession with 2ohm and 1ohm stable amplifiers is really beyond justification.

Last edited by LastResort; 04-16-2007 at 03:30 PM.
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Old 04-16-2007, 03:02 PM   #17
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I Agree With Last Resort On His Comment. I Would Try Running The Amplifier At 2ohm Mono...the Worst That Could Happen Is The Amp Will Get Too Hot And Send Itself Into Protection Mode....should This Happen, Just Change It To 4ohm Stereo, But Be Sure If You Run It In Stereo That You Use A Y-adapter On Your Rca Cable So That You Dont Mix The Signals On A Dvc Sub. So Long As You Dont Bury The Amp In Your Trunk Or Under A Seat...give It Good Ventilation, It Should Work Pretty Well. Start With The Gain/sensitivity Low And Work Your Way Up To The Listening Level You Want. You're Not Going To Be Able To Pound It Very Hard. One More Thing....make Sure You Have A Very Good Ground And That Your Power Wire Is Adequate And fused.
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Old 04-16-2007, 03:29 PM   #18
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I always bought Rockford Fosgate amp and I was never disappointed, I own 3 Rockford amp, and four speakers
I looked the specs on their official website then search on ebay
Anyway, if you give us the spec of your speakers and subwoofer, I'm pretty sure we can advice you which amp you should buy.
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Old 04-16-2007, 03:40 PM   #19
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Quote:
Originally Posted by elladamerie View Post
Anyway, if you give us the spec of your speakers and subwoofer, I'm pretty sure we can advice you which amp you should buy.
I have a hodgepodge of a "system". I have JL tr 6.5 components up front (4 ohm 10-75 watts rms). I have ma audio 5.25" in the rear (4 ohm 60 rms). I have a phoenix gold octane 12 " sub (4 ohm dvc 250watts rms 500 peak). I am also thinking 5 channel amp for everything!
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Old 04-16-2007, 03:56 PM   #20
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Why don't you just run two amps? Or if it must be one amp, look for something that is class D for the subwoofer, and that will usually run 2 ohms.
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Old 04-16-2007, 04:11 PM   #21
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5 channel amps are costy, Rockford has one it's called Power 1000, It can give enough power for your speakers, but it will be too much for your sub.

I suggest you buy a rockford P450.4 for your speakers.
and a rockford P300-1 for your sub. You will wire your sub to have 2 ohm load
It had 50w more than your sub, so I suggest you don't much your gain like crazy or you might have some problem.
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Old 04-16-2007, 04:48 PM   #22
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Quote:
Originally Posted by Aaron'z 2.5RS View Post
Seriously.... man, i though MOST were 2ohm stable bridged.... What price range are you looking at??


I'll give you my advise..... Ebay....
Most are 2 ohm stereo stable. Since each channel only sees half the impedence when bridged, that makes them only 4 ohm mono stable.
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Old 04-16-2007, 04:48 PM   #23
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Gain has almost nothing to do with watts.
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Old 04-16-2007, 06:56 PM   #24
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I got this amp from another auction for $140 shipped. He was a private seller who bought the amp and never hooked it up. Still in the plastic in the box. I think I got a good deal. What do you think?

http://cgi.ebay.com/SOUNDSTREAM-5-CH...QQcmdZViewItem
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Old 04-16-2007, 10:06 PM   #25
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What does anybody think about that?
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