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PostPosted: Sun Mar 23, 2008 8:04 pm 
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I was wondering how I can get 2 8 ohm speakers to run at 4 ohms out of a 2 channel amp? I want to be able to push more power to the 2 speakers. Right now they run at 8 ohms stereo. So I was thinking that if I ran 1 connection from the amp to the first speaker, then plugged the second speaker into the first, then pressed the bridge mode on the amp? Will this bring the load to 4 or will it be 2 by the time I am done? Thank you very much!


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PostPosted: Sun Mar 23, 2008 11:42 pm 
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ohm's law

2 - 8 ohm speakers = 4 ohms

That being said if you have a 1500 watt amp in bridge mono at 4 ohms operation each speaker will get 750 watts

Where the same amp in stereo 8 ohm operation would be feeding the speakers around 350 watts.

I seed my 8 ohm subs about 1800 watts a piece.


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PostPosted: Mon Mar 24, 2008 1:11 am 
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Blackrose @ Sun Mar 23, 2008 8:04 pm wrote:
I was wondering how I can get 2 8 ohm speakers to run at 4 ohms out of a 2 channel amp? I want to be able to push more power to the 2 speakers. Right now they run at 8 ohms stereo. So I was thinking that if I ran 1 connection from the amp to the first speaker, then plugged the second speaker into the first, then pressed the bridge mode on the amp? Will this bring the load to 4 or will it be 2 by the time I am done? Thank you very much!


There is more to it than just connecting 2 8 ohm speakers in parallel.  Yes doing so will yield a 4 ohm load, however, can your amp handle a 4 ohm bridge?  What subs (make/model) & amp (make/model) do you have.  SOME amps cannot handle a 4 ohm bridge plus you got to make sure you are not going to be over drivng or underpowering your subs doing so (if 1 speakers program rating is say 500 watts at 8 ohms, connceting 2 8 ohm speakers in parallel (making a 4 ohms load) will need 1000 watts from your amp at 4 ohms to drive both).  Some amps can produce a considerably more amount of power in a bridged mode than a standard stereo mode.
Also if I were to bridge 2 speakers together I would run both speakers from the amp individually piggybacked with the same length cable going to each, not in a series run like you describe - it will work, but not the correct method.

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PostPosted: Mon Mar 24, 2008 12:02 pm 
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I have 2 pv18 subs, and a pv900 amp.


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PostPosted: Mon Mar 24, 2008 12:59 pm 
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Your amp is no where near capable of properly powering those 2 subs.

I suggest if you are looking to keep the price down a Carvin HD1800 would do the trick $330

If you would like a lighter amp a QSC 1802 would be my pick. Abot $650


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PostPosted: Mon Mar 24, 2008 1:47 pm 
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Blackrose @ Mon Mar 24, 2008 12:02 pm wrote:
I have 2 pv18 subs, and a pv900 amp.
I am assuming you mean the model PV118 (not pv18).  If this is the model, then each speaker at 8 ohms would require 400 watts to match their program rating (the rating you want to match the amp to the speaker).  Your amp in stereo mode is grossly underpowering them at 180 watts per channel at 8 ohms.  

Now the saving grace that will alleviate you from needing to buy another amp is the 4 ohm 'bridged' rating of the amp is 900 watts.  When you piggyback both 8 ohm speaker, it becomes a 4 ohm load.  Being that they are 400 watts @ 8 ohms singlely, when hooked together their 4 ohm power rating will be 800 watts.  Your amp pushes 900 watts bridged into 4 ohms so you should be fine.

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PostPosted: Mon Mar 24, 2008 3:37 pm 
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Thank you Lonman! When I bought them, the guy at Larrys Music told me that this amp would be a good match because it has a built in crossover, but I would have to bridge it. So in order for me to do this, I will have to run 1 speakon to one speaker, then out of that speaker, I would have to run a 1/4" into the next speaker right?

amp/bridged=========speaker===========speaker

Like this? Thanks again!


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PostPosted: Mon Mar 24, 2008 4:28 pm 
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The true watts of power from an amplifer to speaker ratio should be 2.5x in the use of subwoofers. I also reccomend a 40hz cut to save on wasted power.

Meaning if a speaker is 400 watts to properly power it one should provide the speaker with 1000 watts.

My subs are 600 watts I provide them with 1300 watts normally and i feel they are slightly underpoweerd.


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PostPosted: Mon Mar 24, 2008 5:35 pm 
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Blackrose @ Mon Mar 24, 2008 3:37 pm wrote:
Thank you Lonman! When I bought them, the guy at Larrys Music told me that this amp would be a good match because it has a built in crossover, but I would have to bridge it. So in order for me to do this, I will have to run 1 speakon to one speaker, then out of that speaker, I would have to run a 1/4" into the next speaker right?

amp/bridged=========speaker===========speaker

Like this? Thanks again!
Yes this amp will be fine provided you are running both speakers & in bridge mode.

Again, that configuration will work, but not recommended.  You should run both speakers back to the amp individually.  But since you can't split a speakon (or at least I have never seen a y-connector with Speakon ends) then this may be your only option.  Or you could just use the banana posts with a speakon end & piggy back the banana posts.

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0209117725

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