Is Bridging channels like series

ok there has been some confusion setup in my head from some post. if you lets say have a 2 ohm dvc sub and you series it gettting 4 and you bridge an amp would that be like series'esin :-/  the circuit again to 8ohms or would it drop it to 2 ohms or would it still be 4 ohms. Also if an amp shows a setup that is 2 ohms at a certain rms does it mean it can do 2 ohms stable? how would you know what it can do stable if it doesn't show? and how about if I have a amp that does 500 rms to a mono output and put 2 subs on it they would be getting 250rms each right? arg...

that throwing idea sounds like fun :-)  I was asking it in a wierd way but what I ment is if it just said  XXXrms @ 4 ohms  and nothing about 2 ohms it wouldn't be stable?

and what if I had a sub that was 250 rms and one that was 350 rms what would happen?

[QUOTE=aznboi3644]

If the amp or manufacturer doesn't state what the amp is stable down to than it sucks balls and should be thrown at a mailbox while standing out of a sunroof in a friends toyota camry going 60 down a country road. [QUOTE=aznboi3644]

hmmmmmmmm......? good knowledge to know.

aznboi3644 wrote:

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Um...if you bridge an amp at 4 ohms its really seeing 2 ohms 

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I have heard this before, and have yet to have someone explain the logic of it to me.  If the nominal impedance is truely 4 ohms, then there is no way the impedance will drop lower than that at the amplifier no matter how it's wired.  It will see the load presented to it.  Would you claim that of the dozen doughnuts sitting in front of you, that you can only see six with one eye closed?

Or are you talking about the load an amplifier can handle bridged compared to stereo?  If an amplifier can handle a 2 ohm load in stereo, it can only handle a 4 ohm load bridged.  But that doesn't effect the load it sees.

Steven Kephart wrote:

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aznboi3644 wrote:

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Um...if you bridge an amp at 4 ohms its really seeing 2 ohms

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I have heard this before, and have yet to have someone explain the logic of it to me. If the nominal impedance is truely 4 ohms, then there is no way the impedance will drop lower than that at the amplifier no matter how it's wired. It will see the load presented to it. Would you claim that of the dozen doughnuts sitting in front of you, that you can only see six with one eye closed?

Or are you talking about the load an amplifier can handle bridged compared to stereo? If an amplifier can handle a 2 ohm load in stereo, it can only handle a 4 ohm load bridged. But that doesn't effect the load it sees.

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Steven really described it best.

The problem is most people don't understand that when they have a "2ohm stable" stereo amp..this is the rating for stereo..not bridged mono. So this rating means you can connect 2-2ohm loads in stereo to it...or a 4ohm load bridged to it..really not that complicated.

Now with a mono block amp the rating is not stereo..a mono amo can never be stereo..so if it is one ohm stable..you can hook a one ohm load to it.  The rule of thumb is you will loose up to half the power has you double the ohms..but you can never go below the ohms rating of the amp or it will go into protection..overheat...basically be a mess until something gives.

now with voice coil wiring it is tricky for some people to grasp the concept so I will attempt to simplify.

Simply put..no matter how many voice coils a speaker has..you need to think of it has just one speaker..where by how we decide to wire the coils (series or parallel) will determine its final load.  The amp does not see each coil individually..it sees the final load only.  basic ohms law...if you series the voice coils..you add them together to get the final load. If you parallel them..since they are the same value each coil..you just divide.

Then regardless of svc..or dvc..or how many subs...you need to make sure when you wire them to the amp..weather series or parallel..mono or stereo...that we do not present a load to the amp that is below it's rating. Having multiple DVC subs, and stereo amps that can be ran stereo or bridged..gives us plenty of flexibility for wiring configurations to get the most out of the amp/sub setup without destroying anything.

That about sums the simplification.

Exactly.  The combination of the subs quantity and wiring of voice coils just presents a final effective resistatance to the amp.  An amp still sees 4ohms NOT 2 ohms when bridged as steven described

mike12volt, there is nuthing wrong with bridging front speakers, its just not as common as bridging for a subwoffer.  Depening on the distortion rating on the amps and the impedance of the front speakers, and the quality of SQ required will tell if its sutiable to bridge the fronts

That is true mike 12volt...I notice that you need to check the specs on each specific amp..so even though the "rule of thumb" is most common..it is not always the case when dealing with power output.

But again, where I see alot of people misunderstanding is when they have a 2 channel amp that states it is "2 ohm stable". They attempt to run 2 -4ohm subs bridged to it thinking this is fine.  But where they messed up is that they didn't read into the specs carefully enough to see that this "2 ohm stable" rating is a STEREO rating.

In this case if using 2 subs they need to be a minimum of 8 ohms each if bridging it. I can't tell you how many customers I have that come in with amp problems due to this. To correct the problem (usually it is cutting out after a length of time) I have to either run the amp stereo and have a potential power output decrease (not always a major issue) or convince them to purchase 2 -8 ohms subs or a different amp (2ohm min stable mono or 1 ohm stable stereo).