[vonnie123]

Greetings,

I am considering changing out my AV Receiver for an AV Processor and would lose two channels of amplification in the process.  What are the ramifications, if any, for doubling up pair of six ohm speakers (two pairs) instead of each pair having its dedicated amp power.  My understanding is the net impedance of two separate six ohm speakers (being used for surround channels) on a single amp channel, translates it to being a 3 ohm load.  I am using a Class D amp, and want to prevent potential amp damage.  Is this an issue....The amp channels are 250WPC, I listen at mostly low volume levels and I doubt it ever sees more 10 watts output.  Any thoughts on setting up this way?  Thank you.

[JRace]

It depends...

On the speakers and the amp.

To give a proper answer please provide the make and model of each.

Generally speaking most amps will handle a 3ohm load at low to moderate volume levels.

[srb]

It would be nice if most speaker loads were a constant resistance, but the impedance usually varies with frequency.  You might have an "8Ω nominal" speaker that has a minimum impedance of 3Ω at some frequencies.  That's why it's helpful for a speaker manufacturer to state the minimum impedance, and better yet, supply an impedance graph that gives a better picture of the impedance swings over frequency.

So as JRace said, the model and specs of the amp and speakers will provide a lot more useful information.  If you do hookup the paralleled 6Ω speakers, keep an eye (hand?) on amplifier temperature.  Many modem amps will have some kind of protection circuitry though, and would likely enter into protection mode to protect the amplifier from thermal destruction from too low load impedance.

Steve

[vonnie123]

It depends...

On the speakers and the amp.

To give a proper answer please provide the make and model of each.

Generally speaking most amps will handle a 3ohm load at low to moderate volume levels.

Here are the model numbers in question.

Wyred4Sound MC7x250

Monitor Audio Gold Signature GXFX
Monitor Audio Silver RS 1

Before I go the AVP route, I figured it was good to ask the question.  Appreciate your help on this.

[vonnie123]

It would be nice if most speaker loads were a constant resistance, but the impedance usually varies with frequency.  You might have an "8Ω nominal" speaker that has a minimum impedance of 3Ω at some frequencies.  That's why it's helpful for a speaker manufacturer to state the minimum impedance, and better yet, supply an impedance graph that gives a better picture of the impedance swings over frequency.

So as JRace said, the model and specs of the amp and speakers will provide a lot more useful information.  If you do hookup the paralleled 6Ω speakers, keep an eye (hand?) on amplifier temperature.  Many modem amps will have some kind of protection circuitry though, and would likely enter into protection mode to protect the amplifier from thermal destruction from too low load impedance.

Steve

Thank you.  I actually have a Sherbourn C12 fan system on top of the amp since its in a cabinet.  Temp gauge nearby too.  Never goes much over 90F, usually lower.

[JRace]

Cannot find impedance plots for those speakers.
Given they appear to be nothing exotic the chance of them dipping low is well...low.

As mentioned try it out, and keep an eye on the temp gauge.
Might be an issue given that your in a cabinet.

[G Georgopoulos]

speaker impendance for continues play is the impendance of the drivers,any instantaneous impendance has no effect on the amp,parallel impendance and series impendance of the drivers/speakers have similar effect only the impendance is changed...

[srb]

speaker impendance for continues play is the impendance of the drivers,any instantaneous impendance has no effect on the amp,parallel impendance and series impendance of the drivers/speakers have similar effect only the impendance is changed...

Only because you typed it SIX times .... the word is impedance .... 

[vonnie123]

Thanks for the replies.  Decided to not double up a pair of speakers, and purchased the receiver (instead of an AVP) which covers the two extra channels.

[THROWBACK]

"Only because you typed it SIX times .... the word is impedance ....  "

Mark Twain said, "It's a mighty poor speller who can think of only one way to spell a word."