Impediance rating change? Bi-amp

civilian

I can't seem to find out what the change in impediance would be when changing to a bi-amped setup with my RTi70(or rt55's). Any help would be apreceated.

John K.

Civ, welcome. The reason that you haven't been able to find the change in impedance is that there isn't any. In a nominally 8 ohm speaker(impedance varies with frequency, but that's another matter)both the bass section and the treble section are 8 ohms and passive biamping can't change that(or anything else of significance). Just in case you've gotten the idea somewhere that passive biamping doubles the power, or increases it in any way, there's no factual basis for that. The same power supply section is just routing the available power through two sets of output transistors rather than one, but nothing is increased.

reeltrouble1

No impedance change but its a great thing to try out and see how you like the sound, many folks here enjoy bi-amping their systems with great results. Ken Swauger at Polk who is the head guru around these parts recommended bi-amping to me years ago.

Now you are using two amplifiers? Or do you mean bi-wiring?

RT1

civilian

John K. wrote:

Just in case you've gotten the idea somewhere that passive biamping doubles the power, or increases it in any way, there's no factual basis for that.

Thankyou John, what do you mean by passive biamping(hopefully not "bi-wiring")? I have often wondered what sonic gains I could achieve by adding a second set of amp channels from my Denon 4806 for 2-channel audio.

civilian

reeltrouble1 wrote:

Now you are using two amplifiers? Or do you mean bi-wiring?

RT1

I was typing my post when you posted. Yes two amps, or at least 4 channels of amplifaction instead of 2, I have often wondered what sonic gains I could achieve by adding a second set of amp channels from my Denon 4806 for 2-channel audio.

John K.

No, "passive" biamping isn't biwiring. The term is used to distinguish it from "active" biamping in which separate amplifiers are preceded by an external crossover(requiring that the internal crossover in the speaker be removed or bypassed), so that each separate amplifier only receives and amplifies a specific frequency range rather than the full range. Your 4806 would simply send full frequency range from its power supply through both sets of output transistors, and this would then be processed through the internal crossover in the speaker, as usual. No power increase or other audible benefit would result, despite wishful thinking to the contrary.

F1nut

or other audible benefit would result, despite wishful thinking to the contrary.

How about you let him decide that for himself instead of plying your usual pile of ignorant BS.

BaggedLancer

F1nut wrote:

How about you let him decide that for himself instead of plying your usual pile of ignorant BS.

wow, harsh

george daniel

BaggedLancer wrote:

wow, harsh

Nope,,:)

reeltrouble1

Civilian,

I just heard some Anthem amps bi-amped, they were very sweet sounding to say the least. If you have the capability to try it you should. Just make sure you remove the jumpers from each speaker and carefully wire everything up. You will not be "doubling" the power though, many folks get better deeper bass extension with a bit sweeter top end and wider stage, some folks dont like to bi-amp and do other things, there really is no "one" way to do anything in audio.

Mr. K always says things like that, that we're all delusional, no difference in sound and so on, he is sort of a fanatical anti hi-fi audio insurgent, all the regulars here know and pay no mind so the newer members are normally targeted by him.

Sorry you got dinged. In the end you just have to try things and see how you like them, however, you pretty much get what you paid for, so you have a nice Denon and can work from there.

RT1

amulford

John K. wrote:

. No power increase or other audible benefit would result, despite wishful thinking to the contrary.

Hold on a minute, there whistled!ck. If you biamp, you get, and I quote, "No power increase"? That may be true if you change the amplifiers to half of the output you currently have. But if you double it, ie add another amplifier of equal rated power output, you most certainly do increase the power. By two fold. This in turn gives an increase of roughly 3 db SPL, but more importantly allows a greater margin of reserve headroom for tighter control of the driver and increased transient dynamic response.

You're so full of **** your blue eyes turned brown...

Civilian,

In your case, I wouldn't recommend doing it that way. IMHO, I'd find an amp with close to the same output and use it to drive the lower end. YMMV.

wingnut4772

Would the same effect be accomplished by getting a more powerful amplifier in general?

amulford

Yes.

reeltrouble1

Or put the big amp on the bottom to run the bass and the leeetle amp on the top to run the tweets.

RT1

civilian

this would then be processed through the internal crossover in the speaker, as usual.

I was thinking that Bi-amping was designed to bypass the internal crossover in the speaker, using a pre-amp instead?

PolkWannabie

The internal crossover is not bypassed ...

tonyb

F1nut wrote:

How about you let him decide that for himself instead of plying your usual pile of ignorant BS.

Ya just gotta love it man!!:D

reeltrouble1

No not bypassed, just no way for the signal to be sent down or up the wire once the jumper is removed, Still filtered though otherwise you would have a tweeter trying to play a full range signal and viceee-verceee. So when bi-amped the speaker's driver is only going to use what it needs from each amp. Bass takes more current than treble so better to put the bigger amp on the bottom.

RT1