Question about bi-wire and bi-amp

[edwelly]

Hello all - I know that bi-amp means using 2 amps, but can you use the A AND B channels on a receiver like in figure 1? If so, would this work and how would the sound differ?
And figure 2 would do nothing, right?

just trying to make sure I understand... Thanks!

 

[CaliHwyPatrol]

The B channel saps power from the A channel so you won't notice a difference.

 

[j_garcia]

Using A and B will get you nothing because most receivers run A and B in parallel off a single channel, so when you run both you are basically doing the same thing as biwiring from A (figure 2).

 

[furrycute]

Best thing to do is to use 2 identical amps.

1) 2 monoblocks. Each one amp powering a single speaker.
2) 2 stereo amps. 1 amp is connected to the high frequency connector on each speaker. 1 amp is connected to the low frequency connector on each speaker.


Bi-amp really brings out the bass in your speakers. I have a pair of stereo amps, so my setup is configuration #2. The bass really improved on this configuration. Right now it's like the woofers in my speakers are acting like subwoofers.

 

[MDS]

There are several different configurations that all get lumped together under the category of bi-amping:

1. One amp per speaker. You need two external amps - one to drive the left speaker and one to drive the right speaker. The potential advantage is that you now have a separate amp for each of the left and right channels and each has its own power supply rather than sharing the power supply of the receiver. This is not bi-amping in the true sense because you can accomplish the same thing using only 1 2 channel amp instead of 2 monoblocks (1 channel amps).

2. True bi-amping is actually using a separate amp for the tweeter and woofer. If you are using a receiver with pre-outs, you would have to use a Y splitter to split the single (left or right) channel into two so you can feed the two independent amps. The flaw in this approach is that each amp channel will still get a full range signal and the speaker's xovers will still have to separate out the frequencies - so you haven't really accomplished the goal of separate power to each driver. The only way this can be beneficial is if you instead use an active xover before the speaker so that each driver gets only the frequencies it can reproduce.

Using A+B on a receiver does neither of the two approaches above. How would you wire it? You can't achieve the goal of separate amplification for the woofer and tweeter because you would have to choose which channel is the tweeter and which channel is the woofer. Say you choose A for the Left speaker, then you choose the Left channel fof A or the tweeter and the Right channel of A for the woofer. Then you use B in the same way for the right speaker. Besides the fact that you would only hear the highs from the left channel and the lows from the right channel, which is bad enough, you have the exact same case as bi-amping with separate amps - each driver still gets a full range signal and has to split it out with its own xover.

Don't even think about using both A and B for both speakers.

Now if you want to use 4 speakers for the front and wire them normally with one pair on A and one pair on B that's fine, but A+B puts them in parallel and cuts the impedance in half, making them much harder to drive.

 

[furrycute]

2. True bi-amping is actually using a separate amp for the tweeter and woofer. If you are using a receiver with pre-outs, you would have to use a Y splitter to split the single (left or right) channel into two so you can feed the two independent amps. The flaw in this approach is that each amp channel will still get a full range signal and the speaker's xovers will still have to separate out the frequencies - so you haven't really accomplished the goal of separate power to each driver. The only way this can be beneficial is if you instead use an active xover before the speaker so that each driver gets only the frequencies it can reproduce.

I don't have an external crossover. So am I doing some wrong in my setup? I thought the speakers' passive crossover will suffice.

 

[MDS]

No, there isn't anything 'wrong' with it, it's just that the effectiveness of it is debatable. The premise behind bi-amping is to provide each driver with its own power. Without an external xover, each gets a full range signal - in other words the amp for the tweeter wasted its time amplifying the bass frequencies that will just get discarded by the tweeter anyway.

It doesn't hurt anything and some people swear it's an improvement anyway.

 

[furrycute]

Good point about each amp still amplifying a full range signal. Didn't consider that before.

But in order to utilize an external crossover, you need to disable the built in passive crossover. I'm not ready to do that, just yet.

 

[edwelly]

as always, thanks for clearing that up

 

[mulester7]

.....on a full-range, multi-element, speaker enclosure that is bi-wirable/ampable, how many sets, +/-, of input posts are on the back of said single speaker enclosure?....

 

[mtrycrafts]

.
But in order to utilize an external crossover, you need to disable the built in passive crossover. I'm not ready to do that, just yet.

Bypass it? Run an extra set of cables to the voice coil connection.

 

[mulester7]

Bypass it? Run an extra set of cables to the voice coil connection.

.....but you don't need to disable or bypass the passive crossover inside the speaker, which will receive watts....how many sets of posts are on a speaker that bi-wireable/bi-ampable?, please......

 

[MDS]

One pair of binding posts for each driver - so 2 pair for a 2 way speaker. I bet you already knew that anyway.

 

[mulester7]

One pair of binding posts for each driver - so 2 pair for a 2 way speaker. I bet you already knew that anyway.

.....well, MDS, to be honest, they used to be that way on auditorium big stuff like Altec, but these smaller ones in homes I wasn't so sure of....people keep saying they have the choice to run it full-range, or bi-wire it, or bi-amp it....I thought there could have been 3 sets of posts....but that would have brought the need for two independent systems of crossover....so, they're going to have to do it one way or the other....either bi-wire it, paralleling the top and bottom halves, or amp each half independently....is this correct?....

.....edit....gone for some Church's Chicken.....

 

[mulester7]

so, they're going to have to do it one way or the other....either bi-wire it, paralleling the top and bottom halves, or amp each half independently....is this correct?......

.....that is correct, mule, and wipe that chicken crumb off your chin, you fat butt....tell me, mule, what would you do with that speaker with two sets of posts?.....

 

[mulester7]

.....that is correct, mule, and wipe that chicken crumb off your chin, you fat butt....tell me, mule, what would you do with that speaker with two sets of posts?.....

......well, mule, I'll be honest seein' as how I like you....I would give that speaker every chance to perform as a 4 ohm speaker paralleling the top and bottom 8 ohm elements, and kick it with a strapped amp....correct, the strapped amp would need to do well delivering a 2 ohm load, because being strapped, it would see that 4 ohm speaker as a 2 ohm speaker, and fire 2 ohm bullets....thanks for the response, mule, take care.....

 

[Buckle-meister]

Funny.

Regards

 

[DDigitalguy06]

He will here a difference when he bi_wire he speakers!
The bass will be lot tighter and it wont sound so boomy. it will seperate from the highs. and it will sound alot cleaner!

 

[MDS]

He will here a difference when he bi_wire he speakers!
The bass will be lot tighter and it wont sound so boomy. it will seperate from the highs. and it will sound alot cleaner!

Bi-wiring does one and only one thing - it increases the effective gauage of the speaker wire. I would love to hear how a speaker wire can 'separate the highs from the lows'.

 

[brian32672]

He will here a difference when he bi_wire he speakers!
The bass will be lot tighter and it wont sound so boomy. it will seperate from the highs. and it will sound alot cleaner!

With this statement I would assume that you or someone you know, does this method.
At which point MDS above has stated the truth on this.
I use 10Awg wire for the front soundstage. Yes LCR. So by this statement, if I where to use 2 sets of 16Awg wire I would hear a difference.
Sorry, but that is just not true. Clearly a myth.