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Bi-amping vs dual mono setup. Which would sound better?

Cajunchuck

Cajunchuck

Active Member
I was just thinking about adding a second power amp to my system in the future. What would provide the better sound between a bi-amp setup (one amp in stereo for the lows and another for the highs) and running a dual mono setup with bridged amps on each side? Assume the stereo amp by itself has more than enough power for the speaker's requirements. Really just curious to know the answer.
 
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The answer is...,

It depends on the sophistication of the crossover network used in the speaker. There are many higher end speakers where the crossover does more than just present a "low pass" for the woofer and a "high pass" for the tweeter. It contours/fixes abnormalities in various the components frequency response. For example, a band pass or notch filter may be incorporated to increase/decrease a portion of the band to correct for the driver's inherent frequency response "abnormalities." In a case like this, simple bi-amping, without further modification, may ruin the sound of the speaker.

On the other hand, if the speaker uses a simple low pass and high pass setup, biamping could be the ticket by reducing distortion and crossover phase shift while allowing you to better hone in on the optimum frequency and slope.
 
I would prefer 2 mono amps, Using 2 amps in stereo for high and low frequencies could result in mismatched levels between highs and lows, unless the stereo amps are the same
 
mikeybc said:
I would prefer 2 mono amps, Using 2 amps in stereo for high and low frequencies could result in mismatched levels between highs and lows, unless the stereo amps are the same
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When bi-amping, the volume for each amp is adjusted at the electronic crossover, and not at the amplifer. Also, each amp can best be selected for the load at hand. For example, you may want to use a tube amp for sweeter highs, but a solid state amp for tighter bottom end.

And, the amp pushing the highs doesn't need to be as powerful as the one pushing the bass.
 
E-Stat said:
I would prefer vertical bi-amping with one identical stereo amp driving each channel.

That would offer better separation and isolate the upper end from potential bass clipping.
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Again, why would the amps need to be identical?

Certainly you would want to use both channels of one amp for the highs and both channels of the other amp for the lows. But say you are using a 2-way with a 15" woofer (rated for 300 watts) and a compression driver/horn (rated for 25 watts), why would you ever want even need/want 300 WPC for the horn?

Really, that is just asking for trouble (and expense). For example, if one were to "make a connection that buzzes/clicks" between the crossover and the amp, the horn drivers are toast.
 
toddalin said:
Again, why would the amps need to be identical?

Certainly you would want to use both channels of one amp for the highs and both channels of the other amp for the lows. But say you are using a 2-way with a 15" woofer (rated for 300 watts) and a compression driver/horn (rated for 25 watts), why would you ever want even need/want 300 WPC for the horn?

Really, that is just asking for trouble (and expense). For example, if one were to "make a connection that buzzes/clicks" between the crossover and the amp, the horn drivers are toast.
Click to expand...

Read his post again, it makes perfect sense if you understand his post.
 
E-Stat said:
I would prefer vertical bi-amping with one identical stereo amp driving each channel.

That would offer better separation and isolate the upper end from potential bass clipping.
Click to expand...

OK..., reading Grenadeslio..., are you inferring a stereo amp bridged for each channel of the highs and a stereo amped bridged for each channel of the lows, and the amps for the lows do not need to be identical to the amps for the highs?

If one were to examine this case, why not just use four mono amps with twice the power and less expense?

One could also raise the question here..., does a bridged amp "sound as good" as a non-bridged amp as long as you stay well below the rated power (e.g., -10 dB)? Certainly bridging adds to the "parts count" and "complexity" and we all know that as far as sound is concerned, minimalism is a good thing..., don't we???
 
E-Stat was referring to vertical bi-amping. When speakers are vertically bi-amped one stereo amp is used for each channel. To wit: One channel of each stereo amplifier drives the highs (tweeter) and one channel drives the lows (woofers).

Horizontal bi-amping uses the same two stereo amplifiers. However one stereo amplifier is used to amplify the lows of both speakers. One stereo amplifier is used to drive the highs of both speakers.

Personally, I prefer vertical bi-amping because when a single channel bass/power hungry tone is amplified it's a drain on only one amplifier.

FWIW: I use a pair of bridged Crown's to drive dual subs. A pair of Dynaco mono blocks drive my speakers.
 
toddalin said:
Certainly you would want to use both channels of one amp for the highs and both channels of the other amp for the lows.
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That approach is called horizontal bi-amping and does not provide the beneficial left to right separation of using mono amps. Which is why the two amps need to be identical. One for the left. One for the right.

toddalin said:
But say you are using a 2-way with a 15" woofer (rated for 300 watts) and a compression driver/horn (rated for 25 watts), why would you ever want even need/want 300 WPC for the horn?
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Typically, one uses drivers with similar sensitivity. To the extent that the woofer does require more current, the lower demand of the other channel provides more power for the more needy one. Just as multi-channel amps provide more power in a stereo mode as they do running all channels simultaneously.

toddalin said:
OK..., reading Grenadeslio..., are you inferring a stereo amp bridged for each channel of the highs and a stereo amped bridged for each channel of the lows, and the amps for the lows do not need to be identical to the amps for the highs?
Click to expand...
My suggestion involves no bridging as that reduces an amplifier's ability to drive lower impedance loads as the effective impedance is halved. One stereo amp driving top and bottom for each channel.

toddalin said:
If one were to examine this case, why not just use four mono amps with twice the power and less expense?
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Four monoblocks would be ideal but I've yet to see where comparable mono amps are less expensive than a stereo amp. Twice the power supplies. Twice the casework.
 
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E-Stat said:
That approach is called horizontal bi-amping and does not provide the equivalent left to right separation of using mono amps. Which is why the two amps need to be identical. One for the left. One for the right.
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OK, I see what you are getting at and it does make sense for drivers of similar sensitivity. :bigok: Would be considerably harder for me or anyone tri-amping though.

I do think that one of the primary reasons that one would bi-amp would be because the speakers are of different sensitivities. But then, I always deal with big woofers and horns where sensitivies are widely different.
 
E-Stat said:
That approach is called horizontal bi-amping and does not provide the equivalent left to right separation of using mono amps. Which is why the two amps need to be identical. One for the left. One for the right.


Typically, one uses drivers with similar sensitivity. To the extent that the woofer does require more current, the lower demand of the other channel provides more power for the more needy one. Just as multi-channel amps provide more power in a stereo mode as they do running all channels simultaneously.


My suggestion involves no bridging as that reduces an amplifier's ability to drive lower impedance loads as the effective impedance is halved. One stereo amp driving top and bottom of each channel.


Four monoblocks would be ideal but I've yet to see where comparable mono amps are less expensive than a stereo amp. Twice the power supplies. Twice the casework.
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I've used both techniques for different reasons, passive and active, but prefer passive vertical bi-amping for home audio.

My twin Belles I amplifiers are very very close in serial numbers by design, they sounded sublime bi-amping my Infinity Modulus. Alas I wanted some of that Belles magic for the AR's in the living rm so the Infinitys are no longer bi-amped. Thanks to a member here I had the opportunity to grab a third at a ridiculous price, but snooze you lose. By the time I had decided to take it someone else was taking it for a test drive that weekend, I knew the game was up.
 
toddalin said:
OK, I see what you are getting at and it does make sense for drivers of similar sensitivity. :bigok: Would be considerably harder for me or anyone tri-amping though.
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Depending upon the low pass frequency, using a stereo amp for the subs/lower woofers might not impede perceived image width as low frequencies are less directional.

toddalin said:
I do think that one of the primary reasons that one would bi-amp would be because the speakers are of different sensitivities.
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My suggestion (like that of Grenadeslio) is for speakers that offer bi-amp terminals which both electrically separate the top and bottom sections along with matching sensitivity as if the speaker were driven with a single channel. And does not require an active crossover to be added to the mix. The only added piece would be another pair of speaker cables.

Returning to the original post, you can begin with a single stereo amp with the bi-wire/bi-amp jumper in place. Later, remove the jumpers and add the new stereo amp and speaker cables.
 
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Grenadeslio beat me to it! Just need a pair of three channel amps which are quite common in today's market for driving MC systems.

In the Linkwitz Orion/LX521 world, using a pair of five channel amps as is found in my HT system is typical. :)
 
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On the triamp issue, I wonder if I could vertical stack say the mid and high freq drivers and horizontal the woofers? I have identical amplifiers running mids and tweeters now but they are horizontal.
 
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