Jump to content
IGNORED

Bi-Amping Discussion


Recommended Posts

In the comments section of the MartinLogan Motion 40i review, biamping was raised. I am starting this new thread for an in-depth discussion of the topic. I find it endlessly fascinating and far more complex than some would have you believe. The notion that ripping out the passive crossover in your loudspeakers and connecting an active crossover will bring instant nirvana is simply bogus. My moniker on Audio Asylum is Audio Fan. I co-wrote this AA FAQ with another member in 2000:
https://www.audioasylum.com/messages/general/57210/biamplification-basics-an-article 
I am happy to say that I still agree with virtually everything in the FAQ.

Vertical Biamping
"The purpose of vertical biamping is to reduce the current demand on an amp. Because the main current draw is in the low frequencies, each power amp in a vertical setup only drives one woofer. The channel driving the woofer gets to hog most of the current provided by the amp's power supply, since the channel driving the high frequencies doesn't need as much current. This is particularly advantageous if the amp uses a common power supply for both channels. Vertical biamping in this manner requires identical amps for each channel to maintain balance integrity."

 

I have a pair of 50W stereo amps. Driving my 4-ohm 89dB/W/m speakers with a single stereo amp sounds OK. Driving the speakers biwired to a single channel of both amps sounds much better, more detailed, more dynamic, tighter bass. There is a small further improvement when I drive the speakers in vertical biamp mode. I no longer use the 50W stereo amps in my main system because the Meitner 100W monoblocks sound best, so clearly biamping is no panacea.

 

Horizontal Biamping
"In horizontal biamping, one stereo amp is connected to the low-frequency speaker posts on both the left and right channel, and a second stereo amp is connected to the high-frequency posts of the left and right speakers. This arrangement is used for biamping with dissimilar amps.

The purpose of this arrangement can be to maximize the virtues of different amplifiers. If amp X has superb bass and amp Y is a bit soft on bass but has a glorious mid and top then amp X is used for low end reproduction and amp Y for the upper end of the spectrum."

 

I tried horizontal biamping with a 50W Meitner in combination with various other SS amps (50W NAD, 70W Classe, 100W Bryston). While I could easily achieve better bass and treble with these combos, none were as satisfactory as a single stereo amp powering both channels. In all cases, the horizontal configuration resulted in a loss of coherence. The sound was more hi-fi, less musical and quite disappointing. I did not experiment with tube amps, but I find it very hard to believe that a SS/tube amp combo would make me happy, due to the different sound signatures. I don't doubt that some combination of gear and sonic preferences may arrive at a different conclusion on the merits of horizontal biamping. 

 

I have been experimenting with active and passive systems for twenty years. I currently own a Marchand XM44 three-way active analog crossover, a two-way Marchand XM46 passive line level crossover, a miniDSP 2x4 digital crossover and several pairs of FMOD inline crossovers. Even though I have these crossovers, I am running my (sealed) monitors full range with the subs connected in parallel to the main speakers, via the miniDSP (BW2@63Hz Low Pass, with Linkwitz Transform and correction for the main room node (-12dB@42Hz, Q=5)).

 

The main reasons I have settled on the above configuration are listed in the AA FAQ:

1. Quality speakers are designed with a crossover network matched to the particular characteristics of the drivers. Substituting an active crossover defeats the speaker designer's efforts to truly match the drivers, cabinet, and crossover together.

2. Anything that is added to the signal path alters it in some way. Passive components do too (a cable is a passive component, for example), but they may be less likely to add coloration than active components.

3. An active crossover performs a sophisticated function, roughly similar in complexity to a phono stage. An active crossover has the potential to degrade the sound of a system if its quality does not match the rest of the components.

Ultimately arguments for or against either configuration are academic - the proof is in the listening. 
As with all links in the chain, the quality of the active crossover influences the sonic result. A poorly designed active crossover might not yield better results than the internal high quality passive crossovers in a well designed loudspeaker with components carefully matching the drivers.

 

The reason not listed above is that I value simplicity these days, I don't want to go back to tri-amping, though I admit the miniDSP SHD Series processor/streamers are a temptation, LOL!

 

All comments are welcome. 

Main System: QNAP TS-451+ NAS > Silent Angel Bonn N8 > Sonore opticalModule Deluxe v2 > Corning SMF with Finisar FTLF1318P3BTL SFPs > Uptone EtherREGEN > exaSound PlayPoint and e32 Mk-II DAC > Meitner MTR-101 Plus monoblocks > Bamberg S5-MTM sealed standmount speakers. 

Crown XLi 1500 powering  AV123 Rocket UFW10 stereo subwoofers

Upgraded power on all switches, renderer and DAC. 

 

Link to comment
3 hours ago, semente said:

What's wrong with the KISS principle?

Do you mean why not just stick with a passive loudspeaker and one amp? Yeah, definitely the best option for most people. Experimenting is fun though, a way to get more personalized sound quality, and can provide superior performance if done well. The downside; it can be tortuous.

Main System: QNAP TS-451+ NAS > Silent Angel Bonn N8 > Sonore opticalModule Deluxe v2 > Corning SMF with Finisar FTLF1318P3BTL SFPs > Uptone EtherREGEN > exaSound PlayPoint and e32 Mk-II DAC > Meitner MTR-101 Plus monoblocks > Bamberg S5-MTM sealed standmount speakers. 

Crown XLi 1500 powering  AV123 Rocket UFW10 stereo subwoofers

Upgraded power on all switches, renderer and DAC. 

 

Link to comment
32 minutes ago, Ralf11 said:

 

did you miss this: "the loudspeakers they make"

Sorry, I did indeed.

Main System: QNAP TS-451+ NAS > Silent Angel Bonn N8 > Sonore opticalModule Deluxe v2 > Corning SMF with Finisar FTLF1318P3BTL SFPs > Uptone EtherREGEN > exaSound PlayPoint and e32 Mk-II DAC > Meitner MTR-101 Plus monoblocks > Bamberg S5-MTM sealed standmount speakers. 

Crown XLi 1500 powering  AV123 Rocket UFW10 stereo subwoofers

Upgraded power on all switches, renderer and DAC. 

 

Link to comment
3 hours ago, photonman said:

What about the "dual-mono" single chassis amps out there, do they qualify as biamping too?  Specifically if you have an amp with a seperate power supply and amp board for each channel but only one common mains connection, do you get the same benefits of bi-amping?  Seems you would stay within KISS parameters.

The amp you describe is a stereo amp. You need two stereo amps for biamping. 

Main System: QNAP TS-451+ NAS > Silent Angel Bonn N8 > Sonore opticalModule Deluxe v2 > Corning SMF with Finisar FTLF1318P3BTL SFPs > Uptone EtherREGEN > exaSound PlayPoint and e32 Mk-II DAC > Meitner MTR-101 Plus monoblocks > Bamberg S5-MTM sealed standmount speakers. 

Crown XLi 1500 powering  AV123 Rocket UFW10 stereo subwoofers

Upgraded power on all switches, renderer and DAC. 

 

Link to comment
13 hours ago, Abtr said:

What do you mean by "improper driver timing"? Phase errors or impulse-response errors or both?

I was thinking primarily of phase. For example, where the woofer drops by 6dB/octave due to its internal inductance, so a 2nd-order Butterworth is used with 3rd order on the tweeter for a final BW3 transition.  

Main System: QNAP TS-451+ NAS > Silent Angel Bonn N8 > Sonore opticalModule Deluxe v2 > Corning SMF with Finisar FTLF1318P3BTL SFPs > Uptone EtherREGEN > exaSound PlayPoint and e32 Mk-II DAC > Meitner MTR-101 Plus monoblocks > Bamberg S5-MTM sealed standmount speakers. 

Crown XLi 1500 powering  AV123 Rocket UFW10 stereo subwoofers

Upgraded power on all switches, renderer and DAC. 

 

Link to comment
18 hours ago, Kal Rubinson said:

You need two stereo amps for biamping in stereo.  What he was asking about was something else.

I don't understand what you mean. The Bryston 3B-ST for example is a dual mono amp, it has separate power supplies for each channel, but both channels are amplifying bass and treble frequencies. Using a single 3B-ST for stereo does not fit the definition of biamping, where bass and treble are handled by separate channels.

 

I have friend who uses a pair of 3B-ST's in vertical biamp mode with B&W N802 speakers. Biamping is notably better than a single 3B in his system due to double the current capacity and lower IM.

Main System: QNAP TS-451+ NAS > Silent Angel Bonn N8 > Sonore opticalModule Deluxe v2 > Corning SMF with Finisar FTLF1318P3BTL SFPs > Uptone EtherREGEN > exaSound PlayPoint and e32 Mk-II DAC > Meitner MTR-101 Plus monoblocks > Bamberg S5-MTM sealed standmount speakers. 

Crown XLi 1500 powering  AV123 Rocket UFW10 stereo subwoofers

Upgraded power on all switches, renderer and DAC. 

 

Link to comment
2 hours ago, Abtr said:

Possibly. I successfully use an active LR4 for crossing my main speakers and sub, but I never tried bi-amping a tweeter and a mid/bass driver. I'd probably use something like a miniDSP for that.

I have one, but there's no way I'm going to run my main speakers through a miniDSP, the quality is just not sufficient. Their SHD Studio looks interesting though.

Main System: QNAP TS-451+ NAS > Silent Angel Bonn N8 > Sonore opticalModule Deluxe v2 > Corning SMF with Finisar FTLF1318P3BTL SFPs > Uptone EtherREGEN > exaSound PlayPoint and e32 Mk-II DAC > Meitner MTR-101 Plus monoblocks > Bamberg S5-MTM sealed standmount speakers. 

Crown XLi 1500 powering  AV123 Rocket UFW10 stereo subwoofers

Upgraded power on all switches, renderer and DAC. 

 

Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



×
×
  • Create New...