Why does bi-amping speakers sound better?


Curious why it sounds better to bi amp speakers vs just running them off one amp?

i am trying to figure out which amp to buy, I am on the fence with bi amp or not.  Speakers are the old infinity kappa 8.1's.  Several years ago when I was married I bi amped my speakers so each speaker was seeing two channels from a parasound hca1500, I think that's the model.... 200w x 2 going to each speaker.  I also tried a single amp powering both speakers so each speaker was seeing 200w x 1.  

is it that I simply doubled the power that resulted in better sound, mostly noticed the low end of the speakers was tighter, more powerful etc.... and obviously I could also play louder.  

Or is is there something about letting one amp not work as hard due to only running high frequencies while the other amp gets to just work on the low end.  

I am 90% sure which brand of amp I want to get, just trying to figure out if I should bi amp or not.

as a example should I go with

two 2 channel amps at 400w x 2 so each speaker would get 400x2

or should I go with a single 800w stereo amp so each speaker sees the same 800w, just with one channel of a amp



128x128viggen900

http://www2.rdrop.com/users/twest/audio/index.html


As discussed extensively below, the solution for the first two issues an active vertical biamp combined with low impedance cabling. The second two issues are addressed by balanced interconnects and reducing power amplifier gain—one of the odd things about audio is preamplifiers don't actually amplify. They attenuate. Line level out of a CD player is a few hundred millivolts RMS, but typical voltages at the drivers are maybe 100 mV RMS. In order to achieve a couple hundred watts of output power, power amplifiers have voltage gains around 30 dB. The preamp therefore ends up attenuating by 50 dB, meaning RMS voltages in preamp output stages, active crossovers, and power amp input stages are hundreds of microvolts. This exacerbates pickup of ground bounce or supply ripple coupling into power amp input stages and degrades op amp performance. The fix is simple; turn the power amp down and the preamp up. In an active biamp, unity power amplifier gain generally provides sufficient SPL and increases the SNR of most parts of the signal path by 30 dB. A secondary benefit is op amps behind the preamplifer's volume control operate closer to their line level sweet spot. With current generation op amps such as the LME49740 the benefit is small compared to speaker and power stage limitations, but there can be noticeable improvement in the volume control IC or with older op amps.

 


You are doubling not only your watts, but your power supply and head room. Addind a second, identical preamp has also made a difference in my system, because I can now have a bass control without changing any phasing through crosdovers. Since my amps do have huge power supplies , I have gone from bi-amping my mains to renning the second system on nicely matched subs.
Good point on redoing the wiring first.  However if I don't buy a amp I can't listen to my stereo. 

Its a old building as as I stated, 1865 is when it was built.  It's actually a apartment above one of my funeral homes, taking advantage of free/no rent for a while.  I believe I have a fuse panel upstairs in the attic so it probably will not be that difficult to rewire.  Paint, carpet then I need to find  out where the stereo sounds best before I run new power lines to a wall.  

This thread has been informative!!!  Thanks again everyone for their $.02 :)  I am still leaning towards bi amping these speakers, just need to figure out how much power to go with.  
Since you are dealing with old wiring, I would get an electrician to look at what you have, before buying an amp. 
If it will tax the existing wiring, you will not only not hear what you could achieve, but might not only damage your equipment, but may exacerbate a fire. Going over 200wpc is really sucking up juice.
audioman201581 posts02-10-2017 9:16amIn bi-amping, each amplifier drives a less complicated load. The drivers along with the crossover components have a complex impedance. It consists of a real load and then the imaginary part based on inductors and capacitors. This complex load also varies depending on the frequency of the signal. So if you have a 2 way speaker, the complete load a single amp will see is driver1+driver1 crossover+driver2+driver2 crossover. This is a much more complex load that the amp sees vs just driver1+ driver1 crossover.

Theres less complication by eliminating the passives it also equates to zero heat being generated within them relieving that much more strain from the amplifier. If the speakers have large complex crossovers with 1-3 big coils and 4-5 big caps you could be freeing up a good percentage of power that can then be routed directly to the drivers

I had once put together a small 30 x 4 channel Nad w Ashley pro crossover used to power some rather large mediocre efficient home made speakers, it did a fine job. Around $500 bought quite a lot of fun