2. speakers
  3. 125541-80275

Bi-amping Rules

I wasn't sure if this question belongs in the amp or the speaker section but I figured I'll post it here. Those of you who have bi-amped your speakers, what's the general rule for deciding which amplifiers are better for low frequency vs. the high frequency drivers. I recognize an accurate answer will depend on the particular speakers and amp combinations but I'm looking for general rules of thumb from personal experiences and not application specific recommendations. For the sake of the argument, let's assume the amps are different but the gains on both amps can be adjusted if that matters. Thanks.
128x128kalali
georgelp's avatar
georgelp
4 posts
 

I can’t tell y’all how many times in the last 40 years of my career in A/V people have always missed the first fundamental. They pile up a stack of humming electronics and wonder why their performance is underwhelming. Think about power first. Add up the greedy electrical cravings of all the equipment - then spot it all an additional 25%. You need the available power to do what you want and give the amps a chance to breath. Keep in mind a 15amp a/c circuit has 1800 watts available and a 20amp has only 2,400 (both with 120volt US standard). And be sure to add up every bit on that circuit - be sure to include lamps, clocks, and chair warmers!

Two 1,000 watt per channel amps, preamp, tuner, DVD, computer, cable box, D/A, equalizers, monitors, and that neon lit beer sign with the dogs playing poker are going to suck dry a 15amp circuit. Your result will be a rather anemic.

audiofreak1954
13 posts
 
For me..... low end must have high damping factor, tubes on highs SS on bottom and yes tramping is even beter. I've even heard quad and more amping. Basically I feel it about control.
kraftsound
14 posts
 
Let's leave PA-systems out of the discussion. In them you want efficiency and the most bang for the buck at the least weight to haul around. You also have a brain behind the console to tweak the sound as he pleases and the music is produced rather than reproduced so there is no original to compare with. That is not to say that you don't need good sounding amps etc to get the venue rockin' and a satisfied audience that leaves saying that the sound system was the best they had ever heard...

Can you use different amps for hi/lo in a HiFi-system? Yes! But I recommend using similar amps. I used Nakamichi N620+N420+EC100 for many years and the sound was very balanced. Of course this configuration was intended by the manufacturer. My guess is that eg Linn LK140+LK85 would perform even better as they are also two versions of the same series of amps but with different power ratings.

If your speakers are simple 2-way with just a coil and a capacitor for filtering my recommendation is using two identical stereo-amps with one placed behind each speaker and low level passive x-overs that only employs 2 resistors and 2 capacitors for each channel. This is very simple, keeps the speaker cables short and leaves most of the PSU in the amps available for the woofers.

If the speakers have complex filters they usually not only divides the range and adjust levels but also includes phase correction components that may require some kind of delay line in the active x-over and you are in for a big challenge...
danvignau's avatar
danvignau
935 posts
 
I prefer two identical amps and preamps. This way, I can adjust the bass or recordings lacking such. I tried alternate ideas, but there is a tradeoff with phasing. 
midareff1
182 posts
 
I bi-amp with two identical amps, and I mean identical.  Despite being about 25 years old they are 5 numbers apart (serial number) built on the same day, same shift, same parts bins.  One amp runs the left speaker and one the right.  The left channel of each drives the woofer module and the right the electrostatic panel of a very power hungry vintage pair of Acoustats. 
More to discover