What does bi-amping do?

[rigma]

Another option is a passive crossover between the pre amp and power amps. I use the Marchand XM46 with great sucess.

Rigma

[heresy2guy]

I understand what you're saying, Tony. PWK did many experiments on many things and his feeling, based upon my reading, was that a measurable improvement needed to be taken into consideration with the cost associated to implement it. One of the DFH articles mentions tri-amping as something that could produce measureable improvements, but questions whether or not said improvements could be easily discernible by the naked ear...particularly with respect to it's additional cost. Many people are now paying premium prices for en vogue hybrid vehicles (Toyota Prius comes to mind) but fail to realize that they might have to drive a hundred-thousand plus miles just to recoup their original, premium sticker price via their fuel savings.

PWK dismissed a lot as BS, you have to take into account his VERY strong bang for the buck mentality. when something wnet above his personal metric he imeediately dismissed it.

Let's also remember that PWK worked with Brook to develop a special amplifier that split taps of the output trannies and added circuitry to essentialy triamp klipschorns.

just as we've posited benefits of steep slope crossovers and we can see differences between different drivers and the ideal power for those drivers (wattage, current draw and impedance) we should see some potential benefits of triamping, electronic crossovers, etc.

IMHO of course.

tony

[Guest " "]

ditto on all the comments so far....not mentioned is using bi-amping or tri-amping to actually get more power into an installation. when comparing cost..one large amp not bi-amp or tri-amp or 2 or 3 small amps that are bi-amped or tr-amped.

[djk]

Cost for a dedicated bi-amp for Klipsch Heritage type speakers would be very cost effective. A very high quality HF amp of about 10W and a good 50W LF amp would cost far less than a large full range amp that sounded merely good. The crossover would cost virtually nothing, the main cost here is the chassis, supply, and jacks; all shared with the amps.

• Posted by

djk ( M ) on September 20, 2003 at 12:30:27

In Reply to: Biamping - I had no idea. posted by mikemalter on September 18, 2003 at 22:14:48:

"Let us adopt the phrase 'duo-amping' to distinguish bi-amp(using a frequency dividing network ahead of the amps)from the practice of using two amps with their inputs wyed together driving the speaker crossover sections.The phrase 'vertical bi-amping' has low popularity and is too similar.All it will take is a little concerted effort to eliminate the confusion."

http://db.audioasylum.com/cgi/m.pl?forum=general&n=7542&highlight=duo-amping&r=&session=

"If you use an electronic crossover and bi-amp a speaker like a Klipsch

Cornwall

with a 50W amp on the bass and a 10W amp on the mid and hf it will play as loud as a 400W amp through the passive crossover.

If you 'bi-amp' your Newform speakers with a 250W amp on the bass and a 160W amp on the hf without an elecronic crossover it will play as loud as the 160W amp would play running both.

The 4:1 benefit for bi-amping is only there when the spectrum is divided ahead of the power amps and when the division point is near the mid point of the spectral distribution of energy.On a voltage basis the division occurs around 250hz.This must be weighted by the peak to average ratio so that the equal energy point for above and below the crossover is about 500hz.This is also affected by the slope of the crossover.For the example of the Klipsch

Cornwall

it has a 600hz crossover point.If the drivers were the same efficency then 50W + 50W would = 200W through the passive crossover.In reality the HF is 10dB more efficent than the LF so we only need 50W + 5W to = 200W.If the HF remains undistorted it will mask distortion from the LF amp driven slightly into clipping.

This means that if we use a 10W HF amp with a 50W LF amp it would take 400W to play the same level undistorted through the passive crossover.

If you 'bi-amp' your Newform speakers without an electronic crossover each amp will be receiving full range signal and will clip at the same point it did with only one amp hooked up to the speakers.It does sound different to do this, but make no mistake, you will not be getting the benefits of dividing the signal ahead of the amplifiers."

http://db.audioasylum.com/cgi/m.pl?forum=general&n=164118&highlight=

cornwall

+bi-amp+

djk

&r=&session=

[Guest " "]

anyone one to take a shot at some equipment recommendations, or report on their configs?

[steamer]

anyone one to take a shot at some equipment recommendations, or report on their configs?

Well here is my configuration:

I run LaScala bass bins and Altec 511b's with the 902 drivers.

My signals are divided with a Rane Mojo 2way active at 400hz.

The Altec's are powered by a pair of Wavelength Gemini 45/2a3 monoblocks(2 to 4 watts depending on tube)

The bass bins are powered by a Bryston 3B pro SS amp(130 watts per)

Also I run a dedicated BagEnd sub system powered by another Bryston 4B pro amp(250 watts per)It has an integrator/x-over that recieves the signals below 400hz from the Rane and further divides it at 70hz before those signals go to the SS amps.

My Brystons have input level control and are trimmed back otherwise when you get on the volume the bass tends to overpower the rest.Also I find I have an envelope of volume where if I want to really turn things up I have to adjust the bass level down on the Rane 1 to 2 db or if you play a bass heavy disc you can trim the Ranes bass level.Very convienient and easy to do with one knob.I find I dont have to do this often but like the ability to do so.

I have listened to LaScala's for 20 years with 2channel SS gear and the last couple with PP tube monoblocks.6 months ago I went to active biamping and cant shut it off(my tube bill this year is gonna hurt lol)Every aspect of the sound is better.95% of the music put in stays in for almost every song.I listen at lower volumes now as well.Before I was always turning it up and skipping to the next song.I am amazed everyday by this system.I used to have a 50 in bigscreen and makeshift home theater setup in between the Scala's but have chosen to move it upstairs and make this room a dedicated 2 channel setup.Hell I never watch TV anymore.I have 2500 plus CD's and am rediscovering my collection.

I have a friend on another forum that has just put together a similar rig running 2way with tubes for the highs and SS for lows.His impressions are the same as mine in that he cant believe the difference and will never go back.

I will say that I made alot of changes 6 months ago and this is not an example of just getting another amp and an active x-over.I spent a year getting all the various components together and completely transformed the system.

My recommendation is that if you can try biamping with an active x-over before the amps do it to hear it for yourself.You can always go back if you dont like it.I cant imagine anyone going back if they have set it up correctly and hear the benifits.But we all have our preferences for sound.Remember its important to have level controls(at least for the higher powered amp).I could have gotten by with less power for my SS amps...but then I could control input level.The post by dkj seems like a good guideline for power requirements or ratios between highs and lows.

I'll never go back!

Greg