Passive or active bi-amping

[onplane]

Since I started my thread on my positive experience with “passive bi-amping” my AR-3a’s. (that is, leaving the existing xovers in place) I’ve taken countless body punches on why this is a waste of time and why I can’t possibly achieve the results I’ve claimed.

Well, it seems, it’s a lot more complicated than many people suspect (I’ll get to that in a minute). Just wanted to once again confirm that I hear distinct differences and I have a control to compare against (my TSW610’s). My AR-3a’s under passive bi-amping provide:

1. better transient response

2. far better stereo imaging

3. bass that is better defined

4. clearer/cleaner high frequencies

5. amps running much cooler than before

I’ve been listening literally day and right now, I’m listening to Harry James. (Yeah, I know! You want to know what does Harry James have to do with jazz. Well his arrangements are extremely creative and then his solos ... well they are just out of the world! That guy could really blow that horn ... his TONE and his technique have never been matched as far as I’m concerned.) Anyhow, no one listens to the Harry James band at anything but a decent volume level.

Getting back on topic, I just checked the heat sinks on the output transistors on the AR1500 and if they are over 95 degrees, I’ll eat them. Something has changed!! They have never, ever run this cool.

From this I conclude it’s impossible that I’ve done ... nothing! Something has significantly changed.

Everyone says that passive bi-amping is a waste of time, only active bi-amping achieves anything. Well, in another thread Tom Tyson wrote:

“AR specifically advised against ever by-passing the crossover to utilize electronic crossovers, mainly because the network helps to “shape” the frequency response of the speakers to some extent.”

Turns out Tom is NOT the only one with this opinion. B&W has the following on their website:

“The term crossover is a little misleading. A multi-way speaker contains a crossover network that not only divides the incoming signal into different frequency ranges, appropriate to the working range of each drive unit, but also equalises each driver’s response to be flat (raw driver responses are usually anything but flat).”

They further have a very interesting article (it’s short):

http://www.bwspeakers.com/index.cfm/fuseac...67F00D0B7473B37

That ends with:

“The bottom line is that, unless you have access to the facilities to properly design and execute an active circuit for yourself and measure the acoustic results, don't do it!”

Then one of the guys with B&W’s actually called them and reported back:

“Yes, I have contacted B&W and they strongly suggest passive bi-amping if the customer have the means. They are against active bi-amping, however, because according to them, no matter what active cross over is used, it is sure to degrade the sound quality according to them.”

Another article:

http://www.bwspeakers.com/index.cfm/fuseac...67F00D0B7473B37

“Unlike bi-wiring, the load to each amplifier is different from that using a single amplifier full range. The voltage demands on each amplifier remain the same (each is still fed a full-range input and gives a full-range output), but the current demands are reduced. This of itself can improve the amplifier’s ability to deliver the signal to the speaker.”

Another individual put it this way:

“Referring to Bi-amping retaining the passive crossovers in the speakers: basically, the impedance presented to each amp is better behaved, because it is not the complex combination of both the high-and low-frequency crossovers in parallel. It eliminates all interaction of the low- and high-frequency crossover networks. It reduces current load on the amp, which may improve the sound.

According to B&W, they design their internal crossovers to help flatten out the inherently non-flat response of the drivers. If you bypass these circuits and use an active crossover, or even modify the existing crossover (better caps, etc.) they feel you may well degrade the sound. Read this:

http://www.bwspeakers.com/index.cfm/fuseac...67F00D0B7473B37

After reading all of this, I’m starting to feel a lot better about passive bi-amping. Further, I have had this Heathkit AR1500 for close to 40 years and IT HAS NEVER RUN THIS COOL! Something is different.

Anyhow, I’ve got to go now, Harry James and his band just enter my den and Harry is about to solo.

Regards,

Jerry

[ninohernes]

No body here is doubting what you heard, but you must remember that many of the people here are engineers who by nature try to quantify things objectively by using mathematics and measurements.

I am an exception. I do not really care about numbers and formulas. I quantify things by subjective observations. Sure, the math says that I only need 18 gauge speaker wire, but I use 10 gauge because I can hear a difference. I also spend lots of money on isolation devices to go underneath components to reduce the effects of microphonics. Some may say that this is bologna, but I hear a difference so who cares!!

I do have great respect for measurement and analysis. You need that. Without it, we would have no reference point, no standards to keep things on track. I also know how to interpret the collected data, which is just as important is knowing how to collect it. It is useless to have data if you don't know how to interpret it. However, I leave the data collection to the people who are skilled at this.

As I like to say, I don't design this stuff, I just drive it!

Anyway, do whatever makes you happy, and don't let anyone tell you otherwise. Just be mindful that you are doing something that is not recommended by the company, and there could be a risk. If you are OK with that, go ahead and have fun!!

[dynaco_dan]

>Since I started my thread on my positive experience with

>“passive bi-amping” my AR-3a’s. (that is, leaving the existing

>xovers in place) I’ve taken countless body punches on why this

>is a waste of time and why I can’t possibly achieve the

>results I’ve claimed.

>

>Well, it seems, it’s a lot more complicated than many people

>suspect (I’ll get to that in a minute). Just wanted to once

>again confirm that I hear distinct differences and I have a

>control to compare against (my TSW610’s). My AR-3a’s under

>passive bi-amping provide:

>

>1. better transient response

>2. far better stereo imaging

>3. bass that is better defined

>4. clearer/cleaner high frequencies

>5. amps running much cooler than before

>

>I’ve been listening literally day and right now, I’m listening

>to Harry James. (Yeah, I know! You want to know what does

>Harry James have to do with jazz. Well his arrangements are

>extremely creative and then his solos ... well they are just

>out of the world! That guy could really blow that horn ...

>his TONE and his technique have never been matched as far as

>I’m concerned.) Anyhow, no one listens to the Harry James

>band at anything but a decent volume level.

>

>Getting back on topic, I just checked the heat sinks on the

>output transistors on the AR1500 and if they are over 95

>degrees, I’ll eat them. Something has changed!! They have

>never, ever run this cool.

>

>From this I conclude it’s impossible that I’ve done ...

>nothing! Something has significantly changed.

>

>Everyone says that passive bi-amping is a waste of time, only

>active bi-amping achieves anything. Well, in another thread

>Tom Tyson wrote:

>

>“AR specifically advised against ever by-passing the crossover

>to utilize electronic crossovers, mainly because the network

>helps to “shape” the frequency response of the speakers to

>some extent.”

>

>Turns out Tom is NOT the only one with this opinion. B&W

>has the following on their website:

>

>“The term crossover is a little misleading. A multi-way

>speaker contains a crossover network that not only divides the

>incoming signal into different frequency ranges, appropriate

>to the working range of each drive unit, but also equalises

>each driver’s response to be flat (raw driver responses are

>usually anything but flat).”

>

>They further have a very interesting article (it’s short):

>

>http://www.bwspeakers.com/index.cfm/fuseac...67F00D0B7473B37

>

>

>That ends with:

>

>“The bottom line is that, unless you have access to the

>facilities to properly design and execute an active circuit

>for yourself and measure the acoustic results, don't do it!”

>

>

>Then one of the guys with B&W’s actually called them and

>reported back:

>

>“Yes, I have contacted B&W and they strongly suggest

>passive bi-amping if the customer have the means. They are

>against active bi-amping, however, because according to them,

>no matter what active cross over is used, it is sure to

>degrade the sound quality according to them.”

>

>

>Another article:

>

>http://www.bwspeakers.com/index.cfm/fuseac...67F00D0B7473B37

>

>

>“Unlike bi-wiring, the load to each amplifier is different

>from that using a single amplifier full range. The voltage

>demands on each amplifier remain the same (each is still fed a

>full-range input and gives a full-range output), but the

>current demands are reduced. This of itself can improve the

>amplifier’s ability to deliver the signal to the speaker.”

>

>

>Another individual put it this way:

>

>“Referring to Bi-amping retaining the passive crossovers in

>the speakers: basically, the impedance presented to each amp

>is better behaved, because it is not the complex combination

>of both the high-and low-frequency crossovers in parallel. It

>eliminates all interaction of the low- and high-frequency

>crossover networks. It reduces current load on the amp, which

>may improve the sound.

>

>According to B&W, they design their internal crossovers to

>help flatten out the inherently non-flat response of the

>drivers. If you bypass these circuits and use an active

>crossover, or even modify the existing crossover (better caps,

>etc.) they feel you may well degrade the sound. Read this:

>

>http://www.bwspeakers.com/index.cfm/fuseac...67F00D0B7473B37

>

>

>

>After reading all of this, I’m starting to feel a lot better

>about passive bi-amping. Further, I have had this Heathkit

>AR1500 for close to 40 years and IT HAS NEVER RUN THIS COOL!

>Something is different.

>

>Anyhow, I’ve got to go now, Harry James and his band just

>enter my den and Harry is about to solo.

>

>Regards,

>Jerry

Hi Jerry;

I'm still following your bi-amping idea and your experiences.

Makes for some very interesting reading.

Harry James, who is he? lol lol

Heath AR-1500 receiver, a really great piece of American engineering, my big bros built one.

I do feel that, if the AR-3A was being produced today, I would have suggested to AR, that they use three separate pairs of connections.

The tweeter circuit, the mid-range circuit and the woofer circuit individually terminate outside and a jumper joining each set of three terminal connections together.

For the stereophile buff, a two wire connection for typical operation and by removing the indiviual jumpers, for bi-amping or all the jumpers for tri-amping.

I am not suggesting doing that with an existing AR-3A speaker.

I am certain, this will bring forth some more interesting dialog, from our valued and interested members.

Good luck.

[onplane]

Hi, Joe!!

I'm NOT using active bi-amping, so I'm not in violation of AR's clear recommendation against removing the passive xovers.

I am using passive bi-amping and I don't think AR liked that either, but for entirely different reasons.

Common ground amps really became popular in the late 60’s early 70’s as more and more companies introduced solid state amps. In all fairness, if I were AR, I’d probably recommend against as well. No point in increasing your exposure to risk.

The only way I would bi-amp with your HF-89, Joe, is the way Tom Tyson suggested. That is, to totally isolate the woofer from the balance of the network and bring out a 4th terminal.

Regards,

Jerry

[ninohernes]

>

>The only way I would bi-amp with your HF-89, Joe, is the way

>Tom Tyson suggested. That is, to totally isolate the woofer

>from the balance of the network and bring out a 4th terminal.

>

>Regards,

>Jerry

>

If I were to biamp them, I definatly would!

There is no doubt in my mind that biamping has its sonic benfits, but I like AR speakers as is, and I have no desire to try and improve apon this allready excellent design. I like to sit back and enjoy them the way that they were designed to be used.

I am also a live sound engineer, and we quad amp our systems! Each driver in a 4 way stack gets an amp channel. We use digital loudspeaker management that allows me to change crossover slopes and points in real time. The system we use also has 16 bands of global parametric EQ and 6 bands of parametric EQ per driver. There is also delay for the enitre stack, and each individual driver so that you can time align the whole stack! This is when I get to have fun and play with big amps (litterally hundreds of thousands of watts!!!) crossover slopes, EQ, the whole nine yards!

[onplane]

Hi, Joe!!

>There is no doubt in my mind that biamping has its sonic

>benfits, but I like AR speakers as is, and I have no desire to

>try and improve apon this allready excellent design. I like to

>sit back and enjoy them the way that they were designed to be

>used.

Oh, I like AR's ... immensely. I have, however, more than one set. I was always happy with the 3a's until I got that set of TSW610's. The 610 can't compete with the 3a's in the deep base, but the mid-range and high frequencies were always much clearer/brighter.

After bi-amping the 3a's, I believe they out-perform the newer 610's in all areas. This is strange, but now the 3a tweeter even seems to out-perform that titanium dome tweeter in the 610's.

>I am also a live sound engineer, and we quad amp our systems!

>Each driver in a 4 way stack gets an amp channel. We use

>digital loudspeaker management that allows me to change

>crossover slopes and points in real time. The system we use

>also has 16 bands of global parametric EQ and 6 bands of

>parametric EQ per driver. There is also delay for the enitre

>stack, and each individual driver so that you can time align

>the whole stack! This is when I get to have fun and play with

>big amps (litterally hundreds of thousands of watts!!!)

>crossover slopes, EQ, the whole nine yards!

Holy S**T! What are you attempting to fill with sound, Joe, a football stadium?

Regards,

Jerry

[rrcrain]

There is an article concerning active biamping the AR90 in the library written by an AR engineer. It may well be worth reading and their advice probably has merit conceerning other speakers they manufactured.

http://www.classicspeakerpages.net/ar/ar-9...R_90_bi_amp.zip

[rrcrain]

Read the letter from AR concerning biamping the AR90 in the library. AR definitely did not have a "clear" policy against active biamping their speakers.

http://www.classicspeakerpages.net/ar/ar-9...R_90_bi_amp.zip

I suspect AR then, like Canton today, does and did not not actively promote active biamping out of fear that certain people would interpret this as a statement their crossovers were marginal and needed help or enancement. Think about it, who in their right mind would buy a speaker costing several thousand dollars from a manufacturer telling them "If you want really fantastic sound, spend another thousand on an active crossover." The marketing and engineering departments in almost all corporations seldom see things equally.

[onplane]

>There is an article concerning active biamping the AR90 in

>the library written by an AR engineer. It may well be worth

>reading and their advice probably has merit conceerning other

>speakers they manufactured.

>

>http://www.classicspeakerpages.net/ar/ar-9...R_90_bi_amp.zip

Richard, I had NOT seen this memo before!! Thank you for bringing it to our attention.

This memo CLEARLY supports Tom Tyson's comment about NOT removing the passive xover components. As always, Tom had it right!

Regards,

Jerry