Bi-amping and Bi-wiring

[onplane]

As many of you know, I'm a firm believe in the benefits of bi-amping and believe bi-wiring is a total waste of time and money.

Well, in order to be fair, just thought I'd share an article by a well respected company that has a different opinion. They believe that most of the benefits of bi-amping can be achieved though ... bi-wiring!!??

To say the least, I was a bit shocked when I read the article. Further, their explanation that the fields created by current in the speaker wires causes the difference is actually ... plausible.

Anyhow ... it's an interesting read:

http://vandersteen.com/pages/Answr7.htm

Regards,

Jerry

[tysontom]

>As many of you know, I'm a firm believe in the benefits of

>bi-amping and believe bi-wiring is a total waste

>of time and money.

>

>Well, in order to be fair, just thought I'd share an article

>by a well respected company that has a different opinion.

>They believe that most of the benefits of bi-amping can be

>achieved though ... bi-wiring!!??

>

>

>To say the least, I was a bit shocked when I read the article.

>Further, their explanation that the fields created by current

>in the speaker wires causes the difference is actually ...

>plausible.

>

>Anyhow ... it's an interesting read:

>

>http://vandersteen.com/pages/Answr7.htm

>

>Regards,

>Jerry

>

>

Jerry,

Have you considered taking your suggestions and comments on modifying AR speakers over to the "Mods, Tweaks and Upgrades to the Classics" section and away from the main-stream section on AR speakers themselves? For sure, you are sincere and dedicated in your pursuits -- and some of your ideas might be fine -- but overall it is distracting to the general purpose of preserving and enjoying the AR classics. I suspect that most people want to restore their classics, not modify them.

It would be interesting to hear from others on this forum how they feel about this sort of thing. Maybe the consensus prefers to leave it the way it is; others might want to keep the mods and tweaks in another section, readily available to readers who are interested in doing that sort of thing.

--Tom Tyson

[onplane]

Tom,

If that's what folks want, I'd be happy to comply.

For the record, bi-wiring is NO mod. Speakers remain as they are, just another way to power. Some folks believe it improves sound. Frankly, I've never believed there was anything to it until I read the article I referenced.

As for bi-amping AR speakers (that only have 3 terminals and I believe AR is really unique in that), I believe that that belongs on the AR forum.

Now, that I think about it, I 've never seen a speaker system with 3 terminals. Tons with 4, but 3? I think AR is unique in that.

Regards,

Jerry

[Shacky]

Jerry,

While I'm past the initial learning stage on AR's, I do think it can be confusing to members asking about restoration information and getting suggestions on bi-amping as well as modifying/bypassing the rheostats. Seems to me that majority of this type of posting has your suggestions in them.

Not to detract from a fellow Rochestarian, I think the bi-amping suggestions would be more appropriate in Mods/Tweaks per Tom's suggestion. Almost seems like you are trying to over-sell it by infusing into nearly every discussion on this forum.

Just my thoughts.

Jim

[rrcrain]

The conversation probably should be moved as the public has spoken, but I'll make one comment before it is moved.

Been there, done that and my experience is it's snake oil. I know a few others personally who have tried bi-wiring and and have the same opinion. In fact, I know of no one personally that thinks it works.

I read an article a few years ago that backed up their claim with mathmatics showing it "could" make a difference BUT, the effect was so incredibly small the author strongly suggested investing money elsewhere other than in wire.

[Steve F]

I remember a demo that noted reviewer Tom Nosaine did at a Boston-area AES meeting about 10-12 years ago, where he debunked the notion that special "audiophile" cables, interconnects, bi-wiring and the like made any difference whatsoever.

This mirrored an article he wrote for Stereo Review in the mid-90's, where he did a very tightly-controlled double-blind test of two systems: one was an audiophile system with nutso speaker cabling, esoteric amps, high-end CD player, etc. The other was a garden variety system with mass-market CD player, a 1970's vintage Heathkit receiver, regular 'ol speaker wire, etc. The systems fed the same speakers, in the same location.

Despite a golden-eared listening panel, there were NO statistically-significant correlations of listening quality attributable to either system. None.

Bi-wiring/bi-amp terminals is more of a marketing-driven requirement for speakers than anything else. There are some markets (Europe, the Far East) where double inputs are 'gotta have.' Also, many reviewers tend to like 'em.

But normal people don't use them, hardly ever. A fancy bi-amp terminal raises the cost to the manufacturer by about $4.00 compared to a regular terminal, which translates into a $15-20 retail price increase. It's a waste.

Steve F.

[Carlspeak]

As I've written a number of times before, 'sonic beauty is in the ear of the beholder'.

Who's to say with any degree of certainty that the myriad of combinations of wires, amps, speakers, etc, out there in the marketplace couldn't yield some percentage of synergistics effects detectable by the listener?

A random test here and there does not yield a conclusive result - any more than my single AR pot setting measurements posted in another thread here.

It's all about the music

Carl

Carl's Custom Loudspeakers

[RoyC]

>I think the

>bi-amping suggestions would be more appropriate in Mods/Tweaks

>per Tom's suggestion. Almost seems like you are trying to

>over-sell it by infusing into nearly every discussion on this

>forum.

I completely agree with Jim's comment.

Roy

[RoyC]

>Who's to say with any degree of certainty that the myriad of

>combinations of wires, amps, speakers, etc, out there in the

>marketplace couldn't yield some percentage of synergistics

>effects detectable by the listener?

Ah, that is exactly what keeps the snake oil salesmen in business. Even if there are "differences" who is to say they are improvements?

In the end it is in the ear, mind and pocketbook of the beholder.

Roy

[Carlspeak]

>>Who's to say with any degree of certainty that the myriad

>of

>>combinations of wires, amps, speakers, etc, out there in

>the

>>marketplace couldn't yield some percentage of

>synergistics

>>effects detectable by the listener?

>

>Ah, that is exactly what keeps the snake oil salesmen in

>business.

AMEN!

Even if there are "differences" who is to

>say they are improvements?

The customer who believes he does hear a difference which his pocketbook can handle.

I'm a believer that if a sonic difference is detectable to a large group of listeners under reasonably controlled conditions, then it more than likely is significant. However, if some hear a difference and some don't, then it is not signifant enough to get excited about. I refer you to a DIY'rs cap listenint test Pete Basil has referenced in a few posts here. In any case, it's evident the final decision still lies with the customer and his wallet.

>

>In the end it is in the ear, mind and pocketbook of the

>beholder.

>

>Roy

>

>

It's all about the music

Carl

Carl's Custom Loudspeakers

[soundminded]

>Ah, that is exactly what keeps the snake oil salesmen in

>business. Even if there are "differences" who is to

>say they are improvements?

>

>In the end it is in the ear, mind and pocketbook of the

>beholder.

>

>Roy

This issue of subjective relativism, one opinion being as valid as another has an appeal to our non judgemental egalitarian nature which we have been trained for in our modern society but I have a different take on it. As CD players, amplifiers, wires, perform strictly electrical functions they can and should be evaluated by purely electrical performance standards and compared to an ideal model of their function. In some cases this is actually easy to test in practice such as by substituting a shunt for a wire. The closer the wire in the circut sounds to the shunt, the better it is whether you prefer it or not. In comparing two CD player of two different eras, a 1 bit JVC player costing $200 purchased in 1991 and a $45 24 bit Toshiba DVD player purchased in 2006 using duplicate (factory made) discs exactly synchronized, I came to the conclusion that they were subjectively indistinguishable, surprisingly even in their output level. I concluded that both performed their functions subjectively perfectly. I have never been able to detect any audible difference between a $1 interconnect and a shunt which hardly surprised me since they are also flat from DC through at least 7 mhz as demonstrated by their ability to conduct NTSC video signals without visible degradation. My conclusion is that it is the audiophile gear deliberately designed to sound different, the audiophiles wires, cd players, vacuum tube amplifiers which are flawed, sometimes seriously flawed. Then why do people buy them? Perhaps because in some cases their flaws mitigate other flaws such as the shrillness of their equally flawed loudspeakers and phonograph cartridges. In correcting linear (FR) disotortion we have far cheaper and more effective means available to us. It's up to high end equipment manufacturers to convince audiophiles not to use them and in that regard, they have largely succeeded.

[Carlspeak]

>>Ah, that is exactly what keeps the snake oil salesmen in

>>business. Even if there are "differences" who is

>to

>>say they are improvements?

>>

>>In the end it is in the ear, mind and pocketbook of the

>>beholder.

>>

>>Roy

>

>

>This issue of subjective relativism, one opinion being as

>valid as another has an appeal to our non judgemental

>egalitarian nature which we have been trained for in our

>modern society but I have a different take on it. As CD

>players, amplifiers, wires, perform strictly electrical

>functions they can and should be evaluated by purely

>electrical performance standards and compared to an ideal

>model of their function. In some cases this is actually easy

>to test in practice such as by substituting a shunt for a

>wire. The closer the wire in the circut sounds to the shunt,

>the better it is whether you prefer it or not.

So much for the romance of the audio hobby :-(

In comparing

>two CD player of two different eras, a 1 bit JVC player

>costing $200 purchased in 1991 and a $45 24 bit Toshiba DVD

>player purchased in 2006 using duplicate (factory made) discs

>exactly synchronized, I came to the conclusion that they were

>subjectively indistinguishable, surprisingly even in their

>output level. I concluded that both performed their functions

>subjectively perfectly. I have never been able to detect any

>audible difference between a $1 interconnect and a shunt which

>hardly surprised me since they are also flat from DC through

>at least 7 mhz as demonstrated by their ability to conduct

>NTSC video signals without visible degradation. My conclusion

>is that it is the audiophile gear deliberately designed to

>sound different, the audiophiles wires, cd players, vacuum

>tube amplifiers which are flawed, sometimes seriously flawed.

>Then why do people buy them? Perhaps because in some cases

>their flaws mitigate other flaws such as the shrillness of

>their equally flawed loudspeakers and phonograph cartridges.

>In correcting linear (FR) disotortion we have far cheaper and

>more effective means available to us. It's up to high end

>equipment manufacturers to convince audiophiles not to use

>them and in that regard, they have largely succeeded.

>

Here again we have but one data point demonstrated by one man's conclusion which is well taken and recorded.

Ahhh, but for me at least, the glass will aslways be half full!

BECAUSE.............

It's all about the music

Carl

Carl's Custom Loudspeakers

[Guest robotczar]

Thanks for the link, but this article doesn't make any sense to me. Biwiring doesn't do anything except add wire.

The article reveals itself as snake oil without having to discuss the reasons biwiring can't work. First, is says "sonic improvements" which should set off alarms. Accuracy is what is desired, not "improvements". That phrase indicates that the listener is making a completely subjective judgement (i.e., not referencing a standard for accuracy), which is affected by all kinds of factors having nothing to do with wires or sound. Another indication of less than rational commentary is the statement that, "The effects of bi-wiring are not subtle." Huge effects that cannot be heard by many (or any if we go by the blind testing) are very doubtful.

I guess this makes two data points.

[soundminded]

A theoretical case can be made for biwiring in some circumstances but it's not the usual one. And I want to make it clear that I don't advocte it, use it, have never tried it and certainly never measured it. Frankly I couldn't care less because I don't sell speaker wires but here's a thought that occurred to me the first time I considered the suggestion of bi wiring.

With speaker systems having a large back emf from the woofer, with a single speaker wire that voltage is applied along with the amplifier voltage directly to the midrange and tweeter crossover sections through the woofer crossover section. Depeding on many factors such as the high pass slope and frequency of the crossover network to the midrange driver or to the tweeter if it is a two way system, this might have some effect. This effect would be diminished (theoretically) using bi-wiring because the amplifier output stage which acts as a shunt to damp back emf will appear as a node between the resistance of the wire to the woofer crossover sections and the wire to the midrange and tweeter crossover sections.

It should be possible to measure this. If anyone goes to the trouble to devise and carry out such a test, please report it, I think it would be of some passing interest to some of us. As usual, anecdotal stories don't carry much currency with me as with most of those who have had enough experience in this hobby or profession to have been duped more than once in our lives.

[Carlspeak]

Below is a link to another article on the subject which supports both Vandersteen's and Soundminded's text regarding back EMF's effect on mid and tweeter sections of passive crossovers. I'd say 3 totally unaffiliated references claiming similar effects may by worth paying attention to.

Personaly, I have one amp for each channel and bi-wire via my A/B switch capabilitites from each amp to each speaker. That's my anecdotal opinion.

http://www.rdrop.com/~/twest/audio/index.html

It's all about the music

Carl

Carl's Custom Loudspeakers

[onplane]

>Below is a link to another article on the subject which

>supports both Vandersteen's and Soundminded's text regarding

>back EMF's effect on mid and tweeter sections of passive

>crossovers. I'd say 3 totally unaffiliated references claiming

>similar effects may by worth paying attention to.

>

>Personaly, I have one amp for each channel and bi-wire via my

>A/B switch capabilitites from each amp to each speaker. That's

>my anecdotal opinion.

>

>http://www.rdrop.com/~/twest/audio/index.html

>

>It's all about the music

>

>Carl

>Carl's Custom Loudspeakers

Carl, I haven't posted on this thread since Tom made it clear he felt that ideas like bi-wiring and bi-amping belong in "Mods, Tweaks and Upgrades" forum.

My feeling is neither are mods or tweaks or upgrades. The speakers remain unchanged except for the strap between T and 2, which was intended for the customer to remove. Further, AR speakers with 3 terminals are the exception rather than the rule. (I have never seen any speaker system besides AR's with 3 terminals.) Consequently, bi-amping AR's is totally different from all of the traditional 4 terminal systems and I believe should be discussed in this forum.

In any event, Carl, just wanted to make two comments on your post:

1. A/B switch for bi-wiring will work on some amps, but will NOT work on many. Problem is on many amps when you select both the A and B speaker sytems, the selector switch puts the speakers in series! This could be a dangerous arrangement with the 3 terminal AR's! In short, before anyone tries this on AR's they must be certain that their amp places the speakers in parallel.

2. Your comments about back EMF are interesting. I noticed that in both articles neither writer is recommending expensive speaker cables or expensive bi-wire cables. In fact, the whole idea behind the back EMF article is that some resistance exists in the run of speaker cable from the amp to the mids/tweeters. This "some resistance" indicates to me they are talking about modest speaker wire (aka zip cord).

Regards,

Jerry

[Carlspeak]

My feeling is neither are mods or tweaks or upgrades. The speakers remain unchanged except for the strap between T and 2, which was intended for the customer to remove. Further, AR speakers with 3 terminals are the exception rather than the rule. (I have never seen any speaker system besides AR's with 3 terminals.) Consequently, bi-amping AR's is totally different from all of the traditional 4 terminal systems and I believe should be discussed in this forum.

In any event, Carl, just wanted to make two comments on your post:

1. A/B switch for bi-wiring will work on some amps, but will NOT work on many. Problem is on many amps when you select both the A and B speaker sytems, the selector switch puts the speakers in series! This could be a dangerous arrangement with the 3 terminal AR's! In short, before anyone tries this on AR's they must be certain that their amp places the speakers in parallel.

2. Your comments about back EMF are interesting. I noticed that in both articles neither writer is recommending expensive speaker cables or expensive bi-wire cables. In fact, the whole idea behind the EMF article is that some resistance exists in the run of speaker cable from the amp to the mids/tweeters. This "some resistance" indicates to me they are talking about modest speaker wire (aka zip cord).>>

Thanks Jerry. My regular listening speakers are not AR's, so your point #1 above doesnt' affect me at least. I doubt very much AR's original intent of the 3 terminals was for bi-wiring, but, instead, give the user the option to have full range sound or just bass.

It's all about the music

Carl

Carl's Custom Loudspeakers

[Guest robotczar]

Thanks for the information. I haven't heard this back EMF argument before, but I find it slightly hard to believe as typical biwiring arrangements have all the drivers shorted to each other at the amp terminal. I don't think they 'see" back EMF any differently than in a non-biwire arrangement.

As for audio validity being established by two or three people having a similar opinions, I wouldn't put much stock in that idea. Lots and lots of audio craziness goes on (pucks anyone?) with more than a few people offering up support, and the high end press joining in. High end audio is rife with lots of opinions, I prefer some evidence and some logic from electrical engineers.

Subjectivity versus objectivity is a key point. If you want beautiful sound, tweak away and get "sonic improvments". AR was a company that stressed accuracy to a live reference as the goal. That goal is significantly more objective--a long way from everybody's opinion of pretty sound--but still open to personal opinion when it comes to speaker and speaker placement.

[kkantor]

Carl,

Questioning is a good thing. The problem is that audio won't get anywhere if we have to keep repeating research that has been already been adequately done. If ten or twenty posts on the internet are a reason to go back and question proven aspects of engineering, all sorts of fields are in big trouble! There are endless numbers of hobbyists who are convinced they are the first to think about this, that or the other thing. These people rarely take the time to do any research into prior art.

Every speaker company that I know of, at least ones large enough to have an engineer staff, investigated bi-wiring in the 70's and 80's. At AR, we found no bi-wiring benefits on any of our models. I've tested hundreds of speakers from many brands over the years. I've found exactly one that had the kind of crossover situation that could be effected by bi-wiring. Even in this case, the effect was very small.

Also, let me try to explain something:

"Back EMF" is an evocative term that makes it seem like something is going on that is over and above normal, linear circuit theory. This is simply not correct. In a speaker, back EMF is the SAME THING as reactive energy storage. It is completely described by the complex input impedance, and is included in the normal system model. In other words, there is no energy flow, current, voltage or anything else from a speaker that is any different from connecting a collection of resistors, inductors and capacitors. (I'm not counting the effect of physically pushing the drivers, but I am counting the effect of room reflections coming back.)

Just as there are many superb and well-educated scientists who don't have the talent to make good speakers, there are some really excellent speaker designers around who have an incomplete understanding of acoustics and physics.

-k

http://kkantor.spaces.live.com

www.kenkantor.com

[rrcrain]

I've read the bi-wiring articles in the past and those authors that stuck to pure math and physics concluded there is a theoretical advantage, but not enough to waste money on and definitely not enough to be heard by their ears.

I've tried bi-wiring, and simply put, it doesn't do a thing for me. Further, I've yet to personally meet a single soul who's tried it and claims it works, or was worth the money spent.

I've tried bi-amping without an active crossover, and it sounds different, not exactly better. We noticed a distinct disjointedness to the sound that took as much, or more away than the second amp gave.

I've tried bi-amping with an active crossover, and this I like. The crossover must be high quality and the crossover points absolutely must be set outside of the speakers crossover points. Interfere with the built in crossover and the result will not be pretty.

[soundminded]

>Thanks for the information. I haven't heard this back EMF

>argument before, but I find it slightly hard to believe as

>typical biwiring arrangements have all the drivers shorted to

>each other at the amp terminal. I don't think they 'see"

>back EMF any differently than in a non-biwire arrangement.

>

Back EMF is a real phenomenon. It is the result of the fact that kinetic energy in the moving mass of a speaker will cause the speaker coil to act as an electrical generator delivering current into whatever electrical load is connected to it whether it is the internal impedence of the amplifier output circuit in series with the resistance of the speaker wires or other drivers connected through crossover network elements. It is real, the question is whether or not it is so negligable as to be insignificant and therefore not worthy of consideration. IMO, in most cases that is likely the case. In acoustic suspension speakers, the woofer's moving mass is usually well damped mechanically (the function of the stuffing) and the energy is probably mostly dissipated this way. This may not be the case however in some ported designs with a large resonant bass peak. At or near the resonant frequency, electrical dissipation may be much more important and the damping factor of the amplifier and gage and length of the wires can play a role. To excite midrange or tweeter drivers, current due to the woofer's back EMF must not only get through its own crossover elements but theirs as well and they are in parallel with the much lower amplifier output impedence circuit. This is probably why the differences are almost always inaudible except in very rare and unusual cases.

Back EMF is very well known to those who work with rotary motors, especially large ones used to move heavy loads such as in cranes and elevators. Electrical braking supplemental to mechanical braking is accomplished by connecting a shunt across the armature (analogous to the voice coil) which dissipates the kinetic energy of the load by forcing the back EMF to dissipate current into a low value resistance converting it into heat.

Insofar as the room is concerned, the volume of air in even a small room is enormous compared to the volume of air moved by a loudspeaker system. The change in pressure on the front of the driver resulting from compressing the room's air will cause almost no additional force on the speaker, certainly much too small to affect its performance. Only by slot loading or horn loading the front of a speaker can you get it to work against a sufficiently significant mechanical load to change its mechanical and electrical properties. Therefore the advertising term "room loading" has no valid basis in fact.

[onplane]

>Carl,

>

>Also, let me try to explain something:

>

>"Back EMF" is an evocative term that makes it seem

>like something is going on that is over and above normal,

>linear circuit theory. This is simply not correct. In a

>speaker, back EMF is the SAME THING as reactive energy

>storage. It is completely described by the complex input

>impedance, and is included in the normal system model. In

>other words, there is no energy flow, current, voltage or

>anything else from a speaker that is any different from

>connecting a collection of resistors, inductors and

>capacitors. (I'm not counting the effect of physically

>pushing the drivers, but I am counting the effect of room

>reflections coming back.)

>

>Just as there are many superb and well-educated scientists who

>don't have the talent to make good speakers, there are some

>really excellent speaker designers around who have an

>incomplete understanding of acoustics and physics.

>

>-k

>

Ken, I'd have to side with soundminded on this one and question your logic here. The problem with linear circuit theory is that raw speakers are anything but ... linear!

Yes, in a way back EMF is similar to what happens in a coil, but it's not really the same. In a coil, current flow will cause the creation of a field and when that current starts to reduce, the field collapses on the coil and causes an induced current.

That field "collapsing" scenario certainly happens in a voice coil, but much more is going on. The voice coil is moving and when moving it's cutting lines of force and inducing a current flow … in the opposite direction.

Further confusing things is a coil will retain a constant inductance over a very wide frequency range. The inductance of loudspeaker’s voice coil, however, is frequency-dependent. In short, the inductance is going DOWN as frequency goes UP, and that the effective resistance of the voice coil goes UP as the frequency goes UP. Nothing linear at all about this!

Even complex models like the one below can’t adequately predict speaker behavior:

http://www.classicspeakerpages.net/dc/user_files/2222.jpg

Ken, out of curiosity what model do you folks use to predict speaker behavior?

Regards,

Jerry

[onplane]

>I've read the bi-wiring articles in the past and those

>authors that stuck to pure math and physics concluded there is

>a theoretical advantage, but not enough to waste money on and

>definitely not enough to be heard by their ears.

>

>I've tried bi-wiring, and simply put, it doesn't do a thing

>for me. Further, I've yet to personally meet a single soul

>who's tried it and claims it works, or was worth the money

>spent.

>

>I've tried bi-amping without an active crossover, and it

>sounds different, not exactly better. We noticed a distinct

>disjointedness to the sound that took as much, or more away

>than the second amp gave.

>

>I've tried bi-amping with an active crossover, and this I

>like. The crossover must be high quality and the crossover

>points absolutely must be set outside of the speakers

>crossover points. Interfere with the built in crossover and

>the result will not be pretty.

>

Hi, Richard!

I think we've had this discussion before, but as I understand it, you kept the passive networks in place AND used an active network between the pre-amp and the power amp.

You further set the active network’s xover points well above and below the passive network’s points to prevent starving the drivers for the frequencies they need.

Clearly, Richard, this scheme will work, but the active network is NOT selecting the frequency ranges for the drivers. With this scheme, the passive networks continue to do this job. What the active network is doing is DISCARDING unwanted frequencies and this CAN improve the resulting sound.

Theory behind this is that NO amplifier is perfect and all amplifiers have some level of IM distortion. IM distortion occurs in amplifiers whenever we amplify very low frequencies (fundamentals) at the same time that we amplify very high frequencies (harmonics). Richard, your scheme prevents the mixing of these diverse frequency ranges and the result will be LOWER IM distortion. Naturally, lower IM distortion will means a cleaner, clearer audio signal. My guess is the improvement you heard is primarily in the area of clarity.

Regards,

Jerry

[kkantor]

Well, this is a total waste of time, as far as I'm concerned. It's not a matter of voting. You are just plain wrong. Loudspeaker impedance is extremely well-characterized by a linear system model, up until clipping. It's really rather simple: cone momentum is converted by the driver's BL transformer into reactive impedance. Nothing more, nothing less. You can read Beranek or Novak or Olson or ... if you want to try and learn more about this.

I beg you to stop spreading technical disinformation. It's really hard for casual users to get proper technical information via the web. This kind of thread really doesn't help.

-k

www.kenkantor.com

http://kkantor.spaces.live.com

PS- I had the distinct pleasure of spending a couple of days travelling with Neville Thiele in China last week. A gentleman and a scholar. Perhaps I will ask him to drop by here to re-explain this stuff to you, as he seems to have developed much more patience with amateur stubborness than I have.

[onplane]

>Well, this is a total waste of time, as far as I'm concerned.

> It's not a matter of voting. You are just plain wrong.

>Loudspeaker impedance is extremely well-characterized by a

>linear system model, up until clipping. It's really rather

>simple: cone momentum is converted by the driver's BL

>transformer into reactive impedance. Nothing more, nothing

>less. You can read Beranek or Novak or Olson or ... if you

>want to try and learn more about this.

>

>I beg you to stop spreading technical disinformation. It's

>really hard for casual users to get proper technical

>information via the web. This kind of thread really doesn't

>help.

>

>-k

>

>www.kenkantor.com

>http://kkantor.spaces.live.com

>

>

>PS- I had the distinct pleasure of spending a couple of days

>travelling with Neville Thiele in China last week. A

>gentleman and a scholar. Perhaps I will ask him to drop by

>here to re-explain this stuff to you, as he seems to have

>developed much more patience with amateur stubborness than I

>have.

>

Ken, perhaps you should have this conversation with Dick Pierce. Dick was the technical of a driver manufacturer and measured 1000's upon 1000's of speakers. I think he understands both the electronics and the physics of drivers as well as anyone.

Further, if you'll have Mr. Theile review Dick's work, I’m certain that he’ll find little fault:

http://www.epanorama.net/documents/audio/s..._impedance.html

If he does have problems, I’m confident Dick will be happy to explain it to him and to you.

Regards,

Jerry

PS: I'm only conveying the best of the info on the web. I’m NOT making any of this up!

Lastly, Ken you sound pretty confident, but then again you sounded pretty confident when you wrote:

"Removing the pot entirely will yield a large, ugly resonant peak at the low end of the tweeter's response. Even running the pot wide will show this.

I'm not against bi-amping, and there are good reasons to replace the pot with fixed resistors. (Power handling, corrosion, etc.) However, it would seem that simply taking the pot out of the circuit will yield a response that is difficult to correct, and might even put the tweeter in some jeopardy at higher levels."

Naturally there is NO “ugly resonant peak”, because your model is woefully inadequate. If you think there is or should be one … find it!