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Acoustic Research Crossover Inductors (Classic)


RoyC

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You ought to be absolutely sure about the facts when you use words such as nonsense and misleading. Let me explain why I am so sure about this. I've been simulating and building systems with BSC for about 10 or 15 years. I know off the top of my head that 3mH for a 4 ohm woofer in a 3 way is the value for a crossover with BSC. This is the value that I start with before optimization in simulation software. I knew at a glance of the XO schematics, 3a, 11, LST, that they had BSC. It is absurd to be arguing otherwise. I also noted that I had to use the 1.9 mH value to get agreement in simulation with the very early documentation.

It is obvious to me that AR did indeed do 4pi measurements and design for flat response under those conditions. There are probably many reasons, the obvious ones are that such designs sound better and that reviewers measure, or have systems measured by independent labs under anechoic 4pi conditions. It is the industry standard. I have an AR LST review from High Fidelity who used the well known CBS Laboratories to test systems under anechoic 4pi conditions. The response does not show any droop from 500 Hz down to 100 Hz as would be expected if the system was designed for 2pi loading. Audio Magazine has also been using anechoic measurements, or corrected to 4pi anechoic, for as long as I can remember.

You yourself discuss AR's move from outdoor measurments to an anechoic chamber utilizing a LF calibration correction. These calibrations typically calibrate to 4pi because this is the intent of an anechoic chamber. There is further support in the AES literature that AR was using both 4pi and 2pi measurements in 1970. I've given this reference elsewhere on this forum.

You have the attitude that if you didn't know about something at AR it didn't happen. Were you ever employed by AR?

Your diagram above looks like a cut and paste of several AR documents.

Here is literature from AR indicating a 4pi measurement, you repeatedly state your erroneous position when the facts are as plain as can be. Note the red oval and arrow:

http://members.aol.com/basconsultants/ARDOC.jpg

Pete B.

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I wondered if anyone would catch that, yes that is an error in the document - I am certain that it is a 4pi measurement. Both types of measurements, 2pi and 4pi can be seen in Allison and Berkovitz's "The Sound Field in Home Listening Rooms", JAES July/August 1972, Figures 6 and 8 respectively.

Please note that while the date of the AES article is 1972, the paper was presented on October 12, 1970 at the 39th Convention of the Audio Engineering Society, New York. Obviously the research was done prior to presenting the paper around the time of the change from the #7 to #9 inductor. Clearly, AR was doing 2pi and 4pi measurements given that they're shown in the publication.

Interesting to note that the 4pi measurements show LF droop that is expected with the #7 inductor.

Pete B.

>Look at the two words that follow your red-circled 360

>degrees, in the parentheses: a hemisphere. So is it supposed

>to be 180 degrees, after all?

>

>

>Bob

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>I wondered if anyone would catch that, yes that is an error in the document - I am certain that it is a 4pi measurement.<

I just went away confused.

Has anyone ever found a #7 coil that measured 2.85mH?

Bret

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>>I wondered if anyone would catch that, yes that is an

>error in the document - I am certain that it is a 4pi

>measurement.<

>

>I just went away confused.

>

>Has anyone ever found a #7 coil that measured 2.85mH?

>

>Bret

>>I wondered if anyone would catch that, yes that is an

>error in the document - I am certain that it is a 4pi

>measurement.<

>

>I just went away confused.

>

>Has anyone ever found a #7 coil that measured 2.85mH?

>

>Bret

Not sure what your confused about. I read that AR sales literature several times and we tend to want to believe what comes from an authority so it looked OK until I looked specifically for full vs. half space.

Just to be clear:

360 degrees = full space = 4pi

180 degrees = half space = 2pi

That AR document states 360 degrees, then in parenthesis half space.

The clarification in parenthesis is wrong because half space is not the same as 360 degrees. It seems that AR people were having a difficult time adjusting to the new 360 degree measurements and slipped back to the old thinking.

I wrote above and let me clarify:

"Interesting to note that the 4pi measurements show LF droop that is expected with the #7 inductor."

I was referring to the 4pi measurements in the AES article.

The 4pi measurements in the sales literature above, do not show droop because this was the new 3a design with a #9 inductor and ceramic magnet woofer as I see it. I'm told by an AR expert probably from 1970 which supports this theory.

Pete B.

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>Not sure what your confused about.<

The 360 degree hemisphere. That's all.

Loving for many years, and now-owning, 10pi's, I'm not the least confused about what the switches are for, or why. But a 4pi hemispherical measurement? That'll confuse me every time.

Bret

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>Pete -

>

>It's back to geometry for us both.

>

>A 360 degree solid angle is a hemisphere - 2pi. It's a 2pi

>measurement they are describing.

>

>Bret

Speak for yourself, and do some research before you post:

"There was also a noticeable loss of bass compared to the listening room. First, the speakers could not be located against a wall or a floor. As a result, the speakers were effectively radiating into a 360-degree solid angle. There was no room gain. Second, there were no standing waves above 65Hz, and reflections were reduced below that frequency."

From:

http://www.roger-russell.com/cham2pg.htm

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>You ought to be absolutely sure about the facts when you use

>words such as nonsense and misleading. Let me explain why I

>am so sure about this. I've been simulating and building

>systems with BSC for about 10 or 15 years. I know off the top

>of my head that 3mH for a 4 ohm woofer in a 3 way is the value

>for a crossover with BSC. This is the value that I start with

>before optimization in simulation software. I knew at a

>glance of the XO schematics, 3a, 11, LST, that they had BSC.

>It is absurd to be arguing otherwise. I also noted that I had

>to use the 1.9 mH value to get agreement in simulation with

>the very early documentation.

Pete, Pete, Pete. I’m sure you’re a nice guy, but I really think you assume too much. Might it be a beautiful hypothesis slain by an ugly fact? There was *no* BSC designed into the AR-3a crossover; no 360 degree solid-angle measurements. You just think there were. This is why I refer to your statements as being nonsense -- which they frequently are -- and misleading. I’m sure you mean well, but sometimes “the road to hell is paved with good intentions.”

>

>It is obvious to me that AR did indeed do 4pi measurements and

>design for flat response under those conditions. There are

>probably many reasons, the obvious ones are that such designs

>sound better and that reviewers measure, or have systems

>measured by independent labs under anechoic 4pi conditions. It

>is the industry standard. I have an AR LST review from High

>Fidelity who used the well known CBS Laboratories to test

>systems under anechoic 4pi conditions. The response does not

>show any droop from 500 Hz down to 100 Hz as would be expected

>if the system was designed for 2pi loading. Audio Magazine

>has also been using anechoic measurements, or corrected to 4pi

>anechoic, for as long as I can remember.

>

NOPE. If you go to the CBS Labs full report No 6017-040-1 on the AR-LST, p.3, following is said about the anechoic testing: “Total acoustic power output vs. frequency response above 500 Hz., Fig. 1. Below 500 Hz, the woofer anechoic curve in Fig. 3 applies for 2 Pi radiation angle.” The speaker output below 500 Hz does not show any droop because it was measured looking into 180-degree solid angle, not 360 degrees.

>

>You yourself discuss AR's move from outdoor measurments to an

>anechoic chamber utilizing a LF calibration correction. These

>calibrations typically calibrate to 4pi because this is the

>intent of an anechoic chamber. There is further support in

>the AES literature that AR was using both 4pi and 2pi

>measurements in 1970. I've given this reference elsewhere on

>this forum.

>

NOPE. There is nothing that says an anechoic chamber has to be used in full space; the intent of an anechoic chamber is to be echo-free. It can be used for other than full-space measurements, which is what AR did. It is also well known that the absolute output of a speaker system is influenced by the solid angle of the space into which it radiates, so reducing the solid angle in half doubles the amount of energy radiated at low frequencies. A high-fidelity loudspeaker system would almost never be used in a location that represented a 4-Pi steradians (360 degrees, “full space,” or a full sphere) solid angle; that would correspond to a position below the center of the ceiling and half the distance between the floor and ceiling. It was usually (at least in the early days of audio) always close to one wall, and usually fairly close to another wall or the floor as well. Thus, the normal radiation angle is 2 Pi steradians (180 degrees, “half space,” or a hemisphere) solid angle. To assess its performance by measuring into a 4 Pi (a conventional anechoic chamber) solid angle, without taking into account this difference, is to be mislead.

At AR, the large anechoic chamber had absorbent wedges on only five interior surfaces. The sixth was made as smooth as possible. The speaker to be tested was put on a flat baffle that sat flush with the inside of the smooth chamber wall; for woofers or complete system, the front of the cabinet is fitted flush with the inside surface. In this way AR achieved a true 2-Pi radiation angle for all tests: the wall of the chamber itself provided an infinite baffle large enough for any conceivable purpose. But since AR’s large anechoic chamber was anechoic to just below 200 Hz, the outdoor measurement was used to get the true 2-Pi response below that frequency. AR made a calibration curve based on the outdoor 2-Pi curve for a specific speaker, and then compensated for the known calibration curve of the chamber. It was easy to measure the performance of each speaker of a system individually without having to make allowances or corrections for the baffle. A final advantage is that these measurement conditions conformed to the RETMA Standard SE-103 and ASA Stantard S1.5, 1963.

>

>Your diagram above looks like a cut and paste of several AR

>documents.

>

Thanks for the insult. What I did was to take a large blue-line drawing, approximately 24 x 36 or so, and I tried to bring it down as much as possible. I paraphrased the “legend” into the response graph. But just to show you that it was 100% factual, here is the legend itself and the other parts of the drawing. I was simply trying to consolidate that information without having to show several different images.

http://www.classicspeakerpages.net/dc/user_files/967.jpg

Dwg. 206008 AR-12W Measurement Conditions Legend

http://www.classicspeakerpages.net/dc/user_files/968.jpg

Dwg. 206008 Inscription

http://www.classicspeakerpages.net/dc/user_files/969.jpg

Dwg. 206008 AR-12W 2-Pi Response Standard

>

>Here is literature from AR indicating a 4pi measurement, you

>repeatedly state your erroneous position when the facts are as

>plain as can be. Note the red oval and arrow:

>Pete B.

NOPE. I do see your red arrow, but there is a mistake in the printed brochure that states, “360-degree solid angle (a hemisphere).” The ad writer was apparently confused. Might that have been you?

--Tom Tyson

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Pete - I made the mistake of not doing my research before I posted the first time. Found it hard to believe that they'd let the lit go out like that so continued my quest. We'll have to let Descartes speak for himself. . . except, of course, he's dead.

Now before either of us gets our noses out of joint, ALL I was saying was that the literature that uses "360 degree solid angle" and "hemisphere" interchangably isn't wrong **in its use of the terms interchangably**.

From page 4 of 14:

http://www.optics.arizona.edu/Palmer/rpfaq/rpfaq.pdf

"If we divide the surface area of a sphere by the square of it's radius, we find that there are [4pi] steradians of solid angle in a sphere. One hemisphere has [2pi] steradians."

Or:

http://www.unc.edu/~rowlett/units/dictH.html

"hemisphere

a traditional unit of solid angle equal to 1/2 sphere, 2pi steradians, or about 20 626.48 square degrees."

OR:

http://www.unc.edu/~rowlett/units/dictS.html

"sphere

the traditional unit of solid angle measure, divided into 4(pi) steradians (see below). There are also 129 600/(pi) = 41 252.96 square degrees in a sphere. This unit is also called the spat (see above).

spherical degree

a unit of relative surface area for spheres, equal to 1/720 the total surface area or pi·R2/180, where R is the radius of the sphere. Thinking in terms of the Earth's surface, this is the area of the region in one hemisphere (northern or southern) bounded by the equator and two meridians of longitude one degree apart."

And also:

"steradian (sr)

the standard unit of solid angle measure in mathematics. Just as there are 2pi radians in a circle, there are 4pi steradians in a sphere."

OR:

http://www.neubert.net/DESCarte.html

The above is actually a really cool explanation of how a sphere gets 720 degrees in it with lots of little mouse-over spheres subdivided to find "Descartes' Law of Closure Deficit" the hard way.

And while we're on the subject of Renee, Python fans might enjoy the following link:

http://www.mtholyoke.edu/~ebarnes/python/bruces'-song.htm

Now Pete, before either of us gets our noses out of joint, ALL I was saying was that the literature that uses "360 degree solid angle" and "hemisphere" interchangably isn't wrong. They contend that what they are DESCRIBING is a 2pi measurement, not a 4pi. **I** am contending **NOTHING** about the measurements. ***ONLY*** the words.

I'm not saying diddley about your measurements, or misreadings, or simulations, or tests, or your 1970s AR buddy, or any mistake you might think I'm accusing you of. I'm not accusing you of ANYTHING.

I'm *only* referring to whether the term was used incorrectly in the literature. (or conversely if I were confused about what "Solid Angle 360 degrees" was - which I was - it's a hemisphere; just like the lit says it is) AR was *not* having a hard time getting its terms straight or being the least confused. Solid angle 360 degrees = 2pi. Solid angle 720 degrees = 4pi.

Geewhiz, Pete. Calm yourself. It's not that big of a deal. If I ever studied "solid angle" measurements in trig or geometry, I long forgot them.

I think you jumped me rather unfairly, man. You were never attacked.

Bret

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>I do see your red arrow, but there is a mistake in the printed brochure that states, “360-degree solid angle (a hemisphere).” The ad writer was apparently confused.<

Evidently the ad writer wasn't confused, Tom. We (read: at least *I* and perhaps several others) did not know how to interpret "solid angle 360 degrees" which, as it turns-out really does mean the same thing as "hemisphere," just as the literature says. This supports everything you've said about 2pi measurements. (please see my last response to Pete as I have spent the evening verifying this - at least to my own satisfaction)

The ad writer was impressing us with his math skills, or it was dictated to him by someone who didn't know how misleading that sounded. Or maybe everyone that read it said, "HUH?" and that's why an editor insisted on the parenthetical clarification.

Wasn't it Andy Grove that said something like; we judge how well we communicate, not by how well we say something but by how well we are understood? Well, that statement was unnecessarily awful.

Bret

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No need for the lecture, and drop the personal attacks will you, just the facts.

I don't like to do this, but I think it's reasonable to say that you have pushed me. You write with regard to me:

"This is why I refer to your statements as being nonsense -- which they frequently are -- and misleading."

I have to wonder if you are annoyed about your own mistakes and are projecting them on me.

I've not been keeping score here as I prefer to have a pleasant discussion, but you seem to be looking for a fight. I also sense that certain people here seem to see everything as a contest, who's the king of the hill, rather than research. I enjoy the research. Are you annoyed about the picture I showed you of a black anodized voice coil that you *thought* didn't exist. Or about using non-anodized aluminum formers, that you thought was never done. Or is it that the woofer changed when you claimed it did not, remember Ken and his group measured ~105 for the older drivers and ~68 g for the newer, which I confirmed with a 67.5 g measurement. I've noticed a few times that you insisted that a #7 coil was never used, yet forum members continue to document more and more. I don't really care one way or the other. I've simply supported that theory with my simulations, there is much evidence that the #7 coil was used. Is this an old pissing contest of yours? Annoyed that you were wrong about the #7 coil?

Yes I was wrong about the Bl of the Tonegen, but I stated that it was a theory, and it did not seem logical to change the moving mass but they did - I did not expect it. I don't have a problem when a theory is verified and something else is found, the difference came out in the end and that is what's important. When your errors were demonstrated in the past I did not exaggerate them or shove them in your face.

I've already stated that the term BSC was not used in those times, and let me also add that 3 mH does not fully correct for a 4pi environment, it offers somewhat less than the full correction.

I am fully aware that both 2pi and 4pi anechoic measurements can be and were made in the AR chamber. The methodology was reported in the AES article and I stated that both can and were made, this is no surprise.

You, on the other hand, repeatedly insist that only 2pi measurements were made and I'm going to disprove this in a moment by scanning the figures out of the AES article, and they will speak for themselves. This alone will prove that you were not aware of everything that went on at AR, it further shows that you've not read the literature.

I'll scan the AES article tomorrow, and the figures will speak for themselves.

Pete B.

>>You ought to be absolutely sure about the facts when you

>use

>>words such as nonsense and misleading. Let me explain why

>I

>>am so sure about this. I've been simulating and building

>>systems with BSC for about 10 or 15 years. I know off the

>top

>>of my head that 3mH for a 4 ohm woofer in a 3 way is the

>value

>>for a crossover with BSC. This is the value that I start

>with

>>before optimization in simulation software. I knew at a

>>glance of the XO schematics, 3a, 11, LST, that they had

>BSC.

>>It is absurd to be arguing otherwise. I also noted that I

>had

>>to use the 1.9 mH value to get agreement in simulation

>with

>>the very early documentation.

>

>Pete, Pete, Pete. I’m sure you’re a nice guy, but I really

>think you assume too much. Might it be a beautiful hypothesis

>slain by an ugly fact? There was *no* BSC designed into the

>AR-3a crossover; no 360 degree solid-angle measurements. You

>just think there were. This is why I refer to your statements

>as being nonsense -- which they frequently are -- and

>misleading. I’m sure you mean well, but sometimes “the road

>to hell is paved with good intentions.”

>

>>

>>It is obvious to me that AR did indeed do 4pi measurements

>and

>>design for flat response under those conditions. There

>are

>>probably many reasons, the obvious ones are that such

>designs

>>sound better and that reviewers measure, or have systems

>>measured by independent labs under anechoic 4pi

>conditions. It

>>is the industry standard. I have an AR LST review from

>High

>>Fidelity who used the well known CBS Laboratories to test

>>systems under anechoic 4pi conditions. The response does

>not

>>show any droop from 500 Hz down to 100 Hz as would be

>expected

>>if the system was designed for 2pi loading. Audio

>Magazine

>>has also been using anechoic measurements, or corrected to

>4pi

>>anechoic, for as long as I can remember.

>>

>

>NOPE. If you go to the CBS Labs full report No 6017-040-1 on

>the AR-LST, p.3, following is said about the anechoic

>testing: “Total acoustic power output vs. frequency response

>above 500 Hz., Fig. 1. Below 500 Hz, the woofer anechoic

>curve in Fig. 3 applies for 2 Pi radiation angle.” The

>speaker output below 500 Hz does not show any droop because it

>was measured looking into 180-degree solid angle, not 360

>degrees.

>

>>

>>You yourself discuss AR's move from outdoor measurments to

>an

>>anechoic chamber utilizing a LF calibration correction.

>These

>>calibrations typically calibrate to 4pi because this is

>the

>>intent of an anechoic chamber. There is further support

>in

>>the AES literature that AR was using both 4pi and 2pi

>>measurements in 1970. I've given this reference elsewhere

>on

>>this forum.

>>

>

>NOPE. There is nothing that says an anechoic chamber has to

>be used in full space; the intent of an anechoic chamber is to

>be echo-free. It can be used for other than full-space

>measurements, which is what AR did. It is also well known

>that the absolute output of a speaker system is influenced by

>the solid angle of the space into which it radiates, so

>reducing the solid angle in half doubles the amount of energy

>radiated at low frequencies. A high-fidelity loudspeaker

>system would almost never be used in a location that

>represented a 4-Pi steradians (360 degrees, “full space,” or a

>full sphere) solid angle; that would correspond to a position

>below the center of the ceiling and half the distance between

>the floor and ceiling. It was usually (at least in the early

>days of audio) always close to one wall, and usually fairly

>close to another wall or the floor as well. Thus, the normal

>radiation angle is 2 Pi steradians (180 degrees, “half space,”

>or a hemisphere) solid angle. To assess its performance by

>measuring into a 4 Pi (a conventional anechoic chamber) solid

>angle, without taking into account this difference, is to be

>mislead.

>

>At AR, the large anechoic chamber had absorbent wedges on only

>five interior surfaces. The sixth was made as smooth as

>possible. The speaker to be tested was put on a flat baffle

>that sat flush with the inside of the smooth chamber wall; for

>woofers or complete system, the front of the cabinet is fitted

>flush with the inside surface. In this way AR achieved a true

>2-Pi radiation angle for all tests: the wall of the chamber

>itself provided an infinite baffle large enough for any

>conceivable purpose. But since AR’s large anechoic chamber

>was anechoic to just below 200 Hz, the outdoor measurement was

>used to get the true 2-Pi response below that frequency. AR

>made a calibration curve based on the outdoor 2-Pi curve for a

>specific speaker, and then compensated for the known

>calibration curve of the chamber. It was easy to measure the

>performance of each speaker of a system individually without

>having to make allowances or corrections for the baffle. A

>final advantage is that these measurement conditions conformed

>to the RETMA Standard SE-103 and ASA Stantard S1.5, 1963.

>

>>

>>Your diagram above looks like a cut and paste of several

>AR

>>documents.

>>

>

>Thanks for the insult. What I did was to take a large

>blue-line drawing, approximately 24 x 36 or so, and I tried to

>bring it down as much as possible. I paraphrased the “legend”

>into the response graph. But just to show you that it was

>100% factual, here is the legend itself and the other parts of

>the drawing. I was simply trying to consolidate that

>information without having to show several different images.

>>

>>

>>Here is literature from AR indicating a 4pi measurement,

>you

>>repeatedly state your erroneous position when the facts

>are as

>>plain as can be. Note the red oval and arrow:

>>Pete B.

>

>NOPE. I do see your red arrow, but there is a mistake in the

>printed brochure that states, “360-degree solid angle (a

>hemisphere).” The ad writer was apparently confused. Might

>that have been you?

>

>--Tom Tyson

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Bret,

I'm not sure what your trying to say, but this quote from your post is true and agrees with what I stated:

"If we divide the surface area of a sphere by the square of it's radius, we find that there are <4pi> steradians of solid angle in a sphere. One hemisphere has <2pi> steradians."

If the convention in acoustical measurement is different from mathematics, and I'm not saying that it is, it is probably because we think of looking at a 2d polar plot of a systems response where 180 is half space, and 360 is full space. This is the convention that I know and most other professionals use. See the reference to an anechoic chamber that I gave.

When I said do your research perhaps I should have said as it applies to this subject. Your going to have to find a reference to acoustical measurement to change my thinking. Otherwise I have no interest in continuing this, it is not productive.

Pete B.

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quotation

"""The Classic Speaker Pages and Civility"

I really do not want to have to exert "big brother" authority in these forums, but will if I have to.

Personal attacks and flame wars are not acceptable on The Classic Speaker Pages. I understand flame wars have become a tradition on lots of audio sites and newsgroups, but I won't accept them here - the content on this website, contributed by visitors, is too unique and valuable.

I need everyone to moderate themselves. Please take the higher road if you think you have been slighted, and chalk it up to agreeing to disagree and the nature of Internet communication.

I have been receiving email about how some threads have devolved and become very aggressive. I don't have time to keep on top of all the threads, and the time I do have I would prefer be spent on updating content and fixing bugs.

Hopefully this is the last time I have to post something like this. Again, I don't want to have to delete threads and revoke posting access, but I will if I need to - if simply to reduce the time I spend dealing with complaints.

Mark ""

HOPE SOMEONE WILL UNDERSTAND!

William

>You ought to be absolutely sure about the facts when you use

>words such as nonsense and misleading. Let me explain why I

>am so sure about this. I've been simulating and building

>systems with BSC for about 10 or 15 years. I know off the top

>of my head that 3mH for a 4 ohm woofer in a 3 way is the value

>for a crossover with BSC. This is the value that I start with

>before optimization in simulation software. I knew at a

>glance of the XO schematics, 3a, 11, LST, that they had BSC.

>It is absurd to be arguing otherwise. I also noted that I had

>to use the 1.9 mH value to get agreement in simulation with

>the very early documentation.

>

>It is obvious to me that AR did indeed do 4pi measurements and

>design for flat response under those conditions. There are

>probably many reasons, the obvious ones are that such designs

>sound better and that reviewers measure, or have systems

>measured by independent labs under anechoic 4pi conditions. It

>is the industry standard. I have an AR LST review from High

>Fidelity who used the well known CBS Laboratories to test

>systems under anechoic 4pi conditions. The response does not

>show any droop from 500 Hz down to 100 Hz as would be expected

>if the system was designed for 2pi loading. Audio Magazine

>has also been using anechoic measurements, or corrected to 4pi

>anechoic, for as long as I can remember.

>

>You yourself discuss AR's move from outdoor measurments to an

>anechoic chamber utilizing a LF calibration correction. These

>calibrations typically calibrate to 4pi because this is the

>intent of an anechoic chamber. There is further support in

>the AES literature that AR was using both 4pi and 2pi

>measurements in 1970. I've given this reference elsewhere on

>this forum.

>You have the attitude that if you didn't know about something

>at AR it didn't happen. Were you ever employed by AR?

>

>Your diagram above looks like a cut and paste of several AR

>documents.

>Here is literature from AR indicating a 4pi measurement, you

>repeatedly state your erroneous position when the facts are as

>plain as can be. Note the red oval and arrow:

>http://members.aol.com/basconsultants/ARDOC.jpg

>

>Pete B.

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Everyone has their own set of values and standard.

But if we just insist on our own points of view, we would create conflicts.

We should judge on the facts, rather than the people.

Try to put yourself in other people¡¦s shoes,

respect others and communicate more, we would then live in harmony.

Social harmony builds on respect and understanding

William

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Hi Pete,

>it is not productive<

Unfortunately it isn't. But it should be. And it can be. I think you and everyone else that's bothered to read what I've written sees very well what it is I was reporting.

We all, every single one of us, misinterpreted the verbiage because some archane mathematics jargon was used. I think you know you did it, too. (the evidence is on the board, I'm not making it up)

I think you'd like to send me off on a wild goose chase for homework and just forget the whole thing. I think you clearly see exactly what I was saying and unless we slip into another dimension where math works differently, you see that the literature is right and you see that I found an explanation for what at first looked like an error. There was no error in that AR literature. Period. The end. Over and out. No use arguing with me when Decartes is right.

If you turn your back on this, and continue to assert a thing you could see is wrong if you only looked . . .

You have used the statements in the literature in question to support a 4pi position when in fact the literature describes (badly) a 2pi measurement. I agree that the resultant graph seems odd under the circumstances, but I can't change what it says just because I think what it says doesn't make sense.

We have a bonafide mystery here with these inductors. The pursuit of an explanation is fascinating, the group dynamic is fascinating, I'm ready to "get to the bottom" of it, and the ultimate answer could be very, very educational (in a historical way).

I am amazed and happy that we have had Edgar Villchur and Roy Allison weigh-in. That means a lot to me that they'd care enough about US to respond. I'm really excited by all the work done by John and Roy. I think it is really, really great that Tom would take so much of his time to find all this documentation and provide us all with so much stuff to use as clues. And I think your going about it from the opposite end is interesting. I share your enthusiasm for "why?"

But if any of us asserts a non-factual position as support for our best guess as to how and why this happened, then it deteriorates into a yell-fest and we will never get anywhere.

I would like to think that the hours I spent trying to comprehend what a "360 degree solid angle" is and finally seeing that it actually is a hemisphere, a 2pi radiation pattern, and then providing link after link to proof of its truth would be met with a little more appreciation and respect.

Everyone can easily see how the interpretation error was made.

Bret

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Pete,

Let me say that I feel that our arguments seem to be going nowhere and are unproductive. I think it is in the best interest of this forum to discontinue debating this subject, so I will decline any comments going forward.

--Tom Tyson

>

>I don't like to do this, but I think it's reasonable to say

>that you have pushed me. You write with regard to me:

>"This is why I refer to your statements as being nonsense

>-- which they frequently are -- and misleading."

>I have to wonder if you are annoyed about your own mistakes

>and are projecting them on me.

>I've not been keeping score here as I prefer to have a

>pleasant discussion, but you seem to be looking for a fight.

>I also sense that certain people here seem to see everything

>as a contest, who's the king of the hill, rather than

>research. I enjoy the research. Are you annoyed about the

>picture I showed you of a black anodized voice coil that you

>*thought* didn't exist. Or about using non-anodized aluminum

>formers, that you thought was never done. Or is it that the

>woofer changed when you claimed it did not, remember Ken and

>his group measured ~105 for the older drivers and ~68 g for

>the newer, which I confirmed with a 67.5 g measurement. I've

>noticed a few times that you insisted that a #7 coil was never

>used, yet forum members continue to document more and more. I

>don't really care one way or the other. I've simply supported

>that theory with my simulations, there is much evidence that

>the #7 coil was used. Is this an old pissing contest of

>yours? Annoyed that you were wrong about the #7 coil?

>Yes I was wrong about the Bl of the Tonegen, but I stated that

>it was a theory, and it did not seem logical to change the

>moving mass but they did - I did not expect it. I don't have

>a problem when a theory is verified and something else is

>found, the difference came out in the end and that is what's

>important. When your errors were demonstrated in the past I

>did not exaggerate them or shove them in your face.

>

>Pete B.

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>Can you image how a speaker -- designed with BSC for flat response into 360 degree radiation -- would sound if that speaker were moved back and put in a bookshelf against the wall?<

I can attest that if you turn a 10pi to 4pi and stick it against the wall, you can't stay in the room with it.

Bret

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  • 4 weeks later...

>You, on the other hand, repeatedly insist that only 2pi

>measurements were made and I'm going to disprove this in a

>moment by scanning the figures out of the AES article, and

>they will speak for themselves. This alone will prove that

>you were not aware of everything that went on at AR, it

>further shows that you've not read the literature.

>

>I'll scan the AES article tomorrow, and the figures will speak

>for themselves.

>

>Pete B.

Not to open this up again, hopefully to finish it:

http://www.classicspeakerpages.net/dc/dcbo..._id=8445&page=2

Pete B.

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