Iconic Mfg. Co. to Exhibit @ Great Plains AudioFest in Tulsa 4/29-5/1!

[Todd W. White]

Hello Friends!

I am pleased to announce that Iconic Mfg. Co. (http://www.iconicspkrs.com/) will be exhibiting at the

http://www.greatplainsaudiofest.com/Great_Plains_Audiofest_Banner.jpg

in Tulsa April 29 - May 1, 2005!

More information about the GPAF can be found here:

GREAT PLAINS AUDIOFEST (http://www.greatplainsaudiofest.com/)

We will be demonstrating the STONEHENGE V SYSTEM that uses the newly re-designed ICONIC MODEL 704-8A COMPOUND LOUDSPEAKER!!!

In addition, we will be showing the several Iconic drivers, horns, and woofers (one of which is a BRAND NEW DESIGN), and some croosovers!

If you are or will be in the NE Oklahoma area on those dates, come by and see us!

[Todd W. White]

Hello friends,

Here are some pic's of Iconic's demo room at the Great Plains AudioFest in Tulsa (April 30, 2005):

1. Here's a view from the hallway (we were right in front of the elevator's):


http://www.iconicspkrs.com/old_images/GPAF_05/DemoRoom_1.jpg

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2. Here's a view from the far side of the room. The STONEHENGE V's were our showcase items:

http://www.iconicspkrs.com/old_images/GPAF_05/DemoRoom_2.jpg
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3. Here's another view of the demo table (kind of dark - sorry):

http://www.iconicspkrs.com/old_images/GPAF_05/DemoRoom_3.jpg
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4. A closer view of one of the STONEHENGE V systems (also kind of dark):

http://www.iconicspkrs.com/old_images/GPAF_05/DemoRoom_4.jpg
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5. A close-up of some of the static items we displayed. In the far right foreground is the ICONIC MODEL 704-8A with it's newly re-designed - and much improved - magnetic structure. The far right top unit is a Model 127-8A 12" direct radiator woofer. To it's left at the top is the Model 168-8A 16" Hi-Fidelity Woofer, and to the left front is a Model 145-8A Large Format Compression Driver with a Pascalite diaphragm. In the far left top corner is the Model 165-8G 16" Bass Horn Driver. Oh - and that's an Altec Model 711A FM Receiver from 1965 powering the Stonehenge V's - everyone loved it, and how NICE it sounded!:

http://www.iconicspkrs.com/old_images/GPAF_05/DemoRoom_5.jpg
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6. Another shot from the far end of the demo area. Note the Ella triode (tube) amp we tested (wonderful!):

http://www.iconicspkrs.com/old_images/GPAF_05/DemoRoom_6.jpg
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The STONEHENGE V's sounded EXCELLENT - very transparent and effortless in their ability to reproduce even the slightest nuances in the program material!

"The Bass Is Back!"

When playing the 4th cut of the soundtrack from "Star Trek - The Motion Picture", you could FEEL the 52" bass drum as the percussionist played it the Jerry Goldsmith score! Whenever anyone heard it, their eyes would get wide and a big smile would come upon their face - it was impressive!

My sons and a friend went around for about 3 hours looking and listening to the systems and the comments from the attendees. According to their reports, most everyone thought the Stonehenge V's with their 704-8A's were the best sounding speakers there.

We had a good time and met a lot of nice people, and are looking forward to the next show - perhaps the Chicago Horn Club and/or the Rocky Mtn. AudioFest in Denver.

[spkrman57]

Do you have any GP 399 drivers you can post photo to on this forum??? I have the drivers and don't have any way to post photos as my PC is nearly shot and dead.

Some members would like to see detailed photos of the 399!!!

Thanks, Ron

PS: Your website did not show any pics of that driver. I got them from Bill at GP
They are nice sounding 1.4" drivers, running them on 311-60 horns until I
find some nice wooden tractix horns that won't cripple my financial
situation.

[Todd W. White]

I'll be making new photo's of the 399 shortly. E-mail me directly and I'll send them when they're ready.

Incidentally - the website is being revamped and updated this week: we plan to have everything finished by this time next Monday.

[spkrman57]

Would be nice if you could post on this forum as I don't have a properly operating "photo-shop" to post here on the forum.

There are some folks who would like to see what I have and my only pics with them are hard to see and on another forum.

With Bill being the only one putting out larger compression drivers(new construction) that don't break the bank acct, it might prove worthwhile to post pics here!!!

Thanks, Ron

[Mr. Widget]

For those of us not quite as immersed in Altec as yourself could you give us a bit more info on your drivers. For example is 704-8A your designation for the reincarnation of the 604 series or was there a 704 produced? Is that a plastic Mantaray horn or something else?

I believe you have discussed this before, but are these components using original Altec tooling or have you made new tools based on original production parts? Where are you producing these components?

Glad to hear they are sounding good, those drivers are looking good too!

Widget

[spkrman57]

Are you referring to a reference list to the older Altec line of drivers with a euivalent Iconic model nr.

I think that would be very helpful to most of us who would be interested in Iconic products. But without knowing what they are(referenced to the older Altec models), I am reluctant to open my wallet right away.

I will say that if Bill at GP supplies Iconic with drivers, hard to go wrong.

I have bought from GP: pair of 416C's/902B's/399's (modern day 288K)

I am very happy with the craftmanship and Bill is very helpful at answering questions referring to application.

Todd, I apologize in advance if I am stepping on your toes and hijacking your thread. If I am out of line, just say so!!!!

Ron

[Don McRitchie]

I am curious about the changes to the magnet structure on the 704. Can you elaborate?

[Todd W. White]

The Iconic Model 704-8A Compound Loudspeaker is both a serious advancement forward and a reaching back into the glory years - the result is a two-way loudspeaker system that has the advantages of modern materials and methods of manufacture coupled with the performance of the 604-8G and 604-8H. During the years EV owned Altec Lansing (after the move to OKC), they forced Altec to standardize on a few magnets, rather than the large number Altec was used to using (they were particular about choosing just the right magent for the speaker they were designing - not so at EV). The early, Anaheim K's were actually quite good - almost, if not equally, as good as the "H"....but the change to a different magnet hurt the K a lot.

In the case of the 604-8K, they ended up using the magnet that EV had forced Altec to use on the 515-G series, which was much larger than the earlier one used on the "K" (it's also the same magnet EV was using on the DH-1A compression driver, if I'm not mistaken). This increased the flux density in the gap, but it also made the" "K" much more efficient - especially in the mid-band. The apparent result to the human ear was that the 604-8K didn't have much bass response, when, in reality, it hadn't changed - only the mid-band came up, and when it did, it created the perception that the "K" was "bass shy".

When reviewing the performance of the 704-8A prototype for us, Jerry Hubbard discovered this problem, and designed new metal top and bottom plates to compensate for the larger magnet and get the unruly mid-band back under control.

The result?

Well, it can no longer be considered "bass shy" - the mid-band is now under control, and the unit has a MUCH more uniform frequency response, and the perception that the speaker lacks bass is no longer valid.

Now we have a speaker that perfoms almost - if not exactly - like the "H", but with greater efficiency, too! At 4.87%, it is the most efficient 16" two-way of it's type ever built, as far we know - it's certainly more efficient than any Altec ever built. Not only that, but the "H" had the Mantaray horn - a vast improvement over the icky horn used in the C-G series, and the 704-8A has it, too!

The T/S's for the now-correct 704-8A are:

Xmax (inch) = 0.20
Re (ohms) = 6.80
Vd (cu. in.) = 19.20
Fs (Hz)= 30.90
Vas (cu. ft.) = 16.35
Ref. Eff (%) = 4.87
Qts = 0.261
Qms = 8.49
Qes = 0.270
Vid (cu. ft.) = 0.24

Incidentally, these improvements and T/S's are exclusive to the ICONIC Model 704-8A - the 604-8L off by ALPro is NOT the same speaker, nor does it share these characteristics (and it's more expensive). We think the 704 will rival, if not overtake, the 604-8G in popularity...

[spkrman57]

I called up Bill at Great Plains and he informed me that he no longer sells to the general public. :banghead:

But he did say that Iconic is who to contact those wonderful products. :applaud:

So Todd, it seems we will be chatting sometime in the future when I need some more drivers.:blah: :blah: :blah:

From those who know me, I can be long winded. But hope to establish the same cameraderie that I had with Bill Hanuschak at GP.

Looking forward to doing business with you in the near future Todd!!!:)

You might bring some of those Iconic toys up to Ohio for us to look at sometime!;)

Regards, Ron

[jimd]

Our number for the former 399 driver is 145-8 or 16A, depending upon impedance. This conforms to our inverted J L numbering system.

The 14= 1.4" exit throat, 5= 500 Hz minimum crossover-8 or 16 impedance, A is first vatiant. The lower power version with the old 288 diaphragm deviates somewhat from the numbering and and is the 142-8/16A. Here we picked the 2 as a counterpart to our lower power small format driver, the 102.

The 704 differs from former models with an optimized magnet structure with more linearity than any previous. In fact the 604K and L had the least lineartiy of any of all with their thinner top plates than the older alnico models. We took care to make sure our new higher temp voice coil assy does not change the fidelity of the driver. We still are using the regular length voice coil, however, with higher temp adhesives and former so the driver will be able to be used harder.

Thank you for all for your patience with our endevour, it has taken us a lot longer than we had hoped for to get to the stage we are now. JIM

[Earl K]

Hi Jim

I see the 145 driver is missing the housing extension of the 288/299 series .

- Did the 399 have this extra depth ? ( I guess I should ask Ron )

- Why the change to the shallower / flatter pancake style driver ?

<. Earl K

[Todd W. White]

The large format ICONIC compression drivers will soon have the large pot casting on them, like the ones you are used to.

The pot casting, Dr. John K. Hilliard told me, and Bill Hayes and Jerry Hubbard both confirm, lowers the mechanical resonance of the driver to a point lower than the lowest crossover frequency, thus minimizing the distortion that the driver generates caused by lower harmonics acting as fundamentals. The lack of this pot casting is one of the reasons the large-diaphragm drivers by "others" have a certain "ssssttthhhh" to them when people try to talk through them.

Nasty!

The newer Iconic's won't have this problem, even though in the current ones, it's not as bad, due to the smaller diaphragm (4" is just too large, folks).

[spkrman57]

I don't mean to make waves here but I know there was a debate about Altec 3" diaphrams versus JBL's 4" drivers and while the debate was "spirited", I am hard-pressed to really pick a driver that "does-it-all".

I think both companies have good products and I know you are rooting for the Iconics, but I look at the fact that they both are best when used in their best applications.

Ron


PS: Don't forget this is a Lansing family here. I like both for different purposes but I believe there is a JBL following here that will stay with their loyalty.

[Todd W. White]

No prejudice at all - I'm merely stating the truth: 4" diaphragms with 2" exit throats ALL exhibit distortion caused by the size of the diaphragm being just too large.

I am also stating that drivers without the large physical pot casting - regardless of the size of their diaphragms - also have distortion introduced into the audio path via the mechanical resonance of the device itself. This is why the mechanical resonance MUST be brought down to a point below the lowest usable crossover frequency, or you WILL have problems.

Lansing fans need to learn this, too! ;)

[Mr. Widget]

No prejudice at all - I'm merely stating the truth: 4" diaphragms with 2" exit throats ALL exhibit distortion caused by the size of the diaphragm being just too large.

With all due respect Todd, I believe John Meyer has more experience in this area and he says just the opposite. He uses 3" drivers over 1.75" drivers for lower distortion and 4" drivers over the 3" units to lower it further.

http://www.meyersound.com/support/forums/talkshop/drivers.htm

Widget

[Todd W. White]

Well, he can take that up Wente, Thuras, Blackburn, Don Davis, Dr. Paul Veneklasen, Dr. John K. Hilliard, Alexis Badmaeff, Bill Hayes, Mark Ureda, Cliff Henrickson, Scott Leslie, Ted Uzzle, and Jerry Hubbard (just to name a few), who have made statements supporting what I said. I don't think all of these distinguished men can be wrong...

Incidentally, you may be interested in a preprint of a paper that was presented at the AES by Jerry Hubbard entitled "Subharmonic and Nonharmonic Distortions Generated by High-Frequency Compression Drivers"

Here's where you can find it: http://www.aes.org/publications/preprints/preprints_search.cfm

Just go there, enter "Hubbard" in the author name box, and hit enter. Fascinating reading! ;)

[Mr. Widget]

Well, he can take that up Wente, Thuras, Blackburn, Don Davis, Dr. Paul Veneklasen, Dr. John K. Hilliard, Alexis Badmaeff, Bill Hayes, Mark Ureda, Cliff Henrickson, Scott Leslie, Ted Uzzle, and Jerry Hubbard (just to name a few), who have made statements supporting what I said. I don't think all of these distinguished men can be wrong...


For the most part those guys are dead or retired. JBL, TAD, and Meyer are all still in business and discuss in their technical papers how the larger diaphragmed drivers produce less distortion. I'll go with the living.

BTW: You can add Altec to the dead list... please take all of this as quite tongue in cheek. I doubt that we are talking about the same issue here as I doubt that there would be all that much disagreement between my group and yours. In simplest terms the large diaphragms yield lower distortion at higher SPLs since they physically move less to produce the same output. I have not yet read your link, but will.;) ;)

[Todd W. White]

You're not affiliated with Earl Geddes, are you? :blink:

[Mr. Widget]

No... but I hear he is still alive.:applaud:

Widget

[Mr. Widget]

BTW: I tried to read Hubbard's pre-print... I am no longer an AES member and don't want to spend the $20. What was the gist?

Widget

[Todd W. White]

Exactly what I've said earlier, and much more...

E-mail me your snail mail address and I'll send you a photocopy.

[spkrman57]

Why is the world still using those 4" drivers?????

I think this "theory" should be put to the test with modern testing equipment.

I don't have the necessary equipment but maybe someone on this forum would be willing to undertake this testing and end the myth's once and for all.

I would not be so stubborn on this topic, but your stubborness seems to drive my desire to put you to the test!

And I still don't understand why you and JD are pushing the issue on the Lansing forum all the while your comments seem to imply the JBL drivers are inferior.

I happen to use Altec compression drivers quite extensively, I am not a engineer or scientist. But I refuse to cut down one OR the other designs.

They are both great designs, and I like them both.

I just have a problem with your biased opinion.

I apologize in advance if you take this wrong, I am a hobbyist and like to look at the big picture with a open mind!

Regards, Ron

[Todd W. White]

When did I say "JBL"????

[spkrman57]

And JBL is most well known as a major manufacturer of 4" diaphram drivers.

Or an I the only one that felt that way???????????

Ron

[Zilch]

http://audioheritage.org/vbulletin/showthread.php?t=4410

[Mr. Widget]

Thanks Zilch,

I was too lazy to dig it up. That is the technical paper from JBL I was thinking of. I have read similar things from both Meyer and TAD as I mentioned. Obviously they are all wrong though since "all of these distinguished men can be wrong...":D

I imagine we are talking about different types of distortion or something along those lines, since I doubt the distinguished crowd is wrong and I doubt JBL et. al. is wrong either.

Widget

BTW: Zilch did you read the bit about 1" exit vs. 2" exit drivers as used in two-ways?;)

[Zilch]

BTW: Zilch did you read the bit about 1" exit vs. 2" exit drivers as used in two-ways?;)Where? Can't find it, 'cause I read selectively.... :p

[Am I good at 1.5"?}

[Mr. Widget]

Where? Can't find it, 'cause I read selectively.... :p

[Am I good at 1.5"?}

Here you go. I hadn't read that document for quite some time. I guess it doesn't actually say "Hey Zilch, in a two-way design you should use..." Essentially it says a well made 1" exit or 2" exit will exhibit similar HF extension. It is an issue of mass break up which is a power to weight ratio issue.

At the time of this document JBL did not make 1.5" exit 3" drivers... obviously they do now. Todd's comments not withstanding the 1.5" exit 3" drivers should have lower distortion (2nd and 3rd harmonic) than the 1" exit 1.75" drivers, but not be quite as low as the 2" exit 4" drivers. Furthermore 1.5" exit 4" drivers like the JBL 2451 or the TAD 4003 have the lowest distortion.

I have sent Todd a PM with my info and do hope to read Mr. Hubbard's AES Pre-print... it should prove interesting.

I guess we have wandered off-topic a bit, as this was essentially an announcement thread... still interesting stuff.

Todd, if you would like to lend me one of your drivers I could measure it for 2nd through 5th order harmonic distortion and compare it to the JBL 435Be 3" driver and TAD 4003 1.5" exit 4" diaphragm drivers all on the same 1.5" horn.

Widget

[spkrman57]

Is the JBL 1.5" driver throats and Altec 1.4" throats the same? Or is the .1" difference a matter of concern when mating up to the horns?

I have a pair of 311-60's(wish I had a pair of 311-90's instead but..) and using them with 288C and wondering since 1.4" Altec is the only one I have seen, are they compatible with other folks 1.5" throat horns???

I guess Altec wanted to be unique as everyone else uses 1.5".

Ron

[Ian Mackenzie]

For the most part those guys are dead or retired. JBL, TAD, and Meyer are all still in business and discuss in their technical papers how the larger diaphragmed drivers produce less distortion. I'll go with the living.

BTW: You can add Altec to the dead list... please take all of this as quite tongue in cheek. I doubt that we are talking about the same issue here as I doubt that there would be all that much disagreement between my group and yours. In simplest terms the large diaphragms yield lower distortion at higher SPLs since they physically move less to produce the same output. I have not yet read your link, but will.;) ;)

Might want to run this by Steve Schell.

I once asked Thomas Dunker what to use...a two or four inch driver...his response was the larger driver is better for mid band and the smaller driver better for upper mid and HF. Perhaps then 3 inch is a good compromise.

Thomas Dunker is still alive and very highly regarded in the field of horns, particuarly his work with VOT and exotic Japanese horns and drivers.

Ian

[Mr. Widget]

I once asked Thomas Dunker what to use...a two or four inch driver...his response was the larger driver is better for mid band and the smaller driver better for upper mid and HF. Perhaps then 3 inch is a good compromise.

That was the commonly held belief and the reason I posted this excerpt from the JBL Tech sheet. In comparing say a LE85/2420 with a 375/2440 it does hold true, but with the newer designs it no longer seems to.

Widget

[Mr. Widget]

Is the JBL 1.5" driver throats and Altec 1.4" throats the same? Or is the .1" difference a matter of concern when mating up to the horns?

I have a pair of 311-60's(wish I had a pair of 311-90's instead but..) and using them with 288C and wondering since 1.4" Altec is the only one I have seen, are they compatible with other folks 1.5" throat horns???

I guess Altec wanted to be unique as everyone else uses 1.5".

Ron

You got me... I have used drivers and horns that were spec'd at 1.4" and those that were spec'd at 1.5" and have to admit I've never actually measured either and I haven't put the drivers of one brand on the other brand's horns. I have been more involved with 2" drivers and some of them actually are 2", but most are actually just under... the 2440 for example is actually 1 15/16".

As far as Altec using 1.4" to be different... I think they picked 1.4" before the others picked 1.5".

Widget

[spkrman57]

I guess I have not seen any 1.5" horns yet. My 1.4" horns are the 311-60's and don't have anything else to compare to.

Ron

[Don McRitchie]

As a bit of trivia, the 1.4" throat diameter of Altec's large format compression drivers is a legacy of the Lansing Manufacturing product line that Altec bought in 1941. The Altec 288 was basically an improved, permanent magnet version of the LMCo 284 developed for the Shearer Horn in 1935. It used the same diaphragm and throat geometry. The exit throat diameter on the 284 was originally 1.5" in diameter. However, this dimension was at the end of a screw on horn connector that extended out past the body of the 284. Later, Lansing switched to a flush flange connection for their horns that was fastened by three bolts that passed through the flange. This resulted in cutting back the horn throat for a length equal to the height of the former threaded mount. The diameter of the throat at the point where it is flush with the compression driver body was 1.4" and thus this became the standard. You can see this in the picture below taken by Steve Schell of one of his 284's next to a 288D.

[spkrman57]

That answers a lot of questions I had on the throat size.

Ron

[Todd W. White]

There were REASONS Blackburn designed them that way.... hint-hint

[Mr. Widget]

There were REASONS Blackburn designed them that way.... hint-hint

Maybe because back then it was very difficult to manufacture a driver with the required tolerances necessary to produce a viable 4" diaphragm, 2" throat driver?

Widget

[Don McRitchie]

There already was a viable 4" diaphragm 2" exit driver from that era, the WE 594. It was developed in 1933. The 375 was pretty much a copy of the 594, replacing the field coil with a permanent magnet. Hilliard stated in an article from the 70's that they investigated a 4" driver during the development of the Shearer Horn, but found that it did not have good "power response". I have no idea what he was referring to. Hilliard developed his own 4" diaphragm, 2" exit driver in the late 60's as part of the ill fated A10. The only reason it was not put into production was that he was overuled by management. Altec did not want a driver that obsoleted their current horn product line, not to mention validating the technology of their main competitor - JBL.

[Mr. Widget]

I was speculating that perhaps Altec thought the 3" driver was the better compromise since it didn't require quite as large of a magnet to achieve the same gauss level in the gap and also as the diameter of the VC and diaphragm increases it gets significantly more difficult to maintain tolerances. (difficult but not impossible)

Widget

[Steve Schell]

Great discussion, guys. Todd's comments about the larger magnet on the 604 accentuating the midband response and making the bass seem shy make sense to me. When the bl is increased, it pushes the mass break point higher, raising the frequency at which the efficiency begins to roll off due to mass effects. Most high bl drivers exhibit a rising response anyway, unless they are loaded by a slow flare horn that affords adequate loading and directivity control of the lower frequencies. This is why small high bl drivers like Lowthers are often fitted to large rear loaded horns. My 20' path, 15Hz. subwoofer is fitted with an Altec 515-16G driver, and exhibits a very strong midrange response; it is almost as loud at 500Hz. as it is in the passband of 20 to 80Hz. unless it is steeply low passed. This was surprising, as the design has three almost 180 degree folds.

The three stud mounting for the large format driver began with the Lansing 287. This occurred before the sale of LMCo. to All Technical, as I have seen 287s with the LMCo. metal tag. The three stud mount began with the small format 801 driver in 1937, and was likely adapted to the large format driver in 1940 or so. This method of driver attachment greatly simplified manufacturing of both driver and horn throat, and simplified alignment of driver to horn.

The 2 1/2", 16TPI mounting standard of the early Lansing and RCA drivers was likely derived from Wente's original 4" diaphragm driver as built experimentally for the Fletcher System. Pictures of the Fletcher h.f. driver appear to show a 3" threaded mount with a 2" exit hole. In general, the earliest Lansing drivers as built for the Shearer Horn System bear a very strong visual resemblance to the Fletcher driver, though scaled down in size, and utilizing an assembled pipe pot structure rather then the cast pot structure of the Wente driver.

Why did the Shearer team reduce the format size of Wente's driver? This is a question for the ages. The whereabouts of Dr. Blackburn's writings is unknown, and they are likely lost. The majority of Jim Lansing's papers were lost in a garage fire. What we do have is a reference to the issue in John Hilliard's article "Sound Reproduction", published in Audio magazine in March 1977. In the article he states that the 4" Wente driver with annular compliance "...proved to have poor power performance."

We also have Dr. Hilliard's Technical Bulletin titled "A Study of Theatre Loud Speakers and the Resultant Development of the Shearer Two Way Horn System" which was published by the Academy Research Council on March 3, 1936. Here's a quote:

"One of the features of the reference system is the use of a single diaphragm to reduce phase distortion. Inasmuch as theatres require parallel operation as protection in the case of failure of one unit, experiments were made with a Y throat and two units. As a result of these experiments, it is now recognized by all concerned that any increase in phase distortion which may be introduced by the Y throat is negligible."

This bulletin was reprinted in modified form in the Academy's 1938 book Motion Picture Sound Engineering, in the Chapter titled Loudspeakers and Microphones. Material was added to the text, including this:

"To obtain high efficiency energy transfer between the diaphragm and air column in an exponential horn loud-speaker, the acoustic impedance of the air must be matched with the mechanical impedance of the diaphragm. Such an impedance match is usually secured by the use of an acoustic transformer which provides a properly constricted cross-sectional area of the sound channel between the diaphragm and the throat of the horn."

So what do we make of all this? The Shearer team did experiment with different high frequency driver format sizes. I bought an early Lansing driver a while back that was probably a part of this process. Model 199E, serial #10, it uses a 2" diaphragm and 1" exit. My theory of the moment is that the Shearer team found that the twelve square inches of Wente's diaphragm was correct for impedance matching. They likely also determined that they could achieve higher output with lower distortion by realizing that area with two diaphragms of six square inches each. This was also a more practical arrangement for their commercial system, in that the show could continue in the event of failure of one of the high frequency diaphragms.

Todd, you have Dr. Hilliard's papers. Are there any mentions of this development process in his research notes from the period that could shed more light on the decisions made by the Shearer team?

[spkrman57]

I hope everyone keeps coming up with info and we may all get a good history lesson at the same time.

Just for the hell of it, I have to say that regardless of the diaphram and exit(throat) size, design engineering has more to do with the overall end product success than just the size. IMHO

Ron