This information from Paul Plier fron the Grand-Duchy of Luxembourg:
McIntyre System Clarinet was probably manufactured by Thibouville Frères.
Information of fingering from Ken Shaw at the woodwind.org clarinet forum:
On the McIntyre clarinet, you'll see four pads in a row above the open hole for your left index finger. The bottom one opens when you lift your thumb for open G.
The next pad up, for Ab, opens when you put down your left ring finger.
The next one, for A, opens when you put down your left middle finger. If your left ring finger is not already down, this also opens the Ab pad.
The top pad, for Bb, opens when you put down both your left middle and index fingers. (It can't be operated by just your left index finger, since then you would lose the usual fingering for F#.
There's a good thread at http://www.sneezy.org/clarinet/BBoard/read.html?f=1&i=37401&t=37389 .
I met Mr. McIntyre at a show many years ago. He was a great enthusiast and played pretty well on his instrument. However, the change in fingering was big enough that you really had to stop playing for a while until you learned it thoroughly, and so it never caught on. Also, the instruments themselves were not top-line quality.
Information from the U of A clarinet collection.
From a private conversation with a person who had worked with the McIntyre brothers in designing and promoting this system when it first introduced in 1950s. (The McIntyre System was granted patent in 1959)
"Thomas and Robert Mclntyre had a music store in Naugatuck, CT and were repairmen and engineers. They worked many years on a new configuration that would eliminate the problem of "Cross the Break" Thomas McIntyre had made many prototypes to test. After they had come up with their best model, they applied for, and eventually were granted a patent. After their new invention was introduced, it was well received and even the famous clarinetist Bonade endorsed it. They had the clarinet bodies and keys made by a company in France (Thibouville Freres, Ivry-la-Bataille) and they assembled them in Connecticut.
It is a hard sell because it has to use different fingerings in throat-note. But the biggest drawback to their clarinet was the weight and complexity of the new mechanism. They had solutions for it, but by this time, they were out of money and couldn't make the improvements on their own. (They funded all of this on a shoestring and through banks and mortgages) They went to a major clarinet manufacturing company (for legal reason the name will be disclosed) to try to sell their idea to them and work with their engineers on the remaining problems. It was well received, but the company stipulated that the only way they would do it was if the Mclntyre brothers sold their patent to them. They refused the offer and Tom mentioned that the president of the company was so angry that he told him, he would see to it personally that the clarinet would fail.
They continued selling and marketing the clarinet on a small scale, but indeed the 'word' was spread that this was a bum invention".
Also I copied these files from the UArk collection:
Serial #5213 “L1” batch mark.
Barrel: no original barrel or bell, using a 65.3mm plastic barrel for this test
Bore LH joint top: 14.6nn
Bore LH joint at bottom: 14.6mm
Intonation results taken when playing loud and not lipping. See how to interpret these results on the Model Comparison Page.
For this test, I pulled .9.. at the barrel and .3mm at the center tenon.
This clarinet currently resides in the collection of David Watson of California.
Intonation summary: The two throat tones marked are flat because of an as-yet unsolved problem in regulating the McIntyre special keys. Sorry! I am sure these two notes will play in tune with proper regulation. This is very solid intermediate intonation. This clarinet can be played in tune.
Key work quality: Very nice. I have found it very hard to get the mechanism to work properly. The adjustments for spring tension are tricky. In some cases one spring raises one key and must overpower another spring to lower another key.
This clarinet is most appropriate for: People who hate the normal fingerings for the throat tones and want to have something that does not require the left hand to move out of position. If you learn this clarinet, you will not want to switch back and forth to the regular Boehm system. I don't think you will find a McIntyre A clarinet. For this reason, people who play in orchestral settings will not want to consider a McIntyre system clarinet.
Condition issues noted: None.