Frankensax’s Offspring Gets Its Patent

For the March/April 2009 edition of the Saxophone Journal, University of Washington’s saxophone professor Dr. Michael Brockman, wrote an article titled: “The Frankensax: An Experimental 12 Octave Vent Saxophone“. The article discusses the current 2 octave vent system most saxophones have, and why this is problematic. The article then goes on to describe how Brockman went about designing an intriguing, but highly impractical, multi-vented saxophone that utilized 10 manual vents strategically placed over the horn, in addition to the 2 conventional automatic vents.

The result of these strategically placed, manually-operated octave vents? According to Michael Brockman, the experimental sax gives the player “a choice of twelve octave vents to open at will for any note…fingered on the saxophone”1, thereby increasing the chances of creating a “perfect octave”.

Frankensax’s offsping: the Broctave Key

Fast forward 3 years, and an offspring of this Frankensax received its patent last November. Rather than having extra octave vents drilled into the body, Brockman developed a method by which to preserve the original saxophone by adding only 1 extra vent into an existing key. This is how he describes this new key, now called a Broctave Key, on his website:

Because I did not want to drill a new octave vent into my 1952 Paris Selmer Super Balanced, I wanted a device that could be inserted into an existing key of the instrument–one that could be changed or replaced in case I did not want the addition of a new octave vent to be permanent.

Thus, The Broctave Key, U.S. Patent No. WO-2010-068909A2.

Here’s how it works: A small vent is drilled anywhere along the body of a saxophone where an octave key is desired. To avoid permanently altering the instrument’s main body the small vent can be drilled through any existing key on the saxophone. The Broctave Key, a piston-operated mechanism, sits on top of the newly-drilled vent and gives the saxophonist the option of using it for some of the notes that are most likely to be out of tune, such as middle D. Using a piston instead of a lever solves space problems and simplifies installation… If the Broctave Key is mounted onto an existing key, the player can switch back and forth between the standard key and the one with the new Broctave Key attached, as performance situations require. Though the piston could be applied to any key, Brockman considers the high D key to be the most likely candidate because of its heavy use in saxophone repertoire and the challenge of playing the note D in tune.

I did some checking for the various patent numbers that the Broctave Key was assigned, and finally came up with this one, which included the drawings. Here is what the Broctave Key looks like…

Broctave Key, patent drawing, Frakensax offspring by Michael Brockman, third octave vent key for palm D key on the saxophone

Source: Google Patents

Brockman got help with his patent application from the UW Center for Commercialization (C4C). The C4C is still involved with Brockman as they move towards the final version of the Broctave Key.

According to Deborah Alterman, an engineering technology manager at C4C:

Some of the things that make this valve novel and valuable are that it has been designed to have an optimal air flow rate… It’s easy to use while playing the instrument, and has the flexibility to be implemented on either a replaceable key or an existing saxophone.

Source: Music professor retools and retunes the sax. The Daily of the University of Washington, May 7, 2013

According to an April 11, 2013 article from, in his quest to solve the saxophone’s intonation problems, Michael Brockman’s turned to the work of physicist Arthur H. Benade.

Benade’s theories predict that if you create new octave vents in just the right places on a saxophone, you can fix the instrument’s tuning problem.

Source: Seattle Inventor Finds Key to Solving Saxophone Discord., April 11, 2013

Sounds rather simple in theory doesn’t it? So simple in fact, it’s a wonder that no else has come up with it before now.

I don’t know about you, but I’m rather more intrigued by Frankensax than by the Broctave Key. I think trying to play a 12 octave key sax would be interesting, and yes, quite challenging.

As far as the Broctave Key is concerned, it will be interesting to see if this invention by Dr. Michael Brockman will have legs.

Further Reading

Here are some page links that you might find helpful for further research. There are likely quite a few more, but this will at least get you started.


1 Source: “The Frankensax: An Experimental 12 Octave Vent Saxophone“, by Dr. Michael Brockman. Saxophone Journal, March/April 2009, p. 3.

…this is just my blog. My “real” website is If you’re looking for sax info, you should check it out too.There’s lots there!

© 2013, Helen. All rights reserved.


Helen Kahlke is a professional horn player and sax teacher who lives in Abbotsford, British Columbia. She plays soprano, alto, C melody, tenor, baritone, and bass saxophones.


  1. Pingback: Favorite blog posts, May 2013 | Bret Pimentel, woodwinds

  2. The idea to make a vent in an existing key is not completely new.
    Take a look at the low D key of this Adler baritone:

    It is at the moment with the famous Bluespeter1.
    I have seen a similar picture of a Buescher and this type of construction has been used for the high Csharp correction of soprano saxophones. Somewhere I have similar parts of a Pierret alto. When I find them I will send you a picture.

    The construction of the Broctave key is still different from this old example, so the patent still stands.

    • Interesting that you point out the old Oscar Adler. I have actually seen something similar as well, but I’m not sure on which vintage saxophones. I’ll have to pour through my gallery and see if I can find them.

      Oh, I did find one of them. Here is an Oscar Adler Triumph model alto. This was of the duplicate left/right hand keys (Eb), which also allowed you to trill easily on some of the lower notes I believe.

  3. Hi Helen,

    The acoustics of this is quite sound (sorry). Coming up with a mechanism that activates the correct vent reliably without costing a great deal to fabricate and maintain has been the reason two vents have been considered “good enough”. IIRC, Yamaha has been one of the few modern sax makers to put some serious research effort into this. It still remains to be seen how this will integrate with current saxophone key-work to provide an easy-to-use third vent.

    The oboe has a similar bore, faces similar venting problems, and has long had a system of three vents. This involves using the index finger of the left hand, though, and that would conflict with established key-work on the saxophone.


    • Hi Paul,

      There are also some saxophones with a three vent system, made by Couesnon and Conn.

      • I believe Yamaha uses three vents on some baritones to assist in venting a weak second-octave D and Eb. I’ve also seen a bass with three vents, though I don’t know if that was an aftermarket modification.

        • Interesting list. Of course I’d be remiss if I didn’t mention Hammerschmidt.

          I’d be curious what brand of bass might have a 3rd octave vent. I can’t think of any off the top of my head. You’re right Mal, it might have been done aftermarket. Nonetheless, the horn you saw, was it in person? Or was it on the web somewhere? Do you remember?

          Edit: It took some digging, but I found a photo in Bassic Sax Pix of the Conn in question with the 3rd octave vent. I never remember which model it was, but here we go, it was the the 28M Connstellation (alto). This is the model that Conn never made a tenor version of.

          I’m going to poke around in my gallery and see if I can find any Couesnon horns with a 3rd vent. It will be a long shot, since that brand is not well represented on my site.

          • The bass was one I saw in person, and actually got to handle (though not play). I think the third vent WAS aftermarket, because the owner complained about life without it, having to crack palm D to get the second octave D to speak reasonably. Then again maybe she meant a prior horn.

          • Hi Helen,

            You have to look for a Coesnon monopole conservatoires.

            Rare and beautifull instruments.
            Some of them have the three vent system.
            There is also a rumour they made Bass saxophones.

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