"Breath Creep"

Question: My EWI plays fine when I start it up but as I play I keep having to turn the breath sensitivity down. If I don't the EWI will emit sound without me blowing into it.

Answer: The problem you describe here is something I have nicknamed "breath creep". This phenomenon can be caused by a couple of different sources. One of the most common is heat. As the unit heats up, particularly if it is left under stage lighting, the metal contacts in the "breath block" and the metal ribbons used as the bite sensor expand. You can view the breath block by simply removing the access panel below the mouthpiece. Another very common source of this problem is moisture. When moisture enters the chamber holding the breath block it actually acts as a conductor tricking the instrument into thinking it is receiving breath when it's not. This is usually characterized by the instrument ultimately producing sound even when the breath sensitivity is all the way off.

The remedy for the heat up situation is simply to avoid hot lights and other heat sources. You may need to turn the sensitivity down after playing for awhile, but the other remedies discussed here are also relevant to this problem. One area to check is the bite sensor ribbons themselves. (See the article "Mouthpiece Maladies" for some background on the bite sensor). One function of the bite sensor is that at extreme compression it actually will produce a sound out of the EWI. Don't believe me? Take the bite sensor ribbons in your hand and squeeze them all the way together. The EWI will produce a short burst of sound. My theory on this is this is done so that when the instrument is receiving maximum breath input the bite sensor will still perform correctly.

The next area to check is the breath block. In the earlier EWI's the breath block that covers the area where the breath tube leads has a circuit board on it. The circuit board has a number of exposed contact lines. At least one of these (the bottom left one) can conduct with the bottom left screw that holds the board down. This can usually be remedied by blobbing a little hot glue on the screw head, or in extreme cases removing the screw and blobbing. If the breath block shows a lot of corrosion, it is a sign that moisture is building up in this area. Be sure you have the rubber "O" ring in place at the bottom of the mouthpiece. You can also try to put a sweat-band or pony-tail tie at the base of the mouthpiece. (The sweatband you have seen Brecker use is further down and is used to keep spit from seeping down to the octave rollers...ick). You can also caulk the area where the mouthpiece meets the instument and then push the "O" ring into the caulk. If the problem persists, you can cover the entire breath block with hot glue. I have found that the hot caulk sticks work really well for this purpose. Lastly, be sure to check the connection of the breath tube to the breath block. If this is leaky, caulk it!