Mouthpiece Maladies
By Clay Konnor

Let me start by addressing some of the comments in the EWI manual. This is the shorter manual that came with the instrument. There was a lot of language in the manual to hold the mouthpiece with your lips only and not your teeth. There are, in fact, some warnings that you will damage the mouthpiece if you apply too much pressure. Akai later issued a correction to the manual instructing players to hold the instrument in their mouths between the top teeth and bottom lip, just as you would a sax. The original advise of not applying too much pressure, however, is sound advice. As I will explore in this article, some problems can be caused by excessive pressure to the mouthpiece. Add to this that Akai provided no mouthpiece cover and you have a real source of problems. I have seen plenty of EWIs that were simply dropped on their mouthpiece and started acting squirrly. I'll explain the reasons for this in this article and hopefully offer some home-spun solutions to the most common mouthpiece problems I've seen.

One of the largest contributors to mouthpiece woes is the wide variation in playing styles, vibrato styles and the adaptation of the player's sax skills and habits to the EWI. While a technician at IMC might feel the bite sensor is working great, I could think that it feels totally dead. Akai tried to compensate for this by placing the vibrate knob within easy tweak range of the player and by providing for the programmability of the bite sensor itself.  Further, no two EWI bite sensors that I've tried behave exactly the same.

LITTLE OR NO BITE SENSOR RESPONSE

This is probably the most common complaint of EWI players and is the most logical starting place for trouble-shooting any bite sensor problem. If you've been wondering why you can't reproduce that Brecker or Everette Harp sound, it could very well be because your bite sensor is not working properly. One very problematic item here is that there doesn't seem to be a standard at which the bite sensor works. If you haven't played any EWI but your own, particularly if you bought yours used, I encourage you to play some other EWIs. A friend of mine had his EWI for a year before trying mine only to find out that his bite sensor barely functioned compared to mine. Generally speaking you should be able to create a nice wide, square vibrato with the vibrate knob at 12 o'clock. You should also be able to make the sound go nuts if you crank the vibrate knob.

If your EWI is not producing enough vibrato try adjusting the VIB VCO parameter first before we crack the thing open. I currently run the VIB VCO on all of my internal EWI patches at 35 and at 45 for external sources. (More on the relationship of external patch and internal patch vibrato later). Take your favorite internal patch and crank the VIB VCO to 35 or higher and see what happens. There is a direct relationship between the vibrate knob and the VCO and other bite parameters so play with it for awhile. If you still don't get satisfactory vibrato with the vibrate knob cranked and the VIB VCO turned up, chances are you have a sensor problem.

With the EWI disconnected from the EWV and using a #2 phillips screwdriver remove the access panel on the back side of the top part of the EWI. Remove the rubber collar at the base of the mouthpiece by pulling it straight off. Remove the access panel. This will expose the bite sensor and breath sensor connections. In case you didn't know, the mouthpiece is divided into two tube like sections. One side contains the bite sensor and the other side (the side with the hole) contains the lead tube that carries breath to the breath sensor. The bite sensor is made up of two metal "ribbons" that are bolted together at one end by two tiny plastic nuts and bolts. The metal ribbons are joined at the one end and should gradually slope away from each other. If the metal ribbons are flat against each other or bent, gently adjust them to look approximately like the those shown in diagram 1. A greater slope or distance between the tips doesn't necessarily yield more vibrato. It is the relationship of the metal ribbons that matter. The metal ribbons sandwich a clear plastic ribbon, represented by the orange line in the diagram. In some EWIs this plastic ribbon runs the entire length of the metal ones. In others the plastic ribbon only extends to above the screws.

The bottom of the bite sensor will be extending below the mouthpiece. With a finger on it, pull the mouthpiece from its mounting post. This will probably disconnect the breath tube from the breath sensor, which is fine. Set the mouthpiece aside for the moment. Now plug your EWI into the EWV. With your hands in the playing position, turn the outer breath knob until you have a steady strident tone. Now grab the bite sensor with your right hand and gently squeeze it, compressing it and releasing it. You should have a monstrous amount of vibrato. If you do your bite sensor only needs adjustment, if you're getting nothing something more is amiss.

If you get no vibrato this way, then check the connections of the little pink and white wires. These should be soldered to the base of each metal ribbon and taped so as to avoid contact with each other. It is very common for these leads to become loose or unsoldered, so check them carefully.

If you got vibrato from the hand test try experimenting with different depth insertions of the ribbons in the mouthpiece. I have discovered that the depth of the bite sensor in the mouthpiece makes a great deal of difference. Sometimes the vibrato sensor will work fine in your hand and then not in the mouthpiece because of placement. I've even had one that worked great with the access panel off and then didn't work with it on. These types of problems generally have to do with the placement of the bite sensor in the mouthpiece. A glob of hot glue on the bottom of the sensor will keep it from moving around.

Here's a good one, the bite sensor works well with the back access panel off, but when you put it back on it stops working or works less. The best I can tell this is caused by pressure on the rubber collar that sticks out of the mouthpiece. Shaving this collar off with a razor or utility knife usually remedies the problem. Be sure, however to caulk around the mouthpiece where it meets the body of the EWI if you do this, otherwise, condensation will stream into the EWI and you'll have breath creep, poor grounding and a host of other problems on your hands. I use a hot glue gun with caulk sticks, but zip seal also works well.

I have also noticed that later EWIs have a much harder mouthpiece that the earlier ones and require much more bite. The biggest problem with these is that they don't "snap back" fast enough causing a slow response. This is particularly important to producing pitch bend or wow type effects from the mouthpiece. This can be remedied by simply removing the rubber mouthpiece and chewing on the middle part breaking it down slightly. If this doesn't do the trick you can slice the divider between the two sides of the mouthpiece a little at a time using a utility knife. Don't go too far though!

If you still don't have satisfactory vibrato happening try trimming back the plastic divider between the metal ribbons. Do this a little at a time and test it each time to hear the difference. As I mentioned some of the older EWIs already have a very short plastic ribbon, so this won't be an option here. You can't totally remove the plastic ribbon as it will cause constant contact between the metal ribbons and thus a spurrliness problem. Which leads us to the next most common complaint:

THE SQUIRRLY MOUTHPIECE

Another commonly seen problem is squirrliness, that is to say unpredictable or radically exaggerated vibrato. The most obvious remedy for this problem is to turn down the Vibrate know and check the settings of the VIB parameters in the EWV. One common cause of spuirrliness is the slipping of the metal bite sensor ribbons against each other. This is caused by one or both of the little plastic bolts coming loose or breaking. Check the plastic bolts and gently tighten them with a #1 screwdriver and a needle nose pliers. Many times doing this will break the screws. If this happens or you discover that your problem is being caused by a broken screw try the following procedure.

Remove the tape at the end of the ribbons to expose the connections of the pink and white wires. Using a soldering gun disconnect these wires and clean the area with a solder remover. Remove and discard the plastic bolts. Cut a piece of shrink wrap tubing, available at any Radio Shack about a quarter inch long. Slide it over the bottom end of the ribbon and heat it with a candle to shrink it into place. Don't use a butane torch as it may damage the ribbons and will melt the plastic ribbon.

Another method for curing squirrly mouthpieces or non functioning mouthpieces is to move the contact point of the two ribbons up. To do this use a piece of electrical tape and try different positions on the metal ribbons. Start towards the bottom and move your way up. By establishing a "higher" contact point you will raise the zero point, or starting point for the vibrato. Once you have found a position that works cut a small piece of shrink wrap tubing and shrink it to the new contact point.

One other method suggested by a player by the name of Craig Hara is to use a piece of a cotton ball between the ribbons to create a little more "springiness". I've had good success using this method on a couple of EWIs.

DIFFERENCE BETWEEN EXTERNAL VIBRATO AND INTERNAL VIBRATO

This is a problem that I have heard complaints about very often. Let me start by saying that because of the way the EWI and EWV interact it is not, in my opinion, fully possible to get as good of a vibrato effect with external synths as it is on an internal patch. Having said that, however, let me assure you that a very realistic and effective vibrato can be achieved from your external gear. It is necessary for you to first understand how the EWI's vibrato is actually working on external gear. Keep in mind that the EWI and EWV is a CV (control voltage) system. That is to say the EWI sends voltage information to the EWV2000 or EWI module.  These changes in voltage produce a stream of smooth information that is interpreted by the EWV. Your external gear is not operating with CV or even if it is as in the case of an Oberheim Expander, your are not controlling it using CV. A few ancient synths had a CV out port on them. This was used effectively by Lyricon players such as Tom Scott and Richard Elliott.

When the CV data from the EWI is sent by the EWV to your external gear it is sent in MIDI format, which has a maximum of 127 "steps". The data is changed by the EWV to MIDI pitch bend information. That's right, pitch bend. This digitized message is far less "smooth" than the CV. This accounts in part for the difference between vibrato in external and internal patches. Because your external gear is receiving pitch bend data the programming parameters of your external gear for pitch bend will affect how the pitch bend works. Unfortunately most synths have but one parameter for pitch bent that controls the amount of pitch bend in semi-tones of the scale. The pitch bend parameter on the EWV is set up this way as well. Obviously, this setting should be set consistently with the external gear. This yields a total of 12 positions.

For most sounds the best setting for most gear for pitch bend is around three (3) on the scale of 1 - 12. Unless you are looking for a strange detuned effect set the pitch bend on all of your gear to the same number. Some equipment allows for the pitch bend amount to be assigned to the patch, others have it as some sort of global programming that affects every patch. Keep in mind that if you set up some sort of Multi or Performance patch that the pitch bends of each of the individual voices should be consistent.

If you're not using the External In port on the EWV, start using it. It can really help smooth out sounds. Check out Sam Zambito's article on using the MB-76 to maximize the EXT IN port. Even if you're not lucky enough to have an MB-76, the article contains many hints on EXT IN programming. If you're unfamiliar with the effect of the EXT IN port examine diagram 2 below. This graphically describes the path of the signal after it is returned to the EWV by way of the EXT IN port. Some players turn the vibrato on their external gear off and simply rely on the vibrato of the post EXT IN stream. Give this a try.

Hopefully this has enlightened you somewhat in regards to the bite sensor and its various problems. I should mention that you can get new bite sensor parts from IMC in Texas. This doesn't always remedy the problem though. Keep in mind that each problem is a little bit unique and varies by your playing style. I've found that adjusting and working on my own EWI has proved more successful that sending it to IMC for repair. As you can see from the suggestions herein, most problems are pretty easily cured.