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E-Cymbal --- 3 zone ride with choke

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  • E-Cymbal --- 3 zone ride with choke

    Here's some pictures of the ride cymbal I completed last week. It's made from an 18" Pintech plastic practice cymbal with a cut up Vic Firth drum mute. I'm using a total of 4 piezos on it, one for the edge and 3 wired in parallel for the bow/bell to give me a fairly large playing surface with good output all across it. I'm using an electronic touch switch that I described in my crash & splash post for choking and I'm using a modified Keith Raper circuit for the edge switch. The module uses velocity information to discriminate between bow and bell sounds. I'm using small circles of the drum mute mounted directly over 2 of the piezos close to the bell. Hitting these with the shoulder of the stick generates the bell sound. Electronics are mounted in a 1" x 2" x 4" plastic Radio Shack project box.
    Attached Files

  • #2
    Hey John,

    Very cool stuff. I am curious, how well the edge triggers. The reason I ask is that I am currently using the "stock" Raper circuit on my edge piezo and notice that when I really wack the edge, it tends to choke the cymbal sound. I haven't tried your mods yet but perhaps they alleviate the problem?

    Thanks,
    lidrummer

    Comment


    • #3
      Hey lidrummer. I've seen the problem with the "stock" Keith Raper circuit where when you really whack it, it chokes the sound. I've done an extensive analysis of the circuit using circuit simulation software and field testing as I explained in another thread (I'm an EE and musician - dangerous combination ). Bottom line here is that your circuit is too sensitive. What happens is that when you hit the edge piezo it produces a decaying sine wave output waveform (frequency depends on the piezo size --- 27 mm = about 4.5 kHz, 35 mm = about 2.6 kHz for the DigiKey piezos that I and many others here seem to be using). The circuit looks for peaks in the waveform above a certain threshold (set by the pot or by the series/shunt resistor combination). When a peak above the threshold occurs the transistor turns on, effectively switching the "ring" circuit to ground. Now, exactly when you switch the "ring" circuit to ground determines whether you get the edge or choke sound. To get the edge sound you need to switch simultaneously (or nearly so) with the output from the main (bow) piezo. If you delay switching for a certain amount of time (hard to say exactly how much as it is a function of the time it takes the module to scan all its ports, but my best guess based on analysis and testing is several milliseconds), then what happens is that the module interprets this as the choke signal. So what happens when you hit the edge really hard is that you get a really big waveform out of the piezo. This causes the circuit to switch from off to on and back to off a number of times. The first time it switches on is simulataneous with the signal from the main piezo. This produces the edge sound. If the circuit output is still switching (as would be the case from your really hard hit) the next time the module scans that port, it interprets that as the choke signal. Bottom line here is that you get a very short edge sound and a nearly instantaneous choke. What you need to do is reduce the sensitivity of your circuit by increasing the series resistor from the piezo to the base of the transistor (usually shown as 100K), decrease the resistor from the base of the transistor to ground (usually shown as 1M), or a combination of the two. Have a look at the "Fine Tuning the Keith Raper Circuit" thread. There are two modified versions of Keith's circuit shown there that are much easier to adjust than the original and do not suffer from the problem you describe. Good luck!

      Comment


      • #4
        Hey John,

        Fantastic write-up! I'm not an EE but an ME and the way you have descibed the way the circuit works is starting to make much more more sense now. I'll give the other thread a look-see and play around with fine tuning the circuit a little better.

        Thanks,
        lidrummer

        Comment


        • #5
          I like your piezo placement there John and the triple parallel piezo's is something I think Roland should've incorporate in their cymbals from day 1.

          Comment


          • #6
            Yes, I originally was just using 2 piezos, 1 for the edge and 1 for the bow/bell but it didn't seem like the response was very uniform across the playing surface, so I added the other 2 in parallel with the bow/bell piezo and mounted them so that when I wanted to play the bell sound I could hit with the shoulder of my stick right at the bell, just like playing a real cymbal. Seems to work well.

            I'm not too familiar with the Roland cymbals, other than playing the demo kits at the local music stores here. The CY-8 I think they stock at my local store for about $85. I guess that's not bad considering I've spent at least several times that on each real cymbal I own, but being inherently cheap I decided to go the DIY route, besides I can make an e-cymbal but not a bronze cymbal. Wait a minute, I took metalshop in high school! I know how to use a lathe. Maybe I can buy a furnace and some bronze and a big ol' hammer and...

            Comment


            • #7
              In my opinion, one of the biggest problems with the CY8 is the fact that it only contains one bow trigger piezo and has a hot spot right above it. I have thought about adding a couple more parallel piezo's to my CY8's to see how they respond but I might as well put that time into building a couple of my own e cymbals.

              Comment


              • #8
                John,

                I am going to breadboard up your Raper mod this weekend and give it a go on my crash cymbals. I also use the TD-3 module and was wondering if you might share your module settings for your cymbals. I hope that it would at least give me a starting point for adjustments.

                Thanks,
                lidrummer

                Comment


                • #9
                  I don't understand how you get 3 zones with only one jack output. It seems you connect the above 3 piezos directlty to the output. So it must be a 2 zone cymbal with choke, isn`t it?

                  Comment


                  • #10
                    I don't understand how you get 3 zones with only one jack output. It seems you connect the above 3 piezos directlty to the output. So it must be a 2 zone cymbal with choke, isn`t it?
                    The module (in this case the TD-3) takes care of it. Technically, the cymbal is 2-zone, but the TD-3 uses velocity sensing on the ride input to fire off either the bow or the bell sound depending on how hard one hits the cymbal.

                    lidrummer

                    Comment


                    • #11
                      Originally posted by lidrummer View Post
                      The module (in this case the TD-3) takes care of it. Technically, the cymbal is 2-zone, but the TD-3 uses velocity sensing on the ride input to fire off either the bow or the bell sound depending on how hard one hits the cymbal.

                      lidrummer
                      Exactly. That's why on the picture of my ride cymbal I show "hitting surfaces" directly over the piezos that I use for the bell. If you have a look at the pictures I originally posted, you'll see that if I play on the pie shaped area I get the bow sound, if I hit the pie shaped area harder I get the bell sound, or I can get the bell sound by hitting the circular surfaces with the shoulder of my stick, like a real cymbal. The edge sound I get by hitting firmly at the edge. So, 3 zones, although the module helps me cheat a bit by taking care of the bell/bow decision.

                      Comment


                      • #12
                        Originally posted by lidrummer View Post
                        John,

                        I am going to breadboard up your Raper mod this weekend and give it a go on my crash cymbals. I also use the TD-3 module and was wondering if you might share your module settings for your cymbals. I hope that it would at least give me a starting point for adjustments.

                        Thanks,
                        lidrummer
                        I haven't used the circuit for my crash cymbals, only for my ride. My crashes are single zone with choke. Since I'm still building my kit (conversion of one of my acoustic kits) I haven't played around with the sound settings too much on the ride cymbal. I think the pad setting is whatever is standard for kit #1. I did play with the "curve" control and found LD1 or LD2 settings to work well with the plastic cymbals with rubber playing surfaces. Seemed like a good combination of response and feel. Of course, your mileage may vary.

                        Comment


                        • #13
                          Damn it. Then you should have titled the thread "2 zone cymbal" instead
                          I was very surprised to find another design for 3 zone but it is 2 zone

                          I have made a real 3 zone ride, compatible with roland 3waytriggering modules. If you know Spanish language you can read the tutorial, if not, you can see the pictures (right click, see image) contained in the tutorial

                          http://www.batacas.com/portal/module...p?articleid=95

                          Comment


                          • #14
                            Originally posted by elrules View Post
                            Damn it. Then you should have titled the thread "2 zone cymbal" instead
                            I was very surprised to find another design for 3 zone but it is 2 zone

                            I have made a real 3 zone ride, compatible with roland 3waytriggering modules. If you know Spanish language you can read the tutorial, if not, you can see the pictures (right click, see image) contained in the tutorial

                            http://www.batacas.com/portal/module...p?articleid=95
                            I would love to be able to read this tutorial, the pics are too small to really see any detail.
                            sigpic

                            Comment


                            • #15
                              Originally posted by elrules View Post
                              Damn it. Then you should have titled the thread "2 zone cymbal" instead
                              I was very surprised to find another design for 3 zone but it is 2 zone

                              I have made a real 3 zone ride, compatible with roland 3waytriggering modules. If you know Spanish language you can read the tutorial, if not, you can see the pictures (right click, see image) contained in the tutorial

                              http://www.batacas.com/portal/module...p?articleid=95
                              elrules, that looks really good. It is taking the "trigger without a piezo" (just the switches) to the next level. I to have made switches like this for cymbals. Your design reminds me of the one I did, but better. Here's a link to my tutorial:
                              http://www.hellfiredrums.com/archives/67

                              If you want to turn this in to a two zone crash, just put the switch on top of the cymbal. Then it should work just like a CY-6.
                              alesisDRUMMER.com

                              Comment

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