Don't Pull That Trigger!




The Mechanics Of Triggering


1) Hit the pad
2) Drum module trigger input reads the trigger waveform





Fig. 1


Fig. 2




The Skinny:

Pads are fairly easy to make trigger accurately and precisely. Piezo-based acoustic triggers are much more difficult to make perform well. Pads and short acoustic sounds are much easier to make trigger well than acoustic sounds with long decays.

The first order of business is to cover some basic triggering terminology. Please note that there are a few differences between what each company calls the same setting. If there is an asterisk by a term, refer to Fig. 3 for the differences.

The height of a trigger waveform, measured in volts.

The vibration of the drum or pad being struck causing another trigger input to sound. This can be caused by sympathetic and mechanical vibrations from adjacent pads, or external loud sounds like stage monitors.

Double Trigger
One or more sounds sounding just after the initial (intended) pad or trigger hit.

A setting, related to mask time, that helps reduce false and double triggering due to additional peaks after the waveform’s initial peak, or trigger spike.

Mask Time*
The amount of time a module’s trigger input waits before it will react to another trigger signal. This setting helps filter out (mask) double triggering in the first 1-60ms (milliseconds) after a trigger signal is recognized by the trigger input. It is generally measured in milliseconds.

A measurement of time. One-second equals 1000 milliseconds. For reference, in air, sound travels at the rate of about one foot per millisecond.

Scan Time*
The amount of time after receiving a trigger signal that a sound module waits before reading the waveform amplitude to determine the volume (velocity) of a sound – measured in milliseconds.

A trigger setting used to balance out the varying voltage output levels of different acoustic triggers and pads.

The point below which a trigger waveform will not be recognized by a drum module’s trigger input.

Velocity Curve*
A setting used to alter how a drum module’s sound volume changes in relation to user input.

Waveform, Trigger Waveform
The representation of the voltage output of a drum trigger – shown in amplitude over time.


Fig. 3

Understanding Pad Types:

Rubber and Silicone, Mesh Heads, and FSR

Rubber and silicone pads essentially come in three types: single trigger, dual trigger, and three-way trigger. Although the technology used in most of these pads is very similar, you really should know which of the following pad types you are using. This will allow you to choose an exact or similar pad type in the trigger settings of the drum module. Doing this will give you settings that are a good starting point, thereby making it easier to get optimal trigger performance. Failing to set the pad type setting can make it nearly impossible to get good trigger performance.

Membrane-Switching Rubber Pads
Membrane-Switching pads have been around for decades, and are by far the most common type of pad. Most rubber and silicone dual-trigger pads are of this type. They use just one piezo to trigger both the head and the rim. The secret to getting the one sensor to trigger two zones is the use of a material called FSR – force-sensing resistors. FSR detects pressure, not vibration like a piezo, and is used on the rim of the pad. Fig. 4 shows an exploded view of a membrane-switching pad. The single piezo is mounted to the rigid plate on the underside of the pad’s rubber playing surface. My right hand is holding the FSR between the thumb and forefinger. As you can see, the FSR is a thin, flexible piece of plastic. A membrane-switching pad, like the one shown, can function in three different ways:

1) When you hit the center of the pad, it acts just like any other single-trigger piezo pad, and because of this, it can be used in any drum module.
2) To play the rim, you hit the rim and the center of the pad simultaneously. You see, the single piezo also functions as the sensor for the rim. There’s a circuit in the drum module that detects that the rim membrane is pressed (by the rimshot), and the module then sends the out sound assigned to the rim. To use the rim trigger on this type of pad, a drum module has to be designed to have this circuit – most do.
3) FSR also makes it possible to choke cymbals. Because the FSR in the rim senses pressure, the drum module can detect if the FSR has been pinched, and send out the data information needed choke off any sound playing that was triggered by that particular pad.

Membrane-switching technology is also used in three-way trigger pads like the ride cymbals pads from Roland and Yamaha, as well as some of Yamaha’s snare pads.

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Fig. 4

True Dual-Trigger, Mesh Pads

FSR Pads

Understanding Drum Modules: Types of Trigger Inputs


1) Single-Trigger Inputs

2) Membrane-Switching Inputs

3) True Dual-Trigger Inputs

4) FSR Inputs


Fig. 5


What You’ve Been Waiting For: Let’s Tweak Some Trigger Settings

Perhaps the best way to illustrate the functions of the different trigger settings is to take you through setting up an acoustic drum trigger. An acoustic trigger is much more difficult to get performing well than the common pad. If you can tweak a drum trigger into submission, any pad doesn’t stand a chance.

For this example I’m going to use an acoustic drum trigger on a tom. It is a single-zone trigger, so either a mono or stereo cable can be used to connect it to the module. I’ll be plugging it into a Roland TD-30 drum module, only because that’s what I have here in the studio. All the drum modules and trigger interfaces will have similar functions. Just to clarify, drum modules have built-in sounds; trigger interfaces do not.

Select the Trigger Type
After connecting the trigger, go into the trigger settings pages. Most modules “note chase,” so select the trigger input you want to edit by hitting the mounted tom. Then I select the trigger type, in this case RT10T. Setting the trigger type sets the trigger settings to values that work well with that acoustic trigger or pad type. (Fig. 6, Roland TD-30)


Fig. 6

Trigger types in a module will generally reference that manufacturer’s pads, not those of other manufacturer’s. When using pads with another manufacturer’s module, you’ll need to choose a trigger type that is similar in function. This is when it pays to know the subtleties of the different pad types. Starting off selecting an incompatible trigger or pad type can make it nearly impossible to get great triggering performance.

Set The Sensitivity
Next, set the sensitivity or gain of the trigger input. On the menu where input sensitivity is set, there is a graph (or text values) that shows the input level; it will change as you hit the drum softer and louder. To set the sensitivity, hit the drum as hard as you think you might in an actual performance. This is generally louder than you will hit it in a quiet room by yourself. Adjust the gain up or down so that the input sensitivity is peaking out just as the drum is hit the loudest. Then lower the sensitivity setting by one value to give a little cushion, in case the drum is hit even harder. (Fig. 7, Pearl Redbox)

Setting the sensitivity either too low or too high will limit the dynamic range of the input. If the level is too low, it’ll be difficult to get loud dynamics. If it’s too high, soft dynamics will be almost impossible. The sensitivity setting is extremely important. Take the time to get it right.


Fig. 7

Set The Threshold
Remember, threshold is the point at which a trigger signal is recognized by an input. The threshold is the first line of defense against false triggering. Begin by setting the threshold setting to “0,” its most sensitive, and then play the drum at the softest volume you’ll be playing. Slowly raise the threshold until the triggered sound begins to occasionally drop out. Then lower the threshold a value or two. Take note, the tendency will be to play the drum softer than you will in actual performance. Don’t be afraid of a few dropouts. Setting the threshold too low can cause unwanted double triggering and sympathetic triggering.

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Fig. 8, Alternate Mode DITI

Set The Mask Time
Mask time is an important setting. The mask time setting is mostly responsible for getting rid of double and false triggers. If possible, find out how your interface’s numeric values correspond to actual milliseconds, this will make setting this parameter a bit clearer. If not, you’ll just have to rely on your ear.


Fig. 9, Alternate Mode DITI

Take the mask time setting all the way down to “0,” then play the drum as fast as you will in actual performance. Raise the mask time setting until the double triggering is gone, or nearly gone. Next, continue to increase the value until some played notes don’t trigger. At this point, lower the setting a few notches.

For reference, the space between notes in a buzz roll is around 15ms. The space between flams is about 40—50ms. Generally, the snare will have the shortest mask time, the toms will have mask times that increase as the toms get bigger and lower in pitch. The kick drum can have a mask time of 50ms or more.

I use the headroom setting as a way to fine tune the mask time setting. For instance, if the drum is triggering fairly well, but occasionally there is a false or double trigger, I’ll gradually raise the headroom setting until it goes away.

Using Crosstalk
Crosstalk is the last setting to visit, and rather easy to tweak. If another input triggers when you strike a pad, gradually raise the crosstalk level on the offending input until the amount of crosstalk is either acceptable or gone. You may have to adjust this setting on more than one pad to get rid of all the crosstalk happening.

It’s possible that after following the method above, there still may be either note dropouts or double triggering. All I can say is make minor changes to the mask time, threshold, and sensitivity. It’s a balancing act. There are no fixed rules; you must experiment and tweak. You may even find that choosing another trigger type may magically work perfectly. (Fig. 10, Yamaha DTX900)


Fig. 10

Go Forth And Trigger!

Experimentation is the key to understanding trigger input settings. Remember, you can’t break anything by experimenting!

Mike Snyder loves drums, technology, and Lucy, his golden retriever. Contact him on Twitter: @drumbz or by email at .(JavaScript must be enabled to view this email address).