Drum Triggers...how?

  • Thread starter Thread starter casualtyfigure
  • Start date Start date
C

casualtyfigure

New member
*not sure where to post this question. but...


How do drum triggers work...?
(mechanically)

As in, what happens inside the trigger.
(not how do i USE the trigger)

Im sure its simpler than i think.



I want to use them for possible experimental purposes.
Ive seen them used before. In various ways.

Just a curiosity thats hit me recently.

thanks for any info.
 
I'm pretty sure they work on the same principles of sensing vibration.
 
They basically consist of a piezo transducer which is mounted against the drum head. It turns the vibration from a drum hit into an electrical signal. That signal is used to trigger a sample.
 
metalhead28 said:
They basically consist of a piezo transducer which is mounted against the drum head. It turns the vibration from a drum hit into an electrical signal. That signal is used to trigger a sample.
Click to expand...



Its based on vibration...

the transducer, will it work on anything that provides vibration?
(assuming yes.)


So it sends the vibration to the "brain"...

Does it send any info, based on how its hit, or its is just
static saying..."hey...play something now."
err....
will it pick up the differences between gently tapping,
and bashing with a hammer.
(im thinking- static.)


or is that what the brain does...
decides what to play based on the vibration?


I want to put them on random objects,and see whats what.

I did see the "home made" trigger/transducer things.
I may go that route...its cheaper.

thanks for the info.

im probably going to mess around with this stuff this weekend or something.
 
A piezo transducer is basically a crystal mic element. Also, you can wire it backwards for a simple speaker. They're found all over the place in toys, musical birthday cards, watches, computers, etc. Look like a 1 or 2 inch metal disc with a couple of wires soldered to the back.

When you apply a signal to the crystal, it makes the disc vibrate, and acts as a speaker. Conversely you can wire it into a preamp/amp and sense vibrations in the air or a surface like a microphone.

The "brain" of an electronic drumset or drum module (think Alesis D4) has trigger inputs for signals from these and uses them as a switch to trigger off a sample. The relatively newer ones have a threshold under which they won't trigger (so hitting a nearby trigger doesn't cause unwanted crosstalk) and can detect differences in signal to vary the volume or other characteristics of the sample.

You should be able to Google "drum trigger construction" and find a bunch of projects that others have done. Radio Shack is an easy place to find piezo transducers for cheap experimentation. I've seen others make drum pads from plywood with a sheet of rubber on top (essentially the guts of a Simmons pad) and recall a friend of a friend placing mics inside pumpkins for a Halloween show, that triggered a Roland brain. He played the pumpkins by smacking the sides with an open hand. In fact, Mick Fleetwood had a trigger suit built for a tour in the late '80s that I recall reading about...

Good luck!
 
Drum triggers and modules are simple.

Each trigger is a mic that senses how hard you hit it. The drum module/brain converts the sensitivity to a MIDI velocity and wham, you have a midi controller.

The chip in the drum brain that converts the analog signal from the piezo to a MIDI signal costs about 5 bucks.
 
Aside from the Alesis D4 what are some other drum brains that one could dip their foot in the pool with. I don't really want to buy a freaking $2000 spaceship drumset. I just want a brain that has 1/4" ins and a few reasonably cheesey built in sounds.
 
I saw a cheap drum pad kit at Sams club for $300. I'm sure the brain was cheesey.

The Alesis D4 and DM5 are the cheap brains. The Ddrum, Spacemuffins, Roland brains are much more expensive.
 
so i went to radioshack, and bought a transducer and some 1/4 jacks.
Im going to see is there is something interesting that i can piece together.

Does anyone else know of any more DIY project sites?
With weird devices?

I already do circuitbending.

but i was wondering about anything else out there.

I may post another thread on this.
I like DIY.

Thanks for all of your help.
(im kind of looking at the Alesis stuff.)
 
if you are gonna do quite a few triggers, buy the piezo elements in bulk....you'll get a better price and wont curse as much when you ruin one.....

ive gotten some from Mouser before......
 
casualtyfigure said:
*not sure where to post this question. but...


How do drum triggers work...?
(mechanically)

As in, what happens inside the trigger.
(not how do i USE the trigger)

Im sure its simpler than i think.



I want to use them for possible experimental purposes.
Ive seen them used before. In various ways.

Just a curiosity thats hit me recently.

thanks for any info.
Click to expand...

The trigger sends out a low voltage usually less than 10 millivolts. This voltage can and does vary depending on how forceful the drum hit. The input to the module is hyper-sensitive and can detect that low voltage. A change in voltage regulates how loud the sample gets played from the module. That's all there is to it!

A low voltage from anything else will also trigger the module. Sometimes I run the aux send from my mixer to the input of my Roland module and re-trigger a kick or snare coming from a live microphone. I just adjust the level of the aux send to satisfy the input sensitivity.

Enjoy!

RawDepth
 
From what I understand, the signal voltage from the piezo goes to an analog to digital converter and is then interpreted as midi info.
 
im actually sitting down to do this right now...

My idea, is to wire up the piezo, attach it to a guitar...
(i dont have my bass handy...)

well attach it to where the most vibration is...
and run it through some HEAVY effects.

Of course, this will need ALOT of testing.


It all comes from a performance i saw of an acquaintance.
He had a sheet of metal...TONS of feedback.
all he did was beat and pound this piece of sheet metal.
and it changed the pitch and distorted it like mad.

i asked him what he used...all he said was "its just a drum trigger attached to
the inside." So , i know that he had more, the feedback was SO piercing.
BUt...that will come with experimentation.

I dont know really...this may not work how i expect, at all.

And since i only have a small, almost embarassing electro project setup.
i dont have quite as many resources as id probably need.
I mostly make weird experimental crap anyways...
Usually just make noise, then sample it.

anyways...


again thanks for all of your help!!
 
casualtyfigure, you need something to convert the audio signal to midi information.

the signal from the piezo is only an ac audio signal. something has to convert the ac audio signal to digital information (analog to digital converter), something has to translate the digital information to midi information (midi processor?...), and something has to be in place to accept the midi information and generate sound (sound module or synth).

wiring a piezo to a guitar won't get you any where. you're just adding a crappy pickup to a guitar. :D an ac signal comes out of a piezo. an ac signal comes out of a guitar pickup.
 
TravisinFlorida said:
casualtyfigure, you need something to convert the audio signal to midi information.

the signal from the piezo is only an ac audio signal. something has to convert the ac audio signal to digital information (analog to digital converter), something has to translate the digital information to midi information (midi processor?...), and something has to be in place to accept the midi information and generate sound (sound module or synth).

wiring a piezo to a guitar won't get you any where. you're just adding a crappy pickup to a guitar. :D an ac signal comes out of a piezo. an ac signal comes out of a guitar pickup.
Click to expand...


wow...i really appreciate the info!

I was just going for something simple to experiment with.
Something new, different err whatever.
thanks so much though!!!

So i went ahead and played with it.
i hooked it up as you would anything.
It gave me a bunch of feedback. Buzzes and hums.
I tapped on it a bit to see what it would do. It just
mirrored the taps i was doing. So, i added a bit of distortion.
and effect crap. As well as a feedback loop through my mixer,
at about 40%.
That actually really helped get a bit more sound out of it.
that and a slight bit of decimation.

i was getting sound just by touching it.
i tapped on it like it was a tiny little drum, sounded ok.
I proceeded to hum on it. It amplified my voice/hum.
So i shoved in onto my throat, (i have a circle imprinted on it now)
and added a tri-octave effect. It sounded pretty f'd up.
I liked it. So i started screaming with my mouth closed.
It sounded kind of evil.

I dont see myself using this except for recording something horror related.
Ambient-ish.

thanks for all of the info.
I seriously appreciate it.
 
TravisinFlorida said:
From what I understand, the signal voltage from the piezo goes to an analog to digital converter and is then interpreted as midi info.
Click to expand...
No, an analog to digital converter has nothing to do with midi. A drum brain works, more or less, like a noise gate. When the signal passes the threshold, it triggers the sound and/or the midi note. There is no AD conversion.
 
Farview said:
No, an analog to digital converter has nothing to do with midi. A drum brain works, more or less, like a noise gate. When the signal passes the threshold, it triggers the sound and/or the midi note. There is no AD conversion.
Click to expand...

I think there is. :D

http://www.edrum.info/theory.html

How else can audio be translated to midi velocity levels? Explain please. I'd like to understand this stuff more myself.
 
TravisinFlorida said:
I think there is. :D

http://www.edrum.info/theory.html

How else can audio be translated to midi velocity levels? Explain please. I'd like to understand this stuff more myself.
Click to expand...

You guys are arguing over apples and oranges.

That website shows a hobby project based on the old school way the edrum systems used to work. Back in the 70's and 80's you needed all that crap in your system to trigger a midi instrument. Modern day modules have come a long way and are much simpler. They basically just play back a recorded sample when the voltage from the trigger goes over a threashold like Farview explained.

Yes, home hobbyists can still enjoy tinkering with those methods if they want. It is still the cheapest way to make edrums work without buying an expensive module. So, go ahead and build and experiment till your heart is content. :)

There is no need to murder each other over how it should be done.

RawDepth
 
You must log in or register to reply here.
Back
Top