Stompboxes of the percussive variety

[parmalee]

Peter Sesselman, inventor of the Puck'n Stompa stompbox and many other fine products, recently introduced a new variation to his line of hockey puck-based stompboxes--the PS-808 Long Bass Stomp:

The long stomp in isolation can be heard at 1:59.

Somewhat unique in the passive/non-sample-based (or over-damped filter/oscillator) stompbox world, Sesselman's stomps employ the transducer-with-counterweight (to lower the resonant frequency) technique, thereby allowing one to use whatever sort of enclosure one desires, as such will not really affect the sound.  Presumably the PS-808 employs a similar technique, but... how?  The decay is just over a full second and I can't figure how one could possibly achieve such simply by prodding a speaker.

Any ideas?

[stallik]

Peter states that they've redesigned the transducers so that they can be built entirely in house. This apparently allows them to mess with frequencies and time so perhaps they're now different to the speaker with weight. Or maybe that's just marketing..

Been messing with midi foot drums over the past few months and while I can get them to sound good with finger taps, a good foot actuated trigger eludes me. My Peterman bass stompa works really well - perhaps I should just buy more of the things.

Thanks for highlighting  this new version

[ElectricDruid]

Couldn't you just use the stompy bit to provide a trigger to a standard analog drum circuit? Most of those react differently depending on the amplitude and/or length of the trigger, so you still get some dynamics - and you could tweak things so you get *more* dynamics, if the basic design doesn't have enough. But analog drums often have several parameters that you can vary (pitch, decay, balance of different aspects of the sound, etc etc).

Given the name PS-808, when I saw this thing, I assumed it was an 808 kick circuit in a foot-triggered stompbox form.

[parmalee]

Couldn't you just use the stompy bit to provide a trigger to a standard analog drum circuit? Most of those react differently depending on the amplitude and/or length of the trigger, so you still get some dynamics - and you could tweak things so you get *more* dynamics, if the basic design doesn't have enough. But analog drums often have several parameters that you can vary (pitch, decay, balance of different aspects of the sound, etc etc).

Sure, you could do that, but that takes all the fun out of trying to make it work passively.  Of course, you still have to power the amp, so...

I've played around with both approaches, but lately I've been getting a lot more out of the weighted-speaker-cone (plus low z to high z transformer) in a hockey puck method.  Shamefully, I've pretty much copied Peter's method entirely--at least, so far as I can tell.  Mine sound pretty near identical to the Puck'n Stompa, so I figure I've gotta be doing much the same thing.

I've also made a couple of shaker plus piezo in a hockey puck dealies for a snare-ish sound.  Overall, with the bass and shaker combo, I'm pretty satisfied.  And an added bonus:  I got to play around with forstner drill bits - for boring out the vulcanized rubber hockey pucks - which I somehow had never encountered before.

As far as the analog circuits go, my favorite has always been Craig Anderton's Hip Bass Drum circuit - schematic here.  It's a fairly basic/minimal circuit, but you can get quite a variety of sounds from it.

[parmalee]

Peter states that they've redesigned the transducers so that they can be built entirely in house. This apparently allows them to mess with frequencies and time so perhaps they're now different to the speaker with weight. Or maybe that's just marketing..

Been messing with midi foot drums over the past few months and while I can get them to sound good with finger taps, a good foot actuated trigger eludes me. My Peterman bass stompa works really well - perhaps I should just buy more of the things.

Thanks for highlighting  this new version

Yeah, I've found that making a reliable trigger is not as straightforward as one might think.  I've played around with some code I encountered somewhere on the interwebs (I'll try to find the link, if you're interested) that measures velocity with piezos (also not as straightforward as one might think), and honestly had more success with that than with making a consistently reliable foot actuated trigger.

Have you encountered this one before?

I was rather impressed by his consummate diy approach - and here's a "making of" video which I rather enjoyed.

[stallik]

I'm using Deadastro's Nano-8 midi drums connected to an ancient Roland sound canvas box. The system uses piezo disks and Deadastro supplies the code which implements velocity etc. it works very well on my system . I can tap a trigger with my finger and go from gentle tapping to whacking the hell out of it and hear the expected result. The nearest I've got to that with my feet is to hold a drumstick between my toes and hit the trigger with that. Unfortunately, that gives me cramp pretty quick.

I've built 10 or so foot to stick contraptions. Some work better than others but none give me the sound/feel/ease of use that I'm after. Problem is that after a few hours of playing about, I see something shiny on my pedalboard and get distracted

[duck_arse]

The long stomp in isolation can be heard at 1:59.

Code Select Expand

[url=http://"https://youtu.be/ngED29mmbL8?t=119"]1:59.[/url]

As far as the analog circuits go, my favorite has always been Craig Anderton's Hip Bass Drum circuit - schematic here.  It's a fairly basic/minimal circuit, but you can get quite a variety of sounds from it.

Code Select Expand

[url=http://"https://electro-music.com/forum/topic-28447.html"]

your links aren't workable - too much http. at least.

[parmalee]

your links aren't workable - too much http. at least.

They should be working now--thanks for pointing that out.

[iainpunk]

i was looking in to building 8 tuneable kicks so i can play bass lines with them. i heard that happening in some hiphop subgenres, and really like that aspect of those songs.

cheers

[Rob Strand]

Couldn't you just use the stompy bit to provide a trigger to a standard analog drum circuit? Most of those react differently depending on the amplitude and/or length of the trigger, so you still get some dynamics - and you could tweak things so you get *more* dynamics, if the basic design doesn't have enough. But analog drums often have several parameters that you can vary (pitch, decay, balance of different aspects of the sound, etc etc).

Given the name PS-808, when I saw this thing, I assumed it was an 808 kick circuit in a foot-triggered stompbox form.

The touch sensitivity is where transducers and micro's help.

The basic drum can be done with a simple circuit,



This one uses touch pads but it can be modified to use switches.   The touch pads probably won't work through shoes.  I can't remember if it was touch sensitive at all, got my doubts.   I'm sure a similar version of the project came out in the 60's.   

The other angle is one of those "stompboxes", they have a sensor.   The piezo sensors look interesting.

<link screwed up>

[Hobs]

Could they be using something like this?

https://www.digikey.com/en/products/detail/te-connectivity-measurement-specialties/1005447-1/279647

[Rob Strand]

Could they be using something like this?

https://www.digikey.com/en/products/detail/te-connectivity-measurement-specialties/1005447-1/279647

I was thinking of the common cheap-ass disc sensors,
https://www.piezoelements.com/piezo-diaphragm/external-drive-piezo-diaphram/disk-type-piezo-sensor-element.html

[anotherjim]

Piezo can just be a contact mic reproducing the sound of the box although EQ would be helpful. I've seen it done with a Boss graphic pedal doing the job. Feedback and isolation are an issue though for stage volume use.

Almost any simple trigger system is prone to false triggering. Try using a contact mic on a kick drum to trigger a V-drum. It works, but anything that makes the drum resonate also works! Sensitivity needs tweaking for every situation.

What's needed is a trigger that unambiguously senses the players stomping for timing and velocity.

[amptramp]

If you want a drum synthesizer project, it is the cover story on the May 1980 issue of Radio-Electronics:

https://worldradiohistory.com/Archive-Radio-Electronics/80s/1980/Radio-Electronics-1980-05.pdf

The article begins on page 49.

[iainpunk]

The basic drum can be done with a simple circuit,



This one uses touch pads but it can be modified to use switches.   The touch pads probably won't work through shoes.  I can't remember if it was touch sensitive at all, got my doubts.   I'm sure a similar version of the project came out in the 60's.   

The other angle is one of those "stompboxes", they have a sensor.   The piezo sensors look interesting.

<link screwed up>

it uses the ''flying lead'' on the right side of the circuit as a switch on the touch pads. basically the touch pads can be replaced by switches if you want to. keeping them in contact for to long of a time will double trigger, once when touching and one when releasing.

cheers

[ElectricDruid]

What's needed is a trigger that unambiguously senses the players stomping for timing and velocity.

Watching the Woodpecker "electromagnetic stompbox" video posted by Parmalee earlier suggests that these passive pedals use a coil of wire and presumably some spring-mounted magnet hovering inside it. Then it's just a question of putting soft squishy feet under the box so that it can move when you stomp it. You stamp, the magnet wobbles about, the coil picks up the movement, bingo! Very much like slapping the side of the amp and making the reverb spring twang, in fact. The pitch you get will depend on the resonant frequency of the spring-mounted magnet and will be entirely physical, depending on the weight of the magnet and the stiffness of the spring mount and so on. The output coil is a guitar pickup, more or less, except that instead of moving a string inside the magnetic field, we can move the whole field.

You could use a similar thing as a "step one" to make a trigger generator. Designing an envelope follower circuit is a *lot* easier if you're only dealing with a single note and you know the frequency of that note ahead of time. For such a purpose, I'd want to have a spring-magnet-coil system which produced a fairly high pitch (so not a bass drum BOOOM but more of a PING!) to reduce latency in the detection and to make ripple filtering much easier. Then the output would be a short envelope, complete with as much dynamics as you can get out of your sensor (which should be quite a bit, I'd guess).

Once you've got a dynamic trigger like that, you can build as complex a synth circuit to follow it as you like. The sky's the limit.

[parmalee]

Watching the Woodpecker "electromagnetic stompbox" video posted by Parmalee earlier suggests that these passive pedals use a coil of wire and presumably some spring-mounted magnet hovering inside it. Then it's just a question of putting soft squishy feet under the box so that it can move when you stomp it. You stamp, the magnet wobbles about, the coil picks up the movement, bingo! Very much like slapping the side of the amp and making the reverb spring twang, in fact. The pitch you get will depend on the resonant frequency of the spring-mounted magnet and will be entirely physical, depending on the weight of the magnet and the stiffness of the spring mount and so on. The output coil is a guitar pickup, more or less, except that instead of moving a string inside the magnetic field, we can move the whole field.

Hence the sound in that device, and Peter Sesselman's stomps, is determined almost entirely by what's inside the enclosure, irrespective of whatever one chooses for the enclosure itself.  I've never quite gotten the appeal of the stomps which use a piezo disc as both trigger and sound producer--unless you've got a decent sized box or board or whatever, the resonant frequency is unlikely to be sufficiently low enough to sound like a kick drum.

You could use a similar thing as a "step one" to make a trigger generator. Designing an envelope follower circuit is a *lot* easier if you're only dealing with a single note and you know the frequency of that note ahead of time. For such a purpose, I'd want to have a spring-magnet-coil system which produced a fairly high pitch (so not a bass drum BOOOM but more of a PING!) to reduce latency in the detection and to make ripple filtering much easier. Then the output would be a short envelope, complete with as much dynamics as you can get out of your sensor (which should be quite a bit, I'd guess).

Once you've got a dynamic trigger like that, you can build as complex a synth circuit to follow it as you like. The sky's the limit.

Interestingly, every single stompbox I've come across that triggers an electronic sound source uses samples, rather than a synthesized drum sound.  And they're all somewhat pricey, too boot--like the Roland SPD:One.  Not crazy expensive, perhaps, but for what it does?  I dunno.

I don't really get that.  With a decent synth circuit, one can control multiple parameters; whereas with the sampled drums, you can vary amplitude and maybe pitch, but not much else.

[Rob Strand]

it uses the ''flying lead'' on the right side of the circuit as a switch on the touch pads. basically the touch pads can be replaced by switches if you want to. keeping them in contact for to long of a time will double trigger, once when touching and one when releasing.

cheers

It should work.   IIRC the original intent was if there wasn't enough stray hum to kick the oscillator you had to hold on to the clip.  That generated a DC pulse to kick the oscillator.   I can't remember if the original article mentioned switches but it's no different to holding the clip.   Worst case would be to increase the series resistance to emulate resistance of the human body.

[amptramp]

If you want some mathematical correctness for a drum skin, its resonances will follow a Bessel function of the zeroth order.  You have an initial resonant frequency where all the drum skin moves inward, then a next one where part of it moves inward and the inner part closer to the centre moves back ward towards the drumstick and so on for further orders of resonance.  These resonant frequencies are nowhere near integer multiples like harmonics.  The resonances of a Bessel function of the zeroth order are:

2.405
5.520
8.653
11.791
14.931
18.071
21.212

etc.

You can do a brute force synthesis by using these frequencies as the output multiplied by the amplitude of the function at the radius where the drumstick hits the drum.  Most drummers hit the drum near the edge and the first resonance is usually damped into oblivion but the rest of the frequencies are there.  Only long drums like tams have any output at the 2.405 fundamental.

[anotherjim]

Don't the real-deal foot stompers want it to sound like a porch board though? That is, not a drum.