Seem to need Gain >7.0 for bass trigger

tehnick
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Re: Seem to need Gain >7.0 for bass trigger

Post by tehnick »

I'm on a converted acoustic kit with a 22" kick and it took a couple of weeks to get dialed in because of work but most of my triggering issues are resolved.

I had to mount my bar vertical instead of horizontal. The piezo would either be too hot for the slave and too cold for the main, or vice versa. The reason because is that the piezo had to be on one side or the other of the set of beaters. When going vertical, my foam pad is centered and the piezo is slightly above where both beaters strike. Sound output is consistent between both strikes.

In terms of the gain, sounds like a bad piezo if I had to blame anything else. If the kit is designed in a way that you can swap the piezos from one bar to another I'd recommend taking a piezo from a drum that works good and installing it on the bridge of the kick and trying that. There's also a chance the piezo isn't high enough above the bearing edge or that yoye head tension is too low so your hits are registering poorly because the surface contact is bad.
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Rob
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Re: Seem to need Gain >7.0 for bass trigger

Post by Rob »

MachRider wrote:I'm not refusing to investigate but I'm not going to start ripping foam off my triggers just because somebody thinks I should
Agreed. Don't do anything that is going to damage your kick.

But pulling off the drum head and inspecting things is pretty low risk. You might find that the head is not making proper contact with the sensor.

For the screenshot, use the max gain setting.
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Rob
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Re: Seem to need Gain >7.0 for bass trigger

Post by Rob »

You would need a gain of 40 for that signal. Something is really wrong.
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Rob
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Re: Seem to need Gain >7.0 for bass trigger

Post by Rob »

You're using a splitter cable? Can you send me a link to the one you are using?
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Rob
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Re: Seem to need Gain >7.0 for bass trigger

Post by Rob »

Everything looks in order. Is it possible to adjust the crossbar so that the foam is pressed more tightly against the beater head?
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Rob
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Re: Seem to need Gain >7.0 for bass trigger

Post by Rob »

If, after making whatever adjustments you are able to make, you still can't get a full range from the pad, contact me via technical support and we'll measure exactly how much gain you would need and I'll see about making that change for version 1.2. I would expect to have a version 1.2 beta ready in about a month.
Mylo
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Re: Seem to need Gain >7.0 for bass trigger

Post by Mylo »

Is the foam used in the bass too soft? That bar trigger looks no different than all the other bar triggers out there. Piezo transducers are simple devices, we all know that. They flex (I use that word cautiously as it is more of an agitation than a flex) and create an electrical signal. The foam is there to protect the piezo from direct hits so it needs to be soft. But at the same time it has to be stiff enough not to absorb all the hit. Some of the velocity from the hit has to reach the piezo.

Can you take the batter head off and hit the foam or maybe even the piezo directly with your finger and see if you get a better response?

How is the piezo attached to the mounting plate?

See this post on vdrums: https://www.vdrums.com/forum/advanced/d ... post203362

The key take away is that mounting the piezo using a thicker two-sided tape that covers about 2/3 of the disc tends to make the piezo more reactive. I’ve seen this play out in my own experiments.
perceval
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Re: Seem to need Gain >7.0 for bass trigger

Post by perceval »

vince,

you could try adding a thin layer of neoprene or mini cell foam on top of the foam cone/column to add more pressure to the piezo.

I have a 22" half kick drum, and I had never any trouble using it with a simple crossbar piezo with the eDRUMin.
perceval
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Re: Seem to need Gain >7.0 for bass trigger

Post by perceval »

I have the uber most respect for Dave,

He seems a genuine guy, and always kept his cool when he was attacked by a competitor.

His drums are gorgeous, and with the years of experience he has, I'm sure he knows how to wire a piezo. :)

No one is blaming Dave here.

What we are pointing out is that it might (or not) be a bad piezo. It happens. I'm sure Dave buys them in boxed quantities. Out of 100, there might be one that got away from QC at the factory.
It's just one of the factors that might be causing the problem.

Many of us have also been down that road... identifying the gremlin in the path and fixing it.
Sometimes, it's straight forward. Sometimes, it's hair pulling!

It's no fun, I know.
Again, we are not blaming Dave, nor his design.
But along the path, there is something wrong, and we are just throwing ideas around for you to look into, because many of us have done DIY conversions too, and I also have a kick drum cross bar mounted that I used before with no problem with the eDRUMin.

I'll see if I can dig it out from storage, put it back and find out if the gain of 7 is enough for me.

I have two sizes of piezos here, 35 and 26mm. I'll test them both and report later.
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Rob
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Re: Seem to need Gain >7.0 for bass trigger

Post by Rob »

MachRider,

It's fairly easy for me to increase the gain, but increasing the maximum gain is not going to have any effect on the physics at play here. I'll try to explain.

When a person hits their drum, eDRUMin measures of voltage between 1 and 1024. Most pads will use up this entire voltage range, giving them 1024 different possible measurements. Let's say a particularly weak pad only produces a voltage between 1 and 256. This pad will only be capable of 256 different possible measurements. That's not terribly bad. MIDI only offers 128 velocities, so as long as we don't apply any radical velocity curve, it should sound fine.

In the case of your drum, it's producing a voltage range (guessing because we haven't measured) between 1 and 40. I think you should be able to see the heart of the problem here. With only 40 possible measurements, you are getting way less resolution than MIDI provides.

As I said, I can increase the gain for you, but doing that will not result in more dynamics and resolution. The only way to fix that, is to get your drum to generate a stronger voltage.

All that being said, I think I would be comfortable doubling the maximum gain to 14. So if you can find a way to double the strength of your signal, you should get usable results with a gain of 14.

Robert
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