Positional sensing testing

[rockdude]

Updated the firmware with an additional Positional setting and fixed a bug with piezo/switch pads which I accidentally introduced in the previous version.

More settings! Great work dmitri! I almost finished my 14" DIY A to E snare yesterday. I've also added a pot to it to reduce sensitivity and tweaked it's settings in MegaDrum so it should be ready for positional sensing testing today.
(I experienced some issues though when fiddling with my snare. When striking it hard so that it's close to peak signal, it seems to generate more notes than just the snare note. Anyway, I'll start another thread describing this issue more in detail later since it has nothing to do with positional sensing.)

Keep up the good work!

[samdrum]

The news about positional sensing being added to megadrum is the best news in months!

There has been some discussion in the megadrum and Vdrums forum about the preferred shell size. Back then the conclusion was that head type was more important than shell size, see:
viewtopic.php?f=3&t=760&p=8853&hilit=samdrum#p8853

Dimitiri, you already proved that shell size is important (the bigger the better), but did your experiments also include different head types? I would be interested in hearing what type of heads work best.

Please note that your work on positional sensing is highly appreciated!!

[dmitri]

I cannot comment on head types. The pads I tested with have manufacturers own heads and I have no idea what they are made of.

[The3D]

hello all, i'm testing the positional sensing feature on my megadrum (you are the man dmitri) on my DIY 14" snare. It looks like i'm unable to get it working correctly. The "pointer" in debug mode always stay near the middle of the interval delimited by the positionallow and high (if i have got it correctly) and it barely moves. The pad is positive wired (alesis wiring style) but i think that it could be too hot. These are my current snare settings:

HighLevel: 854
Function: log4
Gain: 3
Threshold: 18

When i move the stick from center to rim, the numbers the debug screen are approximately in this range: 0-4 the first, 12-18 for the second number, 18-24 the third, regardless of the position of the stick. Should i "cool" my pad?

bye

[rockdude]

hello all, i'm testing the positional sensing feature on my megadrum (you are the man dmitri) on my DIY 14" snare. It looks like i'm unable to get it working correctly. The "pointer" in debug mode always stay near the middle of the interval delimited by the positionallow and high (if i have got it correctly) and it barely moves. The pad is positive wired (alesis wiring style) but i think that it could be too hot. These are my current snare settings:

HighLevel: 854
Function: log4
Gain: 3
Threshold: 18

When i move the stick from center to rim, the numbers the debug screen are approximately in this range: 0-4 the first, 12-18 for the second number, 18-24 the third, regardless of the position of the stick. Should i "cool" my pad?

bye

If your snare is too hot you shouldn't have Gain:3
Try setting it to 0 instead and increase HighLevel.
I'm absolutely no expert in MegaDrum settings, but that's what I would do first.

[The3D]

hello all, i'm testing the positional sensing feature on my megadrum (you are the man dmitri) on my DIY 14" snare. It looks like i'm unable to get it working correctly. The "pointer" in debug mode always stay near the middle of the interval delimited by the positionallow and high (if i have got it correctly) and it barely moves. The pad is positive wired (alesis wiring style) but i think that it could be too hot. These are my current snare settings:

HighLevel: 854
Function: log4
Gain: 3
Threshold: 18

When i move the stick from center to rim, the numbers the debug screen are approximately in this range: 0-4 the first, 12-18 for the second number, 18-24 the third, regardless of the position of the stick. Should i "cool" my pad?

bye

If your snare is too hot you shouldn't have Gain:3
Try setting it to 0 instead and increase HighLevel.
I'm absolutely no expert in MegaDrum settings, but that's what I would do first.

thanks for the answer! nothing changes if i lower the gain to 0 and increase maxLevel. That values in debug screen always fall in the range said before.

[The3D]

hello all, i'm testing the positional sensing feature on my megadrum (you are the man dmitri) on my DIY 14" snare. It looks like i'm unable to get it working correctly. The "pointer" in debug mode always stay near the middle of the interval delimited by the positionallow and high (if i have got it correctly) and it barely moves. The pad is positive wired (alesis wiring style) but i think that it could be too hot. These are my current snare settings:

HighLevel: 854
Function: log4
Gain: 3
Threshold: 18

When i move the stick from center to rim, the numbers the debug screen are approximately in this range: 0-4 the first, 12-18 for the second number, 18-24 the third, regardless of the position of the stick. Should i "cool" my pad?

bye

If your snare is too hot you shouldn't have Gain:3
Try setting it to 0 instead and increase HighLevel.
I'm absolutely no expert in MegaDrum settings, but that's what I would do first.

thanks for the answer! nothing changes if i lower the gain to 0 and increase maxLevel. That values in debug screen always fall in the range said before.

Ah of course, my poistionalLow and high values: 11 24

[rockdude]

I have to try this myself. I also have a DIY 14" snare with Alesis wiring. Maybe we do need that precision rectifier after all. I'll post here when I've tried this firmware too.

[The3D]

i don't know the algorithm dmitri implemented, anyway might be that positional sensing works before any module correction of the signal generated by the piezo. If it works in this way:

hit on the pad -> positional sensing detection -> module processing/correction (function, gain etc etc) -> midi note

a hot pad would'nt work with PS regardless of the settings of the module

i consider my pad a hot pad (since i have a pretty high highlevel value and fairly low gain) but i could be totally wrong.

[dmitri]

I've tested in on Pintech (positive first half wave) with a voltage divider and without a rectifier. Although less accurate than with a rectifier it does work with Positional set to 2, PositionalLow - 12, PositionalHi - 18.
If the pad is too hot, the positional sensing will not work properly as I pointed out in the first post.