Positional sensing, NOT A CLUE??

[Nisse Nas]

Hi all!
There are som postings on this board regarding positional sensing, all left unanswered, well does ANYBODY know HOW and WHEN it works, no one seems to know, yet Roland are using this as on of the u.s.p:s for selling the TD-8 and 10.

Nisse

[puttenvr]

It works on most snares. (i am not sure about the toms)

Positional sensing is when the sound near the rim of the drum is different (in general more open, ringy) than the sound in the centre of the drum (more dry).

How it works? the software inside the drum module "reads" on how many millimetres you put your drumstick on the head and chooses the proper sound (open, dry, half open etc)

[Arriguy]

I can only speak for the TD-10. It works on the snare and ride and if you have the TDW-1 expansion, it works on the toms as well.

[Nisse Nas]

I can understand what the result of positional sensing might be, but what I can´t figure out are how it works. If it only works on some snares sounds would it seem logical to assume that the second (rim tigger) might be to some help here, one Piezo just cant´t do the job.....or....if so, any suggetions?

Does anyone know how the midi implementation for positional sensing looks, is it possible to poke around with parameters like differnt note numbers for different positions etc in the TD-10/8.

BTW are the few internal snare sounds worth the positioal sensing feature, what do you think?


Nisse

[mfrzrdrum]

No it uses continuous controller messages, on the TD8 Controller number 16. If you run a computer program (Cakewalk or something)that will display MIDI cc messages, you can see it change as you hit from the center to the rim.

There was a pretty good guess as to how Roland used this to change the sample in a post a long while ago. Made good sense to me, but I couldn't explain it again. Something about looking for the peak of the wave and calculating a time delay....I don't know

Maybe someone remembers and could post a link

[jgerm]

Check out www.hartdynamics.com under the modules section. They have a pretty decent explaination of the different triggering technologies.

[FloridaDrummer]

The positional sensing is done using FSR triggers not piezo. Do a search on FSR's and especially read Feefer's posts, he has given some detailed explanations on them.

[FloridaDrummer]

Originally posted by feefer:

You mean the other way, right: piezo, not FSR? After all, Roland says the TDW-1 upgrade gives PS to the toms, too, and some of those contain mono-piezos.

Right, I should of reread my post. Sorry, I would of caught it the next time I read the post.

[Ken Taylor]

There are no 'Theories' as to how Roland achieves positional detection with its mesh pads.
A quick read of Rolands patent number 5920026
on the US patent office website. (There used to be a link on the V-drums site somewhere)
Reveals that frequency changes, as the head is struck from center to rim, which if you listen to your mesh pad when your Vdrums are turned off, you will be able to hear. Are measured by a simple software counter.
The first half wave of the signal is measured by the counter and as the half wave is wider in the center of the pad (frequency is lower) a longer count is measured telling the TD10 etc that the drum is struck in the center. A short first half wave means the counter number is small, which tells the 'brain' that the frequency is high so the strike is towards the Rim of the pad.
Dont take my word for it read it yourself.
There are also diagrams to illustrate this in the patent.

Ken.

[Ken Taylor]

Positional detection using rubber pads uses exactly the same system as with mesh.
Strike the PD9 with a stick and you will hear a frequency change from center to edge thats how its done! Its the same with V cymbals, you will hear the same frequency changes there too.
It aint Rocket science (I'd need a course in Physics for that!)

Ken.