Author Topic: Reflection plate design discussion  (Read 11292 times)

Offline rockdude

Reflection plate design discussion
« on: August 18, 2009, 02:07:11 AM »
Hi!

I posted a topic about reflection plate designs at the vdrums forum, but since I'm an Alesis Trigger IO user I might as well post some excerpt from it here and continue the discussion.
(Cheapthrill and Hellfire: I know you two have already read and answered, but I hope you forgive me for posting it here too and we can continue the discussion here since there's lot's of Alesis users here.)

Well here we go:

Quote
I was searching and reading about reflection plate designs and I might have got this wrong, but it looks like the piezo is facing down with the ceramics pointing away from the head on reflection plate designs (at least that is what it looks like on the pictures)....compared to a trigger cone where the piezos ceramics is facing up towards the drumhead.

Am I right and if so, why is it positioned this way?

Example:
http://www.wastingwebspace.com/Html%20Pages/YamahaDrumsPage.htm
http://www.wastingwebspace.com/Html%20Pages/ClonezDrumsPage.htm
http://www.wastingwebspace.com/Html%20Pages/ChameleonKick.htm

The below link is a concept drawing which I and Hellfire discussed some time ago. A three zone reflection plate design. I never asked about the ceramics facing up or down on this one though. If you're reading this Hellfire, you're very welcome to discuss this design again.
http://www.hellfiredrums.com/archives/239

In summary the answers were:
Quote
Reflection plates always involve the ceramic (of the piezo) facing away from the head (and are also glued onto the surface rather than adhered with foam tape).

Quote
The piezo elements are mount in the traditional refection plate manner. The refection plate type triggering came first, so a better question would be why does Roland mount the piezo elements upside down?  ;D

I then posted the following:

Quote
Thanks for all replies. I'll give the reflection plate a go. My current "traditional" crossbar design with a center trigger cone creates a hotzone right in the center. Not good since that's the place I'm striking almost all the time.

I'm hoping a well built reflection plate design can spread the force applied to the drum more even over the drumhead and therefore reducing potential hotspot areas. Is this a possible scenario or are hotspot zones prone to appear in a reflection plate as well? (I'm using Alesis Trigger IO)

My question still remains...Is there any difference between having the ceramics facing up or down? At first I thought that since the ceramics are the most sensitive area, it has to face the drumhead. I guess the vibrations will travel through either way. I guess both variations are are supposed to protect the piezo wires. The Roland style trigger would break more easily if it was facing towards the often hard mounting plate...and the piezo in a reflection plate design would break more easily if the ceramics would face the trigger plate. I don't know if it's as simple as that or if there's something more involved.

So now let's continue the discussion everyone!  :)

« Last Edit: August 18, 2009, 05:36:39 AM by rockdude »

Re: Relection plate design discussion
« Reply #1 on: August 18, 2009, 04:03:27 AM »
Since it's my first day I might as well jump right in and let you know you'll need to expand your links again as you've copied them in shortened form. :)

Offline rockdude

Re: Relection plate design discussion
« Reply #2 on: August 18, 2009, 05:24:57 AM »
Since it's my first day I might as well jump right in and let you know you'll need to expand your links again as you've copied them in shortened form. :)

Thanks for pointing that out. The links should work now :)

Offline rockdude

Re: Reflection plate design discussion
« Reply #3 on: August 19, 2009, 12:05:13 PM »
I'll rest my above questions and ask some new :)

I've seen that an aluminum plate seems to be the choice for most reflection plates. Is there any other good material that might be equally good to use? I think I read somewhere that a a thin plate of wood was used. How about a plastic one? How thick can a reflection plate be before it starts to interfere with the performance? The thinner the better? All advices for good materials and where I can find it is much appreciated.

Come on Hellfire. You're the master of reflection plates!  ;D

Online Hellfire

Re: Reflection plate design discussion
« Reply #4 on: August 19, 2009, 02:29:55 PM »
I'll rest my above questions and ask some new :)

I've seen that an aluminum plate seems to be the choice for most reflection plates. Is there any other good material that might be equally good to use? I think I read somewhere that a a thin plate of wood was used. How about a plastic one? How thick can a reflection plate be before it starts to interfere with the performance? The thinner the better? All advices for good materials and where I can find it is much appreciated.

Come on Hellfire. You're the master of reflection plates!  ;D
I'll chime in even though I wasn't asked. ;D.

Using steel sheet metal will work just fine. You will have to use the sandwich method. I have so used hardboard (same stuff used for peg board, but without the holes) and 1/8" Plexiglas. One of my most interesting ones was using a mylar disk. Yep, you read that right, mylar disk. 8) Here it is, copied from Vdrums, where I originally posted it.

Quote from: Stoovey;287367
A different way?  You mean you got the laser to work? ;)

I wish I got the laser to work, but no it is not the laser.  I don't want people to get too excited about my triggering, because it is more of a "I could've had a V-8" type idea.  It was a very simple idea that I had about 11-12 years ago and never did anything with it.  What got me thinking about it was a post I saw from one of the other members here.  Here is his post:

Quote from: bogiesbad;283571
The rigid crossbar gives excellent and predictable results and is quite simple IMO. Can't understand why so many want to revamp this design...I have yet to see any evidence of a better one. Watch any of Jman's demo tapes...all the drums perform as good or better than Roland's.

The Poron foam in three layers-two 1/2" and one 3/8" gives a better reproduction of Rollie's cones as anything else I've seen on these boards...now that I think of it, I have seen no demos of any other designs.

I really don't know why so many want to mess with a proven design...but my drums are done (for now) and have performed flawlessly for about three years so I'm content to watching the new guys blaze the new trails...sadly many don't know where they want end up.

 Stimulating a piezo is no big feat...:rolleyes:

So I say thanks bogiesbad for reminding us it is not difficult to stimulate a piezo. I think in a way Roland tried to revamp a proven design as well and made it happen. However, my idea goes back even further than the Roland cross bar/cone foam thing. I guess is was 1996 BC (Before Cones).

Most people when they get into DIY edrumming for the first time, they tend to use the Remo practice pad conversion.  Split the foam in half, attach a piezo to a metal plate of some kind, and sandwich it between the foam halves.  That works OK, (rolls and flams suffer a bit) but for my way to work I need a little more shell depth.  Well, my X4L has that depth.  The system has four layers.

Layers #1 & #2 - 1" thick Poly-fil batting
Layer #3 - mylar disk (yes the same as a drum head) with one 27-mm piezo attached to the bottom with 3M chemical resistant double stick tape.
Layer #4 -  1" thick Poly-fil batting
This is placed under a mesh head.

I know what you are thinking, you're thinking "The piezo wouldn't last 1 hour", but you would be surprised at just how well it works.  I've even road tested already.  (yes, I gig out).  This system is much more sensitive than the old foam-metal-foam style, and it seems it trigger just as good as my Roland cone drums. I most also say that it doesn't feel like you are hitting a foamed back drum trigger.  I think most of us here know that hitting a edrum that has foam behind the head just "feels" bad.  It looses the bounce and has a bad thud. My new sensing system does not feel like you are hitting foam, because you aren't.  Poly-fil is a lot less dense than foam, this is why I use a mylar disk instead of metal. The Poly-fil also, does not dampen the bounce as severally as foam.  The end result of using a mesh head with my new system really does give you the feeling you are playing on an acoustic drum. You still have bounce, but it is not like a trampoline, it is more like a mylar head.

In the pictures you will notice that I had to retro-fit my X4L.  I couldn't have anything in the cake pan because of how close the mylar sensing plate sits to the bottom of the pan, so I ran the wire out the bottom into a project box.  Here's some pictures:









Well, there it is.  I hope people try there own experiments with this system so I am not the only one who knows how good it is.  eDrumming for me is one big experiment, so I am always changing, tweeking, and messing with my designs.

Offline rockdude

Re: Reflection plate design discussion
« Reply #5 on: August 19, 2009, 04:08:23 PM »
That is an impressive build Hellfire!  :) To even think about it is worth some admiration. I thought mylar wasn't stiff enough. I have some left from my kick drum. Maybe I should try it. How was the plexiglas? Do you experience any hot spots with the reflection plate design?

I have found some sheets of aluminum, but they're not big enough to cover the entire area and it might not work properly if I try to fit two sheets together performing as one. But what do I know, I haven't done a real reflection plate yet.

The aluminum sheets are available in the below sizes:
400 x 250 x 0,5
400 x 250 x 1,0
400 x 250 x 1,5
400 x 250 x 2,0

What thickness do you think would work best as a reflection plate?

I'm really starting to like the reflection plate design and the idea behind it, even though i haven't made any yet..I wonder if that's a good sign :o

One more question....Are all the layers just lying on top of each other without any glue holding them together or anything else?..Just the pressure from the drum head.

*Update!*

This night I tried your(Hellfire) reflection plate design with a mylar head as reflection plate on my snare. I was amazed of how my hot spots disappeared! It feels very natural to play on. I really love it!

The downer is that I can't get any good rolls with it yet. Do you think rolls would come through better with an aluminum plate instead? Since it's stiffer I guess it might transfer lighter nuances easier? Or could it be the foam I'm using? It's a quality foam though commonly used when stuffing furnitures. It has a quality of 23kg/m3 and it's 3cm thick. I sandwich the mylar reflection plate between to layers of that foam.

When or if I manage to get good rolls with my setup I will start building a three zone reflection plate design and experiment with eTriggers positional sensing feature with it. I have never tried positional sensing with a reflection plate design so I'm very curious to see if it can output a consistent and solid cc-output. If it could it would be an optimal setup for Alesis Trigger IO since it would be a setup without hotspots and with positional sensing (and that's basically impossible with roland type cones with Alesis Trigger IO). A rare setup in the DIY world I must say. Then again, I have a mountain of trial and error to climb first, but that's the charm of DIY.  8)


 
« Last Edit: August 21, 2009, 07:32:50 AM by rockdude »

Online Hellfire

Re: Reflection plate design discussion
« Reply #6 on: August 21, 2009, 10:01:19 AM »
One more question....Are all the layers just lying on top of each other without any glue holding them together or anything else?..Just the pressure from the drum head.
Correct.

*Update!*

This night I tried your(Hellfire) reflection plate design with a mylar head as reflection plate on my snare. I was amazed of how my hot spots disappeared! It feels very natural to play on. I really love it!

The downer is that I can't get any good rolls with it yet. Do you think rolls would come through better with an aluminum plate instead? Since it's stiffer I guess it might transfer lighter nuances easier? Or could it be the foam I'm using? It's a quality foam though commonly used when stuffing furnitures. It has a quality of 23kg/m3 and it's 3cm thick. I sandwich the mylar reflection plate between to layers of that foam.

When or if I manage to get good rolls with my setup I will start building a three zone reflection plate design and experiment with eTriggers positional sensing feature with it. I have never tried positional sensing with a reflection plate design so I'm very curious to see if it can output a consistent and solid cc-output. If it could it would be an optimal setup for Alesis Trigger IO since it would be a setup without hotspots and with positional sensing (and that's basically impossible with roland type cones with Alesis Trigger IO). A rare setup in the DIY world I must say. Then again, I have a mountain of trial and error to climb first, but that's the charm of DIY.  8)
Keep in mind, I didn't use foam in the above example. I use poly-fil. Much different stuff. If you are using foam, try making your plate from sheet metal. You will find it will work better with your set-up. Let us know what happens. :)

Offline rockdude

Re: Reflection plate design discussion
« Reply #7 on: August 21, 2009, 10:24:26 AM »
Quote
Keep in mind, I didn't use foam in the above example. I use poly-fil. Much different stuff. If you are using foam, try making your plate from sheet metal. You will find it will work better with your set-up. Let us know what happens. :)

I sure will keep you guys update on my progress..if any  ::)

What thickness is preferable for the sheet metal? I posted the thickness of the sheets I can get my hands on earlier in this thread. Have a look and tell me what you think would be most suiting aluminum sheet thickness for the foam I am using. Again thanks for all information!

Online Hellfire

Re: Reflection plate design discussion
« Reply #8 on: August 21, 2009, 10:48:59 AM »
Quote
Keep in mind, I didn't use foam in the above example. I use poly-fil. Much different stuff. If you are using foam, try making your plate from sheet metal. You will find it will work better with your set-up. Let us know what happens. :)

I sure will keep you guys update on my progress..if any  ::)

What thickness is preferable for the sheet metal? I posted the thickness of the sheets I can get my hands on earlier in this thread. Have a look and tell me what you think would be most suiting aluminum sheet thickness for the foam I am using. Again thanks for all information!
Well, it doesn't have to be aluminum. It can be steel as well. I have used roof flashing before. Basically, if you can cut it with tin snips (metal sheers) you can use it. One more thing, how much foam is on top of you plate? If you are having problems with rolls, you might want to use a smaller thickness on top of the plate. It is a balancing act. Too little foam and you hit the plate, Too much foam and you loose nuance. It is going to be trial and error to get the right combo. Good luck.

Offline rockdude

Re: Reflection plate design discussion
« Reply #9 on: August 21, 2009, 12:03:15 PM »
Quote
Well, it doesn't have to be aluminum. It can be steel as well. I have used roof flashing before. Basically, if you can cut it with tin snips (metal sheers) you can use it. One more thing, how much foam is on top of you plate? If you are having problems with rolls, you might want to use a smaller thickness on top of the plate. It is a balancing act. Too little foam and you hit the plate, Too much foam and you loose nuance. It is going to be trial and error to get the right combo. Good luck.

Those I've mentioned earlier in this thread is aluminum sheets and it's one of those that I'll order. It's pretty cheap actually:
 
Aluminum Sheets
 400 x 250 x 0,5 mm     6,59 $    
 400 x 250 x 1,0 mm    8,75 $        
 400 x 250 x 1,5 mm    11,44 $         
 400 x 250 x 2,0 mm    13,32 $

But I'm still wondering what thickness of the above ones will suit my build the best?

The foam I'm using is 3 cm (~1,2 inches) thick. So I have 3 cm foam below the reflection plate and 3 cm foam above it.

Regarding the rolls.....Yes you're probably right. It's a combination of factors that deals with the sensitivity and performance of rolls:

  • Thickness, type and quality of foam.
  • Thickness, type and quality of reflection plate.
  • Mesh head quality and tension.
  • Piezo size and signal output.
  • Module settings.

(I just wished you had the magic answer  ;D)
« Last Edit: August 21, 2009, 12:13:06 PM by rockdude »

Online Hellfire

Re: Reflection plate design discussion
« Reply #10 on: August 21, 2009, 01:24:34 PM »
Those I've mentioned earlier in this thread is aluminum sheets and it's one of those that I'll order. It's pretty cheap actually:
 
Aluminum Sheets
 400 x 250 x 0,5 mm     6,59 $    
 400 x 250 x 1,0 mm    8,75 $        
 400 x 250 x 1,5 mm    11,44 $         
 400 x 250 x 2,0 mm    13,32 $

But I'm still wondering what thickness of the above ones will suit my build the best?
I would stick with .5mm - 1.5mm. Of course if you are trying reproduce the yamaha RHP, I believe they used 3mm. However, the RHP was not a sandwich type reflection plate set-up. The RHP didn't have the foam bottom under the plate. Just foam stand-off blocks. Because of that the RHP needed self supported plates (which actually resonate more because of no foam under the plate). You should not need as thick of a plate using the sandwich method.

Offline rockdude

Re: Reflection plate design discussion
« Reply #11 on: August 21, 2009, 02:15:40 PM »
Quote
I would stick with .5mm - 1.5mm. Of course if you are trying reproduce the yamaha RHP, I believe they used 3mm. However, the RHP was not a sandwich type reflection plate set-up. The RHP didn't have the foam bottom under the plate. Just foam stand-off blocks. Because of that the RHP needed self supported plates (which actually resonate more because of no foam under the plate). You should not need as thick of a plate using the sandwich method.

Then I'll take the middle way and buy the 1.0 mm aluminum sheet. Should be pretty easy to cut in to shape too. If this will work I'm in heaven. I'll certainly convert all of my drums to the reflection plate design if this works. I forgot to mention that my first reflection plate designattempt not only removed all my hot spots, it also allowed me to lower my retrigger settings considerably.

(Just thought of trying an old LP record disc as a reflection plate while I wait for my aluminum sheets to arrive. It's vinyl material so it might work pretty good)
« Last Edit: August 22, 2009, 02:57:54 AM by rockdude »

Offline rockdude

Re: Reflection plate design discussion
« Reply #12 on: August 22, 2009, 04:00:12 AM »
*Update*
Today I cut a piece of hardboard (approximately 3-4mm thick) and put it on top of the mylar reflection plate. And the result.....Instant success! The rolls are ironically better than with my crossbar roland cone type of setup. If this somehow gets even better with the aluminum sheets I'll probably run face first right in to a wall of concrete just for the joy of it.

The only minor thing I can complain about now is that the trigger response closer to the edges isn't as good as in the center of the drum head. I have to whack the drum head harder on the edges than in the center. Maybe the aluminum sheet will fix this since it's thinner and more flexible. I've found some other types of foam to experiment with also. Both are 1cm thick and one of them are softer than my current foam and the other are a bit stronger. Since they are so thin I can put them in layers on top of each other and try different combinations.
« Last Edit: August 22, 2009, 04:05:48 AM by rockdude »

Offline rockdude

Re: Reflection plate design discussion
« Reply #13 on: August 25, 2009, 06:53:03 AM »
Today I found the poly-fil material you used Hellfire! I found it in a local sewing store and also a 20mm thick foam that feels a bit softer than the one in my current build. I think my aluminum sheets will arrive this week and then the reconstruction begins! I have a pretty neat design figured out that I'll try  8) I'll post a list of all the material I used and how I put everything together here later when my build is done.
« Last Edit: August 25, 2009, 06:56:35 AM by rockdude »

Online Hellfire

Re: Reflection plate design discussion
« Reply #14 on: August 25, 2009, 05:18:14 PM »
Today I found the poly-fil material you used Hellfire! I found it in a local sewing store and also a 20mm thick foam that feels a bit softer than the one in my current build. I think my aluminum sheets will arrive this week and then the reconstruction begins! I have a pretty neat design figured out that I'll try  8) I'll post a list of all the material I used and how I put everything together here later when my build is done.
Keep in mind when using poly-fil, that it needs to be packed in. Stuffed just like a stuffed animal. This picture is of my build before I put the head on:

Notice how high the ploy-fil sits before the head is installed.

Offline rockdude

Re: Reflection plate design discussion
« Reply #15 on: August 26, 2009, 02:12:00 AM »
Quote
Keep in mind when using poly-fil, that it needs to be packed in. Stuffed just like a stuffed animal.

Thanks for the advice. I'll use a combination of foam and poly-fil.

Offline rockdude

Re: Reflection plate design discussion
« Reply #16 on: August 28, 2009, 03:29:00 AM »
Quote
Reflection plates always involve the ceramic (of the piezo) facing away from the head (and are also glued onto the surface rather than adhered with foam tape).

Does it really matter if I glue or tape the piezo to the reflection plate in terms of performance? I used a thin doublesided tape when I adhered the piezo to the mylarhead reflection plate, just like Hellfire did and it worked good. Is it any different when using a metal reflection plate or a thicker material than for example mylar?

Online Hellfire

Re: Reflection plate design discussion
« Reply #17 on: August 28, 2009, 09:09:01 AM »
Quote
Reflection plates always involve the ceramic (of the piezo) facing away from the head (and are also glued onto the surface rather than adhered with foam tape).

Does it really matter if I glue or tape the piezo to the reflection plate in terms of performance? I used a thin doublesided tape when I adhered the piezo to the mylarhead reflection plate, just like Hellfire did and it worked good. Is it any different when using a metal reflection plate or a thicker material than for example mylar?
Using tape is fine as long as it is not foam tape. I too use a film double sided tape. I works better than glue. ;)

Re: Reflection plate design discussion
« Reply #18 on: December 27, 2009, 02:48:12 PM »
Hope nobody minds me dragging this up again, but I'm not far off getting my 1mm steel plates back from the metal shop and putting it all together.

Now I've got a roll of 'bed roll' foam like you'd see on a backpacker's pack, does anyone know how this stuff would work compared to the poly-fil foam? I should mention that I have both a regular single ply mylar head and a DIY mesh head made from strong cotton embroidery fabric to experiment with when I get to that stage.

The thoughts I gathered from the previous page were that the combination of foams are more centered around how the head feels for rolls and bounce, rather than the actual performance - is that correct?