Isolation GPI RIM?

[Oldblindjim]

In doing research for my first edurm kit, I've found this question to be coming back to me.

Why try to isolate the mounting system for the trigger?

Wouldn't isolating the whole shell be a better way. It seems you would want the impact to pass through to the piezo from the head without the trigger moving away at the same time. That way a more actuate encounter with the head would occur. To prevent the other drums from setting off the trigger, wouldn't products like RIMS be the way to go?

OBJim

[JmanWord]

I have had rim suspension mounts on all my converted acoustic kits and really no crosstalk problem between drums. I use a rack also.

When talking about isolating of the trigger itself it depends on a couple things. What module or TMI you would be using, and whether the drums are single or dual zone.

[Oldblindjim]

I have had rim suspension mounts on all my converted acoustic kits and really no crosstalk problem between drums. I use a rack also.

When talking about isolating of the trigger itself it depends on a couple things. What module or TMI you would be using, and whether the drums are single or dual zone.

I just got my Alesis Trigger i/O. All the toms will be singles and the snare dual.

With the snare I can understand the reasoning to iso the snare from the rim.

[Gastric]

If you're going for a single trigger drum I don't see any reason to expend much (or probably ANY) time, effort, and money into isolation.

Like I said in my DIY thread I followed Beatnik's crossbar design which has bonded rubber washers and rubber expansion nuts for isolation but it certainly doesn't completely isolate the head piezo anyway. You can still whack the rim and shell and trigger the head. Now, whether or not that small amount of isolation lends itself to greater success in dual-trigger drums I can't say yet. But it's a seemingly small amount of isolation.

From the few reviews I've read your Trigger IO should be able to isolate well via module settings anyway. I've yet to see any complaints of unsolvable crosstalk related to the Trigger IO, but the exact opposite. Mine arrives tomorrow so I'll get some first hand experience soon.

[Oldblindjim]

If you're going for a single trigger drum I don't see any reason to expend much (or probably ANY) time, effort, and money into isolation.

Like I said in my DIY thread I followed Beatnik's crossbar design which has bonded rubber washers and rubber expansion nuts for isolation but it certainly doesn't completely isolate the head piezo anyway. You can still whack the rim and shell and trigger the head. Now, whether or not that small amount of isolation lends itself to greater success in dual-trigger drums I can't say yet. But it's a seemingly small amount of isolation.

From the few reviews I've read your Trigger IO should be able to isolate well via module settings anyway. I've yet to see any complaints of unsolvable crosstalk related to the Trigger IO, but the exact opposite. Mine arrives tomorrow so I'll get some first hand experience soon.

Good enough...On with the madness!

OB Jim

[JmanWord]

I think Isolation mounts for toms are a great idea. Like I say they all but eliminate crosstalk problems between drums. With Roland modules, isolating head and rim piezos from each other is not a good idea. The way the dual piezo inputs work requires the head piezo to determine the velocity of rim shots as well as head shots, so Completely isolate the rim piezo from the head piezo and you get NO rim shot.

The Trigger Io works differently: The head zone and the rim zone are treated as 2 independent zones. In that case it can't hurt a bit to try to isolate the 2 zones. As Gastric stated the Io has a pretty sufficient Xtalk cancel setting so it is not imperitive that you get complete isolation between the zones, but, like I say, it couldn't hurt.

[Oldblindjim]

I think Isolation mounts for toms are a great idea. Like I say they all but eliminate crosstalk problems between drums. With Roland modules, isolating head and rim piezos from each other is not a good idea. The way the dual piezo inputs work requires the head piezo to determine the velocity of rim shots as well as head shots, so Completely isolate the rim piezo from the head piezo and you get NO rim shot.

The Trigger Io works differently: The head zone and the rim zone are treated as 2 independent zones. In that case it can't hurt a bit to try to isolate the 2 zones. As Gastric stated the Io has a pretty sufficient Xtalk cancel setting so it is not imperitive that you get complete isolation between the zones, but, like I say, it couldn't hurt.

OK so if I deal with a number of dual zone triggers I'll be in for a lot of tweaking the i/O to try and iso the rim shot. It almost seems that maybe I should use the "Iso Rim" device to use as the triggering surface itself. In a sense like the Yamaha stick board on the cocktail drum. Get it up high enough to strike and still be function and the Iso for the drum.

I'll have to think about this one.

[Gastric]

That is true. If you're mounting your toms to your bass like with a standard non-rack kit you will get quite a bit of crosstalk between the toms and bass. But I'm still not sure what the rubber isolation REALLY provides. Has anyone done actual step-by-step testing or do we just follow this procedure because it's on a webpage? I'm not criticizing, I'm geniunely asking.

I briefly did some testing with my current triggers and crossbars and my Alesis D4 which has a little 16-bar meter to display trigger signal.

* My 12" and 13" rack toms which have the trigger plate isolated with the expansion nuts get 16 bars on the head and 2 bars on the rim, that's both measured via the head piezo and with crosstalk disabled for the testing.
* My 16" floor tom which currently has the piezo isolation plate removed and the piezo directly attached to the crossbar gets 16 bars on the head and between 7 and 16 bars on the rim.
* But then for giggles I removed the head, installed the piezo isolation plate, reinstalled the head, and I appear to have the same performance. I can still get plenty of signal through the head piezo by hitting the rim or shell.
* My 14" metal snare also currently has the piezo isolation plate removed and the peizo directly attached to the crossbar. It gets 16 bars on the head, rim, or shell. And still like 7-8 bars when hitting the snare stand. I did not reinstall the piezo plate to test with.

Certainly not scientific by any means. But on my floor tom which I ran quickly with and without the piezo plate installed (which uses rubber expansion nuts) I saw no difference between head/rim isolation.

Why do my smaller toms seem to have better head/rim isolation? Couldn't tell you. They're mounted to the bass drum so maybe that larger mass eats up some of the rim energy? A better test would apparently be to disassemble the 12/13 toms and remove/install the piezo plate to see if it measurably affects either of them since they're the two drums that seem to have the best head/rim isolation.

Generally speaking for DIY projects I follow the crowd assuming that dozens of people doing this for years have ironed out the bugs and figured out the "best" way to do it. I'm certainly not saying all the rubber washers and expansion nuts HURT anything. And they don't impart a monumental cost to the drum, maybe $3 per drum at most. At this point I'm just not sure they really do anything significant.

[JmanWord]

Most on this forum have been using Roland modules with their DIY. With Roland modules the isolation between trigger zones (with dual piezo pads/inputs) is not really a concern as I mentioned above. You need the zones to interact. So if people in that respect are trying to isolate rim from head.... it should only be in order to even out response.... Some may think their rim zone is hotter than necessary. But, like I say very little isolation if any is needed on Rollie modules.

So, it is a question of adding more isolation points and experimentation for the Io for example. When testing my snares on the Io I got reasonably good response for head and rim with nothing dif than I use for my normal Roland set up. With just a min of Crosstalk adjustment everything worked reasonably well.

Now the ideal thing for the Trigger Io would be to have more isolation between the zones. I always mount my rim piezos to the shell. If I were to want more isolation ... to begin with I would add rubber or vinyl gaskets between crossbar bracket and shell. And possibly more rubber between the center trigger plate and bar, although just well nuts, or rubber spacers should be sufficient. Those kind of things should cut back the amount of crosstalk from the rim when playing the head. When playing the rim there is bound to be a slight amount of reaction with the head as the rim tightens down on the head. But, as already mentioned the Trigger Io doesn't really need complete isolation between the zones ..... a little bit of additional rubber here or there oughta get you a pad that would dial in real well...

And if you think something would isolate more than rubber ... a dense foam maybe.... try a couple different things... In the end though the response is what you are after, and if you get satisfactory results, then don't fix it.