Insert cable for dual BT-1

[ohm-ish]

Hi

I'm having trouble using two Roland BT-1 on one dual input on the eDRUMin (small version).
I use a standard stereo to 2 x mono insert jack cable, (the cable works fine with my kick and snare).
They are set as dual triggers in the interface.

Only one BT-1 pad is triggering.
If I switch the plugs around, then the other pad is working.
Both pads work simultaneously only if I plug the second BT-1 into a separate input on the edrumin.

Hmm what am I missing?

[Dadwrshpdrum]

Monospace on this forum posted this on a different thread.

Roland BT-1: by default in "switch" mode (i.e. with internal crosstalk cancellation enabled; reduced dynamic range)
When used in dual mono mode, *and* reversing polarity or using a splitter cable, Tip will enable "sensor" mode.

Also this is what the unofficial supported pad thread says:

Roland BT-1: Set the input type to 'Mono' for 'sensor' mode, or set the input to 'stereo' and pad type to 'rubber pad' and only use the 'SS' note if you want to use the 'low sensitivity' mode.

On the vdrums forum TangTheHump wrote this

BT-1 Review
The BT-1 is a small, single zone, curved bar trigger pad from Roland. It fits on acoustic drums and electronic drum pads by attaching at a lug point. Or, it can fit over traditional 9 mm, 10 mm, and 12 mm rods used for mounting toms and other percussion equipment. An extra bonus is the BT-1's tube clamping mechanism is flexible enough that it can also clamp over the thread of a cymbal stand. This allows the BT-1 to stack on top of a cymbal. Now you can see why the BT-1 caught my interest!

There is a lot of confusion on the Internet about how the BT-1 is connected and what its sensitivity is. After installing two BT-1s, I can see why. The manual says nothing about the fact the BT-1 can run in default "switch" mode or in "sensor" mode. That's the crux of the problem, so let's discuss this.

The BT-1 is designed to operate in areas where cross talk is a huge problem, such as when attached to the side of a snare drum. Hitting the snare drum may accidentally trigger the BT-1. Roland solved this problem by adding switch circuitry on top of the BT-1's single zone piezo sensor. Hitting the BT-1 closes the switch and only then is input from the piezo sensor processed. This piezo/switch configuration eliminates any possibility of accidental triggering from the snare drum. That's great, however, it comes with two tradeoffs. First, despite being a single zone trigger, for the combined piezo/switch configuration to work, the BT-1 uses both sides of a stereo input. Second, by design, one must hit the BT-1 quite hard to close the switch and this significantly limits sensitivity. Turning up sensitivity on the module has no effect because the heavy-duty switch filters out lighter strokes.

That's the default operating mode of the BT-1 and consequently I read a number of negative reviews stating the BT-1 has limited sensitivity and requires a full stereo input. This is where Roland's manual omissions cheated the product. I'm not sure if this is the case with all modules, but on the TD-30 there are two trigger selections for the BT-1: "BT-1" (switch mode) and "BT-1 sens" (sensor mode). With "BT-1" selected, the BT-1 operates as described above. However, with "BT-1 sens" selected, the switch side of the BT-1 is ignored. This provides two benefits: the BT-1 becomes super sensitive - even light taps with the very tip of a stick are detected, and it is now possible to split two BT-1s across a single, stereo input.

So with all that out of the way, what do I think of the BT-1 and did it solve my ride cymbal problems? Short answer: I love these things and (now) can't imagine being without them. And yes, they work wonderfully as cymbal bell replacements! The feel of the playing surface is lovely. The surface is a thick, soft, spongy rubber that provides lots of rebound, which is great for playing fast bell patterns. Equally important, the surface is quiet when struck... much quieter than a Roland mesh pad or rubber cymbal. When in sensor mode and with the BT-1's stacked on top of cymbal stands, I had no problems with cross talk. And, as mentioned, I was able to achieve superb sensitivity, equal to or better than a mesh pad.

I did have to enhance the sensitivity of the inputs, raising the default of "8" to around "22". There is a roll-off in sensitivity as one moves from the center of the BT-1's bar to the outer edge. Given I'm playing mostly at the edges, that's why the gain increase is necessary. That said, I'm getting a full range of MIDI velocity values, from 0 to 127. Contrast this with the BT-1 in switch mode; when striking with enough force to close the switch, the BT-1 outputs a MIDI velocity value of around 60 to 70. That's the minimum velocity output and the resulting range is from 70 to 127. I can see why those using the BT-1 in switch mode are complaining about limited sensitivity. However, that's not really the problem here. As noted previously, switch mode is intended for extreme environments where cross talk is a substantial problem. The tradeoff for eliminating cross talk is limited dynamics. The real problem is Roland didn't document the different modes of the BT-1 and how and where to use them!

Let's zoom in on using the BT-1 as a bell trigger. Attaching it to the thread of a cymbal stand is easy because all required parts are included. Each BT-1 includes a cable, but I found these cables much too short to reach my module. Thus, I had to sub in my own cables. I've not yet brewed a solution for stopping BT-1 cables touching the cymbals. However, while playing, I didn't notice any impact from the cables resting lightly on the cymbals - the cymbals still swing easily and naturally, there is no loss in sensitivity, and there is no false triggering.

Normally, when playing bow-to-bell patterns, one approaches from 90 degrees off axis such that the tip of the stick contacts the bow and the shank contacts the bell. This isn't quite possible with the BT-1 because the unit doesn't reach far enough around the circumference of the cymbal. Also, one must reach slightly higher than where the bell normally is. In totality, I found a slight playing adjustment in bow-to-bell approach is required, but the result is well worth it. There's a confidence in having the BT-1 there (it always triggers reliably and with the lightest of touches) as opposed to the default bell on Roland ride cymbals which never triggers reliably. The sensitivity, feel, and overall performance of the BT-1 actually outshine the overall triggering performance of the entire cymbal!

In terms of construction, the outer housing of the BT-1 is plastic, but the inner core is a thick, heavy metal. The clamping components are all metal and attach to the inner metal core so the unit feels completely solid when attached. Weight-wise, while I wouldn't say the BT-1 is overly heavy, non-the-less, it's not light either. It feels like a solid, well-built unit. The finishing of the bar and all components is top notch.

Some reviews noted the price as a negative. The BT-1 sells for around $100. When considering the careful design that has gone into this unit and its overall quality, I think the price is very reasonable. I mean, let's face it... Roland isn't going to sell bucket loads of these things so they have to make up the design costs somehow. This is one of the rare occasions I think a V-Drums product is priced spot on.

Would I buy the BT-1 again? Absolutely! Will I buy more? Probably! The BT-1 is such a useful, compact, great feeling trigger unit that I can't imagine any e-drummer not finding a use for them. It's great for ride bells, a second pair of close hats (an x-hat), and all kinds of percussion. In sensor mode, the feel, triggering, and sensitivity are equal to a mesh pad so you could easily use these to add extra drums in tight spaces, such as a secondary snare voice beside the main snare.

Pros:
- Switch mode guarantees no cross talk in high cross talk environments.
- Sensor mode provides sensitivity equivalent to a mesh pad with full range of MIDI velocity, from 0 to 127.
- No problems with cross talk when stacked on a cymbal stand and in sensor mode.
- Can use a split stereo input to handle two BT-1s when the BT-1s are in sensor mode.
- Feels great, with nice sponginess and lots of rebound (feels much better than a typical rubber pad).
- Sturdy, reliable construction with internal metal frame.
- Attaches easily to lug points, rods (9 mm, 10 mm, 12 mm), and cymbal stands.

Cons:
- Switch mode limits sensitivity to hard hits and provides only upper MIDI velocities, starting at 60 to 70 and up.
- Included cable too short for many applications.
- Instructions don't discuss BT-1 modes or how to enable them.
- Custom wiring needed to obtain sensor mode with certain modules.


Review Afterthoughts
I read the BT-1 manual again (cover to cover) to confirm there is no mention of sensor mode. That is indeed the case. What became clearer this time is I suspect a customer's just-out-of-the-box experience with the BT-1 is highly dependent on the module they're using. In my case, the TD-30 supports both switch and sensor modes, but the default mode is switch (due to how the BT-1 is wired) and I suspect, given what I read in the manual, that this is the only option available on certain modules. In switch mode, the BT-1 absolutely would not work for my application.

If the module you're using doesn't support sensor mode (some of Roland's modules don't even have a trigger setting for the BT-1), one can probably obtain sensor mode by wiring a custom cable. At that point, all the praise I've heaped on the BT-1 still applies, but the initial out-of-box experience is lackluster in these situations, especially given the manual makes no mention of how to obtain and/or wire for sensor mode.

Given it's a reasonably simple wiring problem to move between switch and sensor modes (defeat the cross talk switch and have the piezo show up on the desired side of the stereo pair), I don't understand why Roland didn't provide just such a toggle switch on the BT-1. Perhaps production cost was an issue? Or, maybe Roland's engineers didn't realize customers would want to use the BT-1 with the cross talk filtering disabled? At any rate, this would certainly be a great improvement for the BT-1 version 2.

Regarding my comment "no problems with cross talk when stacked on a cymbal stand and in sensor mode", this is true, but more explanation is needed. I fitted the threads of my cymbal stands with thick, clear, fish tank tubing. This tubing protects the threads from the BT-1's clamp and acts as a vibration insulator. Cross talk may be an issue without this insulation, but there were no issues with the insulation in place.

Important: For the BT-1 trigger types to be present in the TD-30, the TD-30's operating system must be version 1.12 or later. If your unit has a lesser version, you'll need to update the operating system.

[monospace]

Yeah, just using a regular stereo splitter won't cut it with the BT-1. You may have more luck with a Keith Raper Circuit but I haven't tried that.