Measuring latency of the ZDS Shifter

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EDITORS NOTE
While this article focuses on the ZDS Shifter, everything here applies equally to the Zendrum Stompblock.

Approx. 100us to process message

A typical “pure” MIDI thru device can claim to have zero latency as the MIDI In connection is generally wired directly to the Thru/Out port. However, the Shifter (and the Stompblock) use a soft-thru.

Why a soft thru? It’s because these devices need to receive and analyze the entire MIDI packet (typically 3 bytes) before deciding what to do with it. In the case of the Shifter, this includes looking up and processing any “shift rules” associated with the message before retransmitting the message.

The Shifter is a low-latency device and the average time it takes to process an incoming message is 100 microseconds. That’s a tenth of the milliseconds in which latency is usually expressed and completely imperceptible.


1ms from start of message receipt till start of transmission

However, that’s not the true latency of the device. Because as I pointed out, it needs to wait for the entire message before it can start processing it. This means the REAL latency is about 10 times that, but still only around 1 millisecond and generally below the level that a human can detect.

The conversion to USB adds on a bit more latency that varies in length as it needs to line up with the 32-bit (4-byte) frames that USB uses. On the high end, this can add another 500 to 800 microseconds meaning that the true latency of the Shifter ranges from 1 to 1.8 milliseconds. Your mileage may vary as you also need to take into account the hardware (and software if applicable) on the receiving end.
Generally speaking, if you’re connecting to a hardware sound module or a modern computer you should experience very low latency.

Nearing the finish line!

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I know it’s been quiet around here, but rest assured that the ZDS Shifter has been steadily moving towards a production-ready model!

We were initially projecting it to be available before the end of 2017 and while it certainly will be in final beta by then, I now expect to be accepting orders in early 2018.

A lot of spit and polish has gone into the interface and programming to make sure the final product is as perfect as can be!

As you can probably imagine, with a tool as flexible as the Shifter, there are a great number of setup permutations and scenarios to test — to the point where I’ve had to build out additional hardware testing rigs in order to automate it all. This has taken additional time, but it’s the only way to get it “right”. I won’t put my stamp of approval on each box until I know it can stand up to the abuse of the road and can perform 100% reliably on stage.

Almost here…

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We’re still waiting for the final graphics to arrive, but otherwise, this is exactly what the finished Shifter will be.

In other news, the firmware is receiving its final tweaks and the software should be ready soon. There was a last-minute decision to move the interface into ZenEdit rather than require a separate install. Once all that’s done then it’ll be launch time!

Shape of things to come

Posted 6 CommentsPosted in ZDS Shifter

After going through a number of candidates, I’ve settled on using this aluminum case to house the Shifter; seen here with a Zendrum Merge Brick for size comparison:
20161221_134139
The case is roughly the same width, slightly squatter and a bit wider than the Merge Brick. This feels like the right sweet spot when taking into account cost, internal volume, ruggedness and the need to accommodate two footswitches as low to the ground as possible.

It’s of course possible that the design will change before completion, but I feel confident stating that the final product will look something like this.

More updates soon.