It’s been a full week of Stem-related news, starting with the launch of Stem Decks + Traktor 2.9 on Monday and our launch of a Midi Fighter Twister mapping yesterday. One of the biggest questions people have asked has been “Why can’t I see the individual Stems in Traktor?” so we decided we would reach out directly to Native Instruments and find out. Learn more about how waveforms, GPUs, and CPUs all play into the state of Stem Deck displays.
STEM DECKS = GPU HARDWARE REQUIRED
Apparently, in order to process the individual Stem Deck files, Native Instruments is drawing independent Stem waveforms for each deck. What that means is that there are now four waveforms being processed on the fly for a single deck – which could end up being 16 waveforms at once if all four decks are in Stem Deck mode.
According to Native Instruments, this becomes a big issue for your computer’s processor – meaning it’s best farmed out to your graphics processor – but Traktor’s interface is all rendered on the CPU. Here’s what they write:
Graphic rendering of the individual Stem tracks is currently only possible on the displays of the TRAKTOR KONTROL S8 / D2 controllers since those graphics are rendered via the computer’s GPU (Graphics Processing Unit). However, unlike the TRAKTOR KONTROL S8 / D2, the TRAKTOR GUI is not rendered on the GPU. Instead, it is rendered on the computer’s CPU. Rendering four waveforms per Stem Deck increases the CPU load drastically and leads to performance issues (audio crackling, distorsions, unresponsive software interface).
Native Instruments is currently testing ways to either reduce the CPU usage of the waveform drawing or utilize the GPU, thus allowing the display and interaction with Stems in the TRAKTOR software.
So even though you can control and MIDI map any DJ controller to individual Stems, you can’t see the heads up display of what’s happening.
WORKAROUND: MIDI VU METERING
What Native Instruments hasn’t taken into account in their response is another temporary workaround to allow MIDI controllers to display some visual feedback from a Stem Deck. It’s possible to MIDI-map the VU meters in Traktor from any Deck (Track Decks, Remix Deck slots, and Stem Deck slots) to your LEDs on your DJ controller.
In the DJTT MIDI mapping for the Twister and Stem Decks, we’ve done exactly that to give some sense of “what’s playing” and it works very well! Learn how to map VU meters yourself in this tutorial: