Lights Flickering With Beam

Hi there!

I am using the Beam demo and I love it so far. The only thing is the lights are randomly flickering. The Pars are flickering and the Astera Titan tubes are randomly flashing white. I have tried these lights using other light software (Lightkey) and the lights do not flicker. This is only in Beam. Any idea what might be happening? Thanks!


Hi Spencer,

Thanks for getting in touch! The Astera Titan has 143 different DMX profiles / modes. At the moment only modes 12 and 30 are included in the Beam’s Factory collection. Could it be that your fixture is set to a different mode than one of these two? What you are describing sounds like a mismatch between the used fixture profile and the data the fixture is set to receive.

If you would like to use another mode and need a fixture profile for it, please let me know. For now, here are two additional profiles for modes 15 and 50:

Besides that, it is always helpful to see a screenshot of the Beam’s Monitor while the flickering is happening.

Wanted to bump this because I’m having this same issue. Using 2 cheap RGB PARs from Amazon. They work fine in Lightkey with no flickering at all, but in Beam they flicker (rapidly dim 100-0 and back) consistently, about once every 5-10 seconds.

I’m pretty confident my fixture channel mappings and such are correct. I’ve tried dropping the refresh rate and such to no avail.

No changes are recorded in Beam’s Monitor when the flickering occurs.

I thought I’d attach the manual page related to DMX channel mappings - I would be eternally grateful for an .sbf file for this fixture, if possible. It’s hard to know what a “correct” mapping looks like without a super close comparison in the examples.

Hi @jkymarsh, thanks for reporting the issue. Here is the fixture profile based on your image. To better understand the situation, I would like to ask you for the following info:

  • The exact brand and model of your fixture
  • The computer you are running Beam on (mainly if it is an Intel or M1 Mac) and the macOS version
  • Your Beam Patch file, the Beam Fixture Profile file you made and the accompanying Ableton set (the simplest, most scraped down version of the set that still produces the issue)
  • A screenshot of Beam Monitor
  • How does the flicker look like? Does it look like a single pulse, fast strobing or noisy flickering? Are both fixtures “flickering” exactly in the same manner, at the same time? Could you post a video?
  • What DMX interface are you using to control it?
  • How are you connecting your DMX interface to your computer? If it is a USB DMX interface, is it plugged directly into the USB port, or are you using a USB hub? If it’s a USB hub, are there any other devices plugged into it? If yes, is it an audio interface that is also active while using Ableton? If it is a laptop, is the computer running on battery or power adapter?

The most likely explanation for the behavior you are experiencing is that Beam is for some reason sending DMX values “other than what you would like” to the Strobe (ch5) or Effect (ch6) channels. That can be due to (I am mentioning some things that are maybe already obvious to you, but still mentioning them for others that might come across this post in the future):

  • A wrong fixture profile - here I mostly have in mind wrong channel order or using a fixture profile for the correct fixture, but for a different DMX mode than what the fixture is set to
  • A fixture profile where the default DMX values for Strobe and Effect channels are other than 0 (according to your fixture’s manual these channels need to be set to 0 in order to be used in a continuous, non-strobing manner)
  • DMX starting address mismatch: the starting address in the Beam patch is something else than what is set on the fixture or wrong address offset between multiple fixtures (if the fixture profile channel count doesn’t match the selected DMX mode)
  • Using the Strobe device (in Live) with Strobe Rate set to something other than 0.

While we have not heard whether @schendricks managed to make his Astera Titan Tubes work as expected, I would like to add I was recently able to control 26 Astera Titans using Beam with zero issues in an installation that ran non-stop for ~12-17 hours at a time :-).
Still, there are many reasons why flickering could be happening, including things we are not yet aware of or problems that only appear using certain configurations, so it’s always precious to get these reports and try to get to the bottom of issues together.

Hey Luka, thanks for the fixture file. After using it, I’m still getting the same flickering. Here are a bunch of answers to your questions:

  1. This amazon item:
  2. M1 Macbook Air, Monterey 12.6
  3. Files attached (and I was using your fixture file)
  4. Attached but unhelpful, since Monitor does not reflect the flickering
  5. It’s a single pulse. Video attached
  6. Enttec Open DMX USB
  7. Official Apple USB hub (USB-C to USB-A/HDMI/USB-C). No audio interface is plugged in. Power adapter attached. Also happens on battery.

All the files can be found in this ZIP archive on Drive:

I’m unable to attach all the necessary files directly to this post.

I’m guessing it’s probably just due to these PARs being cheap Amazon garbage, but the fact that they work flawlessly in Lightkey regardless is discouraging.

Update: I have now tried another PAR entirely (Betopper LPC007) using a modified version of the existing Betopper LPC004 profile. I have also tried ditching the Apple USB hub entirely and just using a USB-C-to-USB-A adapter. Flickering is still occurring in exactly the same manner.

I have now also tried running Live both in Rosetta mode and normally. Same conclusion.

At this point there are really no other major variables to change out other than the USB-DMX interface itself, the Enttec Open DMX USB, and buying a considerably more expensive interface is certainly an unappealing notion.

Hey @jkymarsh, thank you for documenting your situation so detailedly! This is very helpful and it indeed points towards a communication issue with the Open DMX interface. One of these boxes is already on my way and I will get back to you as soon as I can do some tests with it myself.

Thanks Luka - I’ve ordered a DMX USB Pro as well, so I’ll be testing that as soon as it arrives.

After a few hours of testing with the DMX USB Pro, the issue seems to be resolved. Appears the Open DMX USB is the problem. It’s a shame that interface is so incredibly flaky, both with Beam and other lighting software. If you’re a user who had similar issues and stumbled across this thread, I’d recommend just investing in the DMX USB Pro and saving yourself the headache.

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Hello back,

Good to know things are running smooth for you with the Enttec DMX USB Pro!
In the meanwhile we were also able to investigate the issue with the Open DMX interface and were able to reproduce the flickering you encountered.

Open DMX is an unbuffered interface, which means it relies on the computer’s CPU to generate the DMX signal. This makes it much more prone to issues than other, buffered interfaces that handle outputting DMX signal themselves (such as DMX USB Pro or any Art-Net node).

After using a logic analyzer to monitor the DMX signal generated by the Open DMX at 40 Hz using Beam, Lightkey and QLC+ with recent Mac computers, it was apparent there are timing issues with this interface using all three softwares. The interface often fails to execute all the instructions (for changing the HI/LO state of the signal) within the available time and the time it takes to execute them varies quite a bit from cycle to cycle. As a result, the fixtures sometimes receive incomplete DMX data, which manifests as flickering.
When using an output rate of 30 Hz (which is the default Open DMX output rate in Lightkey and QLC+), the jittery timing is still there, but the instructions are mostly executed in time, so flickering appears much less often, but still sometimes does, with all three softwares.

It is important to mention that Open DMX output rate is something else than the Beam refresh rate. The latter specifies how often Beam generates DMX data, which is then transmitted as DMX signal at whatever output rate the interface is set to - with buffered USB interfaces and Art-Net nodes this is something you set via the configuration system of the device itself, with Open DMX this is fixed at 40 Hz in the current release version of Beam (1.4).
Since 30 Hz makes this interface a bit more useable, we will in the next version set this as a new default, along with a possibility to change this value by the user.

Still, the timing issues with Open DMX remain and this is unfortunately out of our hands and up to the hardware and the way operating system interfaces it - it seems like this has gotten worse with the recent Mac systems.

Therefore, for anyone that is looking for a reliable lighting control solution, we highly recommend avoiding Open DMX and rather investing in a buffered interface such as DMX USB Pro, or even better, an Art-Net node.

Last but not least, thank you @jkymarsh for shedding light to this problem!

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Thanks a bunch, Luka! Very insightful post and useful information for all of us!

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Update: Beam 1.5 is now out, with the default FTDI output rate lowered from 40 Hz to 30 Hz (which to some extent reduces flickering with Open DMX interfaces). The FTDI output rate can also be set to a custom value in the Preferences. Thanks again to everyone who reported this issue in the past months.